Universe News (miscellaneous articles)

[Draggendrop Veteran]

Just a follow up to jjkusaf's post on the Kepler issue.

 

Just a bit of background for those not too familiar with it....

 

Mission Overview

 

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March 6, 2009

Goal: Survey our region of the Milky Way for Earth-size and smaller planets in or near the habitable zone, determine how many stars in our galaxy might have such planets.

http://www.nasa.gov/mission_pages/kepler/main/index.html

 

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Kepler Science

The scientific objective of the Kepler Mission is to explore the structure and diversity of planetary systems. This is achieved by surveying a large sample of stars to:

Determine the percentage of terrestrial and larger planets that are in or near the habitable zone of a wide variety of stars
Determine the distribution of sizes and shapes of the orbits of these planets
Estimate how many planets there are in multiple-star systems
Determine the variety of orbit sizes and planet reflectivities, sizes, masses and densities of short-period giant planets
Identify additional members of each discovered planetary system using other techniques
Determine the properties of those stars that harbor planetary systems.

The Transit Method of Detecting Extrasolar Planets

When a planet passes in front of a star as viewed from Earth, the event is called a “transit”. On Earth, we can observe an occasional Venus or Mercury transit. These events are seen as a small black dot creeping across the Sun—Venus or Mercury blocks sunlight as the planet moves between the Sun and us. Kepler finds planets by looking for tiny dips in the brightness of a star when a planet crosses in front of it—we say the planet transits the star.

Once detected, the planet's orbital size can be calculated from the period (how long it takes the planet to orbit once around the star) and the mass of the star using Kepler's Third Law of planetary motion. The size of the planet is found from the depth of the transit (how much the brightness of the star drops) and the size of the star. From the orbital size and the temperature of the star, the planet's characteristic temperature can be calculated. From this the question of whether or not the planet is habitable (not necessarily inhabited) can be answered.

An artists rendering of what our galaxy might look as viewed from outside our Galaxy. Our sun is about 25,000 light years from the center of our galaxy.
Credits: NASA Ames

 

When a planet crosses in front of its star as viewed by an observer, the event is called a transit. Transits by terrestrial planets produce a small change in a star's brightness of about 1/10,000 (100 parts per million, ppm), lasting for 2 to 16 hours.
Credits: NASA Ames

 

Kepler's Field Of View In Targeted Star Field
Credits: NASA Ames

 

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Target Field of View

Since transits only last a fraction of a day, all the stars must be monitored continuously, that is, their brightnesses must be measured at least once every few hours. The ability to continuously view the stars being monitored dictates that the field of view (FOV) must never be blocked at any time during the year. Therefore, to avoid the Sun the FOV must be out of the ecliptic plane. The secondary requirement is that the FOV have the largest possible number of stars. This leads to the selection of a region in the Cygnus and Lyra constellations of our Galaxy as shown.

http://www.nasa.gov/mission_pages/kepler/overview/index.html

 

The K2 series are mission extensions for this payload.

 

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Kepler space telescope in emergency mode

 

Artist’s concept of the Kepler observatory. Credit: NASA

 

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Mission controllers are trying to diagnose a problem that put NASA’s Kepler planet-hunting observatory in emergency mode nearly 75 million miles from Earth this week.

 

Circling the sun in an orbit just outside Earth’s, Kepler is in an extended mission searching for worlds around other stars.

 

Engineers discovered the spacecraft was in emergency during a regularly-scheduled communications session Thursday, NASA said in a statement.

The agency said emergency mode is the observatory’s lowest operational mode and is fuel-intensive, meaning the spacecraft is burning its finite supply of hydrazine fuel at a faster rate than usual.

 

Managers declared a spacecraft emergency, giving the Kepler team priority access to NASA’s Deep Space Network, a global array of communications antennas used to contact faraway space probes, officials said in a statement.

 

“Recovering from EM (emergency mode) is the team’s priority at this time,” the statement said.

 

At Kepler’s distance from Earth, it takes 13 minutes for a communications signal to travel to the spacecraft and back, according to NASA.

 

The problem that led to Kepler’s default into emergency mode occurred some time between April 4 — the craft’s last normal communications session — and the contact April 7.

 

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Kepler was about to conduct a flip maneuver to aim its 3.1-foot (95-centimeter) telescope in the direction the spacecraft is traveling in its orbit. The observatory has been pointing in the opposite direction.

 

The change in orientation was supposed to allow Kepler to point toward the center of the Milky Way galaxy to take part in a search for rogue planets, bodies that are careening through the galaxy without orbiting a star. Ground-based observatories also planned to participate in the project.

 

Officials said Friday that the anomaly aboard Kepler apparently occurred before the flip maneuver.

 

Kepler is in an extended science campaign dubbed K2 that began in 2014 after two of the four reaction wheels aboard the observatory failed, rendering the spacecraft unable to maintain the ultra-stable pointing required for its original mission.

 

The wheels spin between 1,000 and 4,000 rpm, generating momentum for precise pointing of the telescope. Two wheels are not enough to keep the telescope staring at the same region of the sky for long durations, and Kepler’s chemical rocket thrusters do not have fine pointing capability.

 

During Kepler’s four-year primary mission — from the observatory’s launch in March 2009 until early 2013 — the craft aimed its telescope at the same field of more than 150,000 stars in the constellations Cygnus and Lyra. Astronomers sought an Earth-sized planet at just the right distance from a sun-like star in hopes of discovering something like an “Earth analog” where life could exist.

 

Kepler’s 95-megapixel camera watches for the slight dimming of starlight caused when an object passes between the star and the telescope.

Scientists adjusted the observation plan for the K2 mission with the loss of two reaction wheels, programming Kepler to shift its gaze to different parts of the sky every few months.

 

Astronomers analyzing data acquired by Kepler discovered more than 1,000 confirmed exoplanets, making the mission the most prolific planet-hunter in history. About 4,000 other exoplanet candidates have been detected by Kepler, but those discoveries are provisional and require follow-up observations to confirm they are not false positives.

 

Officials previously said the failure of another reaction wheel would further degrade its pointing precision, likely spelling the end of Kepler’s science mission.

http://spaceflightnow.com/2016/04/09/kepler-space-telescope-in-emergency-mode/

 

[BetaguyGZT]

DSS-14 (Goldstone) and DSS-43 (Canberra) both have downlink from Kepler; but the data stream is extremely shallow, both in data rate and in strength. Looks like Kepler's kicking the bucket for good this time.  

 

These two are the big dishes; the ones that people normally associate the two sites with ... and they're visible from space. 

 

[EDIT] Uh-oh. They've both stopped receiving in the last two minutes. Either they're swapping gear or they've given up.  

[Draggendrop Veteran]

The communications have been sporadic all day...depends on orbital location reference to earth's DSN sites and the command/reply regime they are attempting. But I agree, I think it's toast, pretty much was done when the reaction wheels went bonkers a while back. For this type of mission, platform stability is everything. In the failure mode we have now, if it persists, there won't be enough fuel left, it's being used for emergency stabilization right now.

[BetaguyGZT]

Yeah.  That's a really #### kind of EM though. Instead of a free drift and an omnidirectional antenna (and whose bright frigging idea was it to place Kepler 70+ million miles away?!) where a failure mode could simply mean "we drift in our orbit until corrected, then the reaction wheels can straighten us out" (saving the RCS propellant), it's using it up in a completely pointless and futile manner simply because it doesn't know any better -- and because there's no OD antenna (not even for backup purposes), they can't tell Kepler to NOT do that.

 

AKA because some jackwagons weren't thinking things through and using some common sense. /sigh

 

It wasn't necessary to have Kepler out that far. For starters. 70+ million miles ... only NASA/JPL mission planning could be that ignorant of common sense.

 

It does no good for me to get on a rant about them now. Suffice it to say they're the dumbest smart people on the planet.

[Jim K Global Moderator]

Kepler Recovered!

 

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Mission Manager Update: Kepler Recovered from Emergency and Stable

 

Mission operations engineers have successfully recovered the Kepler spacecraft from Emergency Mode (EM). On Sunday morning, the spacecraft reached a stable state with the communication antenna pointed toward Earth, enabling telemetry and historical event data to be downloaded to the ground. The spacecraft is operating in its lowest fuel-burn mode.

 

The mission has cancelled the spacecraft emergency, returning the Deep Space Network ground communications to normal scheduling.

 

Once data is on the ground, the team will thoroughly assess all on board systems to ensure the spacecraft is healthy enough to return to science mode and begin the K2 mission's microlensing observing campaign, called Campaign 9. This checkout is anticipated to continue through the week.

 

Earth-based observatories participating in Campaign 9 will continue to make observations as Kepler's health check continues. The K2 observing opportunity for Campaign 9 will end on July 1, when the galactic center is no longer in view from the vantage point of the spacecraft.

 

K2's previous science campaign concluded on March 23. After data was downlinked to the ground, the spacecraft was placed in what is termed Point Rest State (PRS). While in PRS, the spacecraft antenna is pointed toward Earth and it operates in a fuel-efficient mode, with the reaction wheels at rest.

 

The Emergency Mode began approximately 14 hours before the planned maneuver to orient the spacecraft toward the center of the Milky Way for Campaign 9. The team has therefore ruled out the maneuver and the reaction wheels as possible causes of the EM event. An investigation into what caused the event will be pursued in parallel, with a priority on returning the spacecraft to science operations.

 

The anomalous EM event is the first that the Kepler spacecraft has encountered during its seven years in space. Mission operations at NASA's Ames Research Center in California's Silicon Valley, Ball Aerospace and the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder remain vigilant.

 

It was the quick response and determination of the engineers throughout the weekend that led to the recovery. We are deeply appreciative of their efforts, and for the outpouring of support from the mission's fans and followers from around the world.  We also recognize the tremendous support from NASA’s Deep Space Network, managed by the Jet Propulsion Laboratory in Pasadena, California, and to NASA’s other missions that surrendered their scheduled telemetry links in order to provide us with the resources needed to protect the Kepler spacecraft.

 

Updates will be provided as information warrants.

Regards,

Charlie Sobeck
Kepler and K2 mission manager
NASA's Ames Research Center

http://www.nasa.gov/feature/mission-manager-update-kepler-recovered-from-emergency-and-stable

 

 

[DocM]

One big problem with this and several other missions has been the move away from lead solder due to leads toxicity. Replacement solders and coatings often contain varying amounts of tin, and tin has a habit of growing nano to macro scale whiskers on its surface, which can cause short circuits and premature device failures. This has caused a move to partially roll back the anti-lead initiative until a solution can be found.

 

http://nepp.nasa.gov/whisker/background/

 

 

[BetaguyGZT]

Yep, old Sylvania TV's get these tin whiskers that first collect in the potentiometers, which then end up everywhere else; causing shorts and eventual failure.They're a nuisance for Restoration Buffs and everyone else who work on Electronics (Engineers, etc) -- and are pointed to as being the primary points of failure in pretty much every piece of gear that use tin solder.

 

Nasty little blighters; and you'll feel 'em if you get them in your skin. "Death by a thousand cuts" was never a more appropriate term here.

[+JHBrown Subscriber¹]

Just wanted to stop in and say thank you all for posting all of this wonderful information. I am an amateur, but enthusiasts, on anything dealing with astronomy. It has always been an interest of mine since I was a young lad. Keep up the excellent work...

[BetaguyGZT]

In the grand scheme of things we're all enthusiasts regardless of education level. There's always room to get a degree if you like something enough. Brian May of Queen started working on his Doctorate in the mid 90's; and now look at him. He's one of the ESA Scientists working on the New Horizons mission!  

 

He's the real-life Buckeroo Banzai.

[Draggendrop Veteran]

5 hours ago, Unobscured Vision said:

Yep, old Sylvania TV's get these tin whiskers that first collect in the potentiometers, which then end up everywhere else; causing shorts and eventual failure.They're a nuisance for Restoration Buffs and everyone else who work on Electronics (Engineers, etc) -- and are pointed to as being the primary points of failure in pretty much every piece of gear that use tin solder.

 

Nasty little blighters; and you'll feel 'em if you get them in your skin. "Death by a thousand cuts" was never a more appropriate term here.

This is why, for many decades, I use only "eutectic solder" and liquid rosin flux, as well as conformal coatings where applicable. It is expensive, but a better way to mitigate undesirable issues.

 

[Draggendrop Veteran]

Hubble Frames a Unique Red Rectangle

 

HD 44179                      NASA/ESA/STSCI

 

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The star HD 44179 is surrounded by an extraordinary structure known as the Red Rectangle. It acquired its moniker because of its shape and its apparent color when seen in early images from Earth. This strikingly detailed Hubble image reveals how, when seen from space, the nebula, rather than being rectangular, is shaped like an X with additional complex structures of spaced lines of glowing gas, a little like the rungs of a ladder.

 

The star at the center is similar to the sun, but at the end of its lifetime, pumping out gas and other material to make the nebula, and giving it the distinctive shape. It also appears that the star is a close binary that is surrounded by a dense area of dust — both of which may help to explain the very curious shape.

 

The Red Rectangle is an unusual example of what is known as a proto-planetary nebula. These are old stars, on their way to becoming planetary nebulae. Once the expulsion of mass is complete a very hot white dwarf star will remain and its brilliant ultraviolet radiation will cause the surrounding gas to glow. The Red Rectangle is found about 2,300 light-years away in the constellation Monoceros (the Unicorn).

 

The High Resolution Channel of the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys captured this view of HD 44179 and the surrounding Red Rectangle nebula — the sharpest view so far. Red light from glowing Hydrogen was captured through the F658N filter and colored red. Orange-red light over a wider range of wavelengths through a F625W filter was colored blue. The field of view is about 25 by 20 arcseconds.

http://www.nasa.gov/image-feature/goddard/2016/hubble-frames-a-unique-red-rectangle

 

http://spaceref.com/astronomy/hubble-views-the-red-rectangle.html

 

[BetaguyGZT]

WOW. I'm looking at that and trying to piece together the math that would be present in order for that structure to exist.

 

There's gotta be more at play than just a binary companion here. That's some very complex physics at work.

 

Carl Sagan would have loved this image.  

[Jim K Global Moderator]

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1917 Astronomical Plate Has First-Ever Evidence of Exoplanetary System

 

Pasadena, CA— You can never predict what treasure might be hiding in your own basement. We didn’t know it a year ago, but it turns out that a 1917 image on an astronomical glass plate from our Carnegie Observatories’ collection shows the first-ever evidence of a planetary system beyond our own Sun. This unexpected find was recognized in the process of researching an article about planetary systems surrounding white dwarf stars in New Astronomy Reviews.

 

Here’s what happened: about a year ago, the review’s author, Jay Farihi of University College London, contacted our Observatories’ Director, John Mulchaey. He was looking for a plate in the Carnegie archive that contained a spectrum of van Maanen’s star, a white dwarf discovered by Dutch-American astronomer Adriaan van Maanen in the very year our own plate was made.

 

/snip

 

Only within the last 12 years has it become clear to astronomers that van Maanen's star and other white dwarfs with heavy elements in their spectra represent a type of planetary system featuring vast rings of rocky planetary remnants that deposit debris into the stellar atmosphere. These recently discovered systems are called “polluted white dwarfs.” They were a surprise to astronomers, because white dwarfs are stars like our own Sun at the end of their lifetimes, so it was not at all expected that they would have leftover planetary material around them at that stage.

 

“The unexpected realization that this 1917 plate from our archive contains the earliest recorded evidence of a polluted white dwarf system is just incredible,” Mulchaey said. “And the fact that it was made by such a prominent astronomer in our history as Walter Adams enhances the excitement.”

 

/snip

 

Caption: The 1917 photographic plate spectrum of van Maanen's star from the Carnegie Observatories’ archive. The pull-out box shows the strong lines of the element calcium, which are surprisingly easy to see in the century old spectrum.  The spectrum is the thin, (mostly) dark line in the center of the image. The broad dark lanes above and below are from lamps used to calibrate wavelength, and are contrast-enhanced in the box to highlight the two “missing” absorption bands in the star. Available here as a standalone image. Credit: Carnegie Institution for Science.

 

 

Full article at Carnegie Science

[BetaguyGZT]

I wonder how many of those old plates and slides will show something similar, now that they know what to look for. And, since they know what is [in] the spectra now (and what it isn't), who knows what else they could find?

 

Fascinating indeed.  It could prove some of those old Astronomers' who were ridiculed and even laughed at back then (and had their careers ruined) correct -- and give them and their work vindication.

Edited April 12, 2016 by Unobscured Vision

[Draggendrop Veteran]

'Bizarre' Group of Distant Black Holes are Mysteriously Aligned

 

This is an image of the deep radio map covering the ELAIS-N1 region, with aligned galaxy jets. The image on the left has white circles around the aligned galaxies; the image on the right is without the circles.
Credit: Andrew Russ Taylor

 

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A highly sensitive radio telescope has seen something peculiar in the depths of our cosmos: A group of supermassive black holes are mysteriously aligned, as if captured in a synchronized dance.

These black holes, which occupy the centers of galaxies in a region of space called ELAIS-N1, appear to have no relation to one another, separated by millions of light-years. But after studying the radio waves generated by the twin jets blasting from the black holes' poles, astronomers using data from the Giant Metrewave Radio Telescope (GMRT) in India realized that all the jets were pointed in the same direction, like arrows on compasses all pointing "north."

 

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This is the first time a group of supermassive black holes in galactic cores have been seen to share this bizarre relationship and, at first glance, the occurrence should be impossible. What we are witnessing is a cluster of galaxies, that all have central supermassive black holes that have their axes of rotation pointed in the same direction.

"Since these black holes don't know about each other, or have any way of exchanging information or influencing each other directly over such vast scales, this spin alignment must have occurred during the formation of the galaxies in the early universe," said Andrew Russ Taylor, director of the Inter-University Institute for Data Intensive Astronomy in Cape Town, South Africa. Taylor is lead author of the study published in the journal Monthly Notices of the Royal Astronomical Society.

In other words, though each of these galaxies are currently independent from one another, they likely originated from the same small-scale mass fluctuation, shortly after the Big Bang, and therefore used to have some commonality on a quantum scale. These objects were all spawned in the same compact region of primordial space some 13.8 billion years ago that, as the universe expanded, drifted apart into the mature galaxies we see today in that distant volume of space.

 

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Interestingly, the discovery of these aligned black holes came about by accident. In preparation for the completion of the South African MeerKAT radio telescope and Square Kilometre Array (SKA) — which is set to become the most powerful radio telescope on the planet — the researchers used the powerful GMRT to find the faintest radio signals possible so targets could be found for MeerKAT and SKA to further investigate. Both systems will be many times more powerful than the radio observatories we currently have available, so it looks like they already have a vexing puzzle to solve.

http://www.space.com/32549-bizarre-group-of-distant-black-holes-are-mysteriously-aligned.html

[BetaguyGZT]

Yeah, I read about this before. Strange, isn't it?

[Draggendrop Veteran]

Dwarf Galaxy Found Lurking In Another Galaxy's Halo

 

Composite image of the gravitational lens SDP.81 showing the distorted ALMA image of the more distant galaxy (red arcs) and the Hubble optical image of the nearby lensing galaxy (blue center object). By analyzing the distortions in the ring, astronomers have determined that a dark dwarf galaxy (data indicated by white dot near left lower arc segment) is lurking nearly 4 billion light-years away.
CREDIT
Y. Hezaveh, Stanford Univ.; ALMA (NRAO/ESO/NAOJ); NASA/ESA Hubble Space Telescope

 

 

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Subtle distortions hidden in ALMA's stunning image of the gravitational lens SDP.81 are telltale signs that a dwarf dark galaxy is lurking in the halo of a much larger galaxy nearly 4 billion light-years away.

 

This discovery paves the way for ALMA to find many more such objects and could help astronomers address important questions on the nature of dark matter.

 

In 2014, as part of ALMA's Long Baseline Campaign, astronomers studied a variety of astronomical objects to test the telescope's new, high-resolution capabilities. One of these experimental images was that of an Einstein ring, which was produced by the gravity of a massive foreground galaxy bending the light emitted by another galaxy nearly 12 billion light-years away.

 

This phenomenon, called gravitational lensing, was predicted by Einstein's general theory of relativity and it offers a powerful tool for studying galaxies that are otherwise too distant to observe. It also sheds light on the properties of the nearby lensing galaxy because of the way its gravity distorts and focuses light from more distant objects.

 

In a new paper accepted for publication in the Astrophysical Journal, astronomer Yashar Hezaveh at Stanford University in California and his team explain how detailed analysis of this widely publicized image uncovered signs of a hidden dwarf dark galaxy in the halo of the more nearby galaxy.

"We can find these invisible objects in the same way that you can see rain droplets on a window. You know they are there because they distort the image of the background objects," explained Hezaveh. In the case of a rain drop, the image distortions are caused by refraction. In this image, similar distortions are generated by the gravitational influence of dark matter.

 

Current theories suggest that dark matter, which makes up about 80 percent of the mass of the Universe, is made of as-yet-unidentified particles that don't interact with visible light or other forms of electromagnetic radiation. Dark matter does, however, have appreciable mass, so it can be identified by its gravitational influence.

 

For their analysis, the researchers harnessed thousands of computers working in parallel for many weeks, including the National Science Foundation's most powerful supercomputer, Blue Waters, to search for subtle anomalies that had a consistent and measurable counterpart in each "band" of radio data. From these combined computations, the researchers were able to piece together an unprecedented understanding of the lensing galaxy's halo, the diffuse and predominantly star-free region around the galaxy, and discovered a distinctive clump less than one-thousandth the mass of the Milky Way.

 

Because of its relationship to the larger galaxy, estimated mass, and lack of an optical counterpart, the astronomers believe this gravitational anomaly may be caused by an extremely faint, dark-matter dominated satellite of the lensing galaxy. According to theoretical predictions, most galaxies should be brimming with similar dwarf galaxies and other companion objects. Detecting them, however, has proven challenging. Even around our own Milky Way, astronomers can identify only 40 or so of the thousands of satellite objects that are predicted to be present.

 

"This discrepancy between observed satellites and predicted abundances has been a major problem in cosmology for nearly two decades, even called a 'crisis' by some researchers," said Neal Dalal of the University of Illinois, a member of the team. "If these dwarf objects are dominated by dark matter, this could explain the discrepancy while offering new insights into the true nature of dark matter," he added.

 

Computer models of the evolution of the Universe indicate that by measuring the "clumpiness" of dark matter, it's possible to measure its temperature. So by counting the number of small dark matter clumps around distant galaxies, astronomers can infer the temperature of dark matter, which has an important bearing on the smoothness of our Universe.

 

"If these halo objects are simply not there," notes co-author Daniel Marrone of the University of Arizona, "then our current dark matter model cannot be correct and we will have to modify what we think we understand about dark matter particles."

 

This study suggests, however, that the majority of dwarf galaxies may simply not be seen because they're mainly composed of invisible dark matter and emit little if any light. "Our current measurements agree with the predictions of cold dark matter," said team member Gilbert Holder of McGill University in Montreal, Canada. "In order to increase our confidence we will need to look at many more lenses."

 

"This is an amazing demonstration of the power of ALMA," said Hezaveh. "We are now confident that ALMA can efficiently discover these dwarf galaxies. Our next step is to look for more of them and to have a census of their abundance to figure out if there is any possibility of a warm temperature for dark matter particles."

http://spaceref.com/astronomy/dwarf-galaxy-found-lurking-in-another-galaxys-halo.html

 

http://www.eurekalert.org/pub_releases/2016-04/nrao-ddg041416.php

 

Remember this.....

 

Stunning Einstein Ring! Gravitationally-Lensed Galaxy Snapped | Video

video is 1:07 min.

 

 

 

 

Gravitational Lensing (explained)

video is 2:36 min.

 

[LOC Veteran]

Man, so amazing. Reading about some of these things, really puts things in perspective to how small we really are in the universe. Or, how rare and special we might truly be.

[Jim K Global Moderator]

Speaking of galaxies ... a new satellite galaxy to the Milky Way was just discovered in the constellation of Crater.  Given its half-light radius of ∼1100 pc, Crater 2 is the fourth largest satellite of the Milky Way, surpassed only by the Large Magellanic Cloud, Small Magellanic Cloud and the Sagittarius dwarf.

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The galaxy’s empire has a new colony. Astronomers have detected a dwarf galaxy orbiting the Milky Way whose span stretches farther than nearly all other Milky Way satellites. It may belong to a small group of galaxies that is falling into our own.  Giant galaxies like the Milky Way grew large when smaller galaxies merged, according to simulations. The simulations also suggest that whole groups of galaxies can fall into a single giant at the same time. The best examples in our cosmic neighbourhood are the Large and Small Magellanic Clouds, the Milky Way’s two brightest satellites, which probably orbit each other.

 

/snip

 

The galaxy eluded detection for so long because its stars are spread out from one another, giving it a ghostly appearance.  Torrealba says it may not be alone. The Crater 2 dwarf is near four other new-found objects: the Crater globular star cluster as well as three dwarf galaxies in Leo. All may be part of a group that is just now falling into the Milky Way.  Until now, though, the new galaxy has led a quiet life, never venturing near a giant galaxy. We know this because the galaxy is round. If it had encountered a giant, gravity would have bent the dwarf out of shape.

 

More at New Scientist

[Draggendrop Veteran]

Giant Green 'Spider' Invades Stellar Nursery in Eerie New Image

 

The Spider Nebula, shown here using data gathered by NASA’s Spitzer Space Telescope and the 2MASS ground-based survey, lies about 10,000 light-years from Earth and is a site of active star formation.
Credit: NASA/JPL-Caltech/2MASS

 

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An enormous space "spider," glowing a strange and radioactive shade of green, stretches its many legs across the cosmos.

 

But breathe easy, arachnophobes; it's just a photo, and a pretty one at that. The image, which NASA released Thursday (April 14), shows the Spider Nebula, a giant cloud of gas and dust that lies about 10,000 light-years from Earth, in the constellation Auriga.

 

And the spider isn't really green; the photo was created using infrared data gathered by NASA's Spitzer Space Telescope and the Two Micron All-Sky Survey (2MASS). 

 

"In the image, infrared wavelengths, which are invisible to the unaided eye, have been assigned visible colors," NASA officials wrote in an image description. "Light with a wavelength of 1.2 microns, detected by 2MASS, is shown in blue. The Spitzer wavelengths of 3.6 and 4.5 microns are green and red, respectively."

 

Nebulae such as the Spider (which is officially known as IC 417) often serve as stellar nurseries, and there are indeed a number of young stars visible in the photo.

 

"Toward the right of center, against the black background of space, you can see a bright group of stars called 'Stock 8,'" NASA officials wrote. "The light from this cluster carves out a bowl in the nearby dust clouds, seen in the image as green fluff. Along the sinuous tail in the center, and to the left, the groupings of red point sources clumped in the green are also young stars."

 

2MASS was a survey that scanned the heavens between 1997 and 2001 using telescopes in Arizona and Chile (thus providing coverage of the skies in both the Northern and Southern hemispheres).

 

The Spitzer Space Telescope launched in August 2003, kicking off a 2.5-year prime mission. The observatory ran out of helium coolant in 2009, rendering most of its instruments unusable. But Spitzer continues to operate to this day, as part of a more limited "warm" mission.

http://www.space.com/32588-green-spider-nebula-nasa-photo.html

[BetaguyGZT]

Fantastic science coming out of previously "end-of-service" instruments. Hope they can keep HST going the same way -- just because JWST goes up does not mean that HST can't still be useful.

 

In fact, I'd love to see one more Servicing Mission to do some additional upgrades, change out the panels and refill the coolant. HST has been a great instrument and there's no good reason to simply abandon it. AND, I wanna see SpaceX do the Service Mission with Dragon 2.

 

(Hey, I can dream a little, can't I? )

[Draggendrop Veteran]

HAWC Gamma-ray Observatory reveals new look at the very-high-energy sky

 

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The United States and Mexico constructed the High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory to observe some of the most energetic phenomena in the known universe--the aftermath when massive stars die, glowing clouds of electrons around rapidly spinning neutron stars, and supermassive black holes devouring matter and spitting out powerful jets of particles. These violent explosions produce high-energy gamma rays and cosmic rays, which can travel large distances--making it possible to see objects and events far outside our own galaxy.

 

Today, scientists operating HAWC released a new survey of the sky made from the highest energy gamma rays ever observed. The new sky map, which uses data collected since the observatory began running at full capacity last March, offers a deeper understanding of high-energy processes taking place in our galaxy and beyond.

 

"HAWC gives us a new way to see the high-energy sky," said Jordan Goodman, professor of physics at the University of Maryland, and U.S. lead investigator and spokesperson for the HAWC collaboration. "This new data from HAWC shows the galaxy in unprecedented detail, revealing new high-energy sources and previously unseen details about existing sources."

 

HAWC researchers presented the new observation data and sky map April 18, 2016, at the American Physical Society meeting. They also participated in a press conference at the meeting.

 

The new sky map shows many new gamma ray sources within our own Milky Way galaxy. Because HAWC observes 24 hours per day and year-round with a wide field-of-view and large area, the observatory boasts a higher energy reach especially for extended objects. In addition, HAWC can uniquely monitor for gamma ray flares by sources in our galaxy and other active galaxies, such as Markarian 421 and Markarian 501.

 

One of HAWC's new observations provides a better understanding of the high-energy nature of the Cygnus region--a northern constellation lying on the plane of the Milky Way. A multitude of neutron stars and supernova remnants call this star nursery home. HAWC scientists observed previously unknown objects in the Cygnus region and identified objects discovered earlier with sharper resolution.

 

In a region of the Milky Way where researchers previously identified a single gamma ray source named TeV J1930+188, HAWC identified several hot spots, indicating that the region is more complicated than previously thought.

more at the link...

http://www.eurekalert.org/pub_releases/2016-04/uom-hgo041816.php

 

HAWC observations show that a previously known gamma ray source in the Milky Way galaxy, TeV J1930+188, which is probably due to a pulsar wind nebula, is far more complicated than originally thought. Where researchers previously identified a single gamma ray source, HAWC identified several hot spots.
CREDIT
HAWC Collaboration

 

 

This is a view of two-thirds of the entire sky with very-high-energy gamma rays observed by HAWC. Many sources are clearly visible in our own Milky Way galaxy, as well as two other galaxies: Markarian 421 and Markarian 501. Some well-known constellations are shown as a reference. The center of the Milky Way is located toward Sagittarius.
CREDIT
HAWC Collaboration

 

The article covers the installation (massive complex of tanks/detectors) as well as the Cherenkov radiation that is used for triangulation to the source.

 

And before someone pops the "what" ....faster than the speed of light is the reference for the speed of light in water, which is lower than in a vacuum, therefore the Cherenkov radiation emission...ie sort of like a sonic boom.

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NASA Honors Prince by Tweeting Photo of Purple Nebula

 

The famous Crab Nebula, as seen by the Hubble and Herschel space telescopes. NASA tweeted out this photo on April 21, 2016, in honor of the musician Prince, who died that day at the age of 57.
Credit: ESA/Herschel/PACS/MESS Key Programme Supernova Remnant Team; NASA, ESA and Allison Loll/Jeff Hester (Arizona State University)

 

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NASA paid its respects to Prince with a gorgeous space image that recalled the late musician's most famous album, Purple Rain.

 

"A purple nebula, in honor of Prince, who passed away today," NASA officials tweeted Thursday (April 21) along with the photo, a composite view of the Crab Nebula that combines imagery from the agency's iconic Hubble Space Telescope and the European Space Agency's Herschel Space Observatory.

 

The Crab Nebula, which lies about 6,500 light-years from Earth, is a supernova remnant — a structure shaped by the explosive death of a massive star. Such stars burn incredibly brightly and die young, so NASA's photo tribute seems doubly appropriate: Prince, lauded as one of the most talented and influential musicians of his generation, was just 57 when he died.

http://www.space.com/32662-prince-death-nasa-purple-nebula-photo.html

 

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A 'Bubble' for Hubble: Iconic Telescope Snaps Spectacular Birthday Photo

 

This spectacular view of the Bubble Nebula was created from four separate images from the Hubble Space Telescope to mark the observatory's 26th birthday in April 2016. The Bubble Nebula is 10 light-years wide and sculpted by the bright star seen to the left of center.
Credit: NASA, ESA, Hubble Heritage Team

 

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The Hubble Space Telescope may be turning 26 years old this weekend, but its vision is still out of this world. Case in point: this jaw-dropping view of the Bubble Nebula to celebrate the iconic space observatory's birthday.

 

Astronomers unveiled the new Hubble photo today (April 21) to showcase what they billed as a "gigantic cosmic soap bubble" as Hubble nears the anniversary of its launch on April 24, 1990. Scientists also unveiled a spectacular video of the Bubble Nebula as seen by Hubble.

 

"The object, known as the Bubble Nebula, is, in fact, a cloud of gas and dust illuminated by the brilliant star within it," Hubble mission officials wrote in an image description. "The vivid new portrait of this dramatic scene wins the Bubble Nebula a place in the exclusive Hubble hall of fame, following an impressive lineage of Hubble anniversary images." [Astronomers Pick the Hubble's Greatest Space Pictures (Gallery)]

 

Also known as NGC 7635, the Bubble Nebula is a so-called emission nebula located 8,000 light-years from Earth in the direction of the constellation Cassiopeia. The nebula was first discovered in 1787 by famed astronomer William Herschel, and scientists have used Hubble to photograph the object in the past. But those previous views showed only part of the vast nebula.

 

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Hubble's birthday snapshot is actually a combination of four separate images captured by the telescope's Wide Field Camera 3 and pieced together to reveal the entire Bubble Nebula for the first time.

 

"This complete view of the Bubble Nebula allows us to fully appreciate the almost perfectly symmetrical shell which gives the nebula its name," Hubble mission representatives explained in the image description.

 

According to Hubble researchers, "although the sphere already measures around 10 light-years in diameter, it is still growing, owing to the constant pressure of the stellar wind — currently at more than 100,000 kilometers per hour!" That's a mind-boggling rate of expansion of about 62,000 mph.

 

At the nebula's heart is SAO 20575, a star with a mass up to 20 times that of Earth's sun and the source of the stellar wind that is sculpting a bubble in space from the surrounding interstellar dust. The star(which is the bright star just to the left of center in Hubble's view) is also surrounded by formations known as cometary knots (you can see one just to the right of the star). These crescent-shaped dust globules are larger than our entire solar system and as massive as Earth.

 

Hidden in the Bubble Nebula's beauty is an astronomical mystery: Its parent star, SAO 20575, is not at the center of the bubble — a fact that mystifies astronomers.

 

"Astronomers are still discussing why this is the case and how the perfectly round bubble is created nonetheless," Hubble officials wrote.

 

The Bubble Nebula is 8,000 light-years from Earth in the direction of the constellation Cassiopeia. This image shows the nebula (center) and its surrounding region as seen by the Hubble Space Telescope and the Digitized Sky Survey 2.
Credit: NASA, ESA, Digitized Sky Survey; Acknowledgement: Davide De Martin

 

http://www.space.com/32648-hubble-telescope-spectacular-birthday-bubble-image.html

 

Hubble sees a star 'inflating' a giant bubble

http://www.eurekalert.org/pub_releases/2016-04/nsfc-hsa042116.php

 

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Herschel's View of the Galactic Plane

 

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ESA's Herschel mission releases today a series of unprecedented maps of star-forming hubs in the plane of our Milky Way galaxy.

 

This is accompanied by a set of catalogues of hundreds of thousands of compact sources that span all phases leading to the birth of stars in our Galaxy. These maps and catalogues will be very valuable resources for astronomers, to exploit scientifically and for planning follow-up studies of particularly interesting regions in the Galactic Plane.

 

During its four years of operations (2009-2013), the Herschel space observatory scanned the sky at far-infrared and sub-millimetre wavelengths. Observations in this portion of the electromagnetic spectrum are sensitive to some of the coldest objects in the Universe, including cosmic dust, a minor but crucial component of the interstellar material from which stars are born.

 

The Herschel infrared Galactic Plane Survey (Hi-GAL) is the largest of all observing programmes carried out with Herschel, in terms of both observing time over 900 hours of total observations, equivalent to almost 40 days and sky coverage about 800 square degrees, or two percent of the entire sky. Its aim was to map the entire disc of the Milky Way, where most of its stars form and reside, in five of Herschel's wavelength channels: 70, 160, 250, 350 and 500 m.

 

Over the past two years, the Hi-GAL team has processed the data to obtain a series of calibrated maps of extraordinary quality and resolution. With a dynamical range of at least two orders of magnitude, these maps reveal the emission by diffuse material as well as huge filamentary structures and individual, point-like sources scattered across the images.

 

The images provide an unprecedented view of the Galactic Plane, ranging from diffuse interstellar material to denser filamentary structures of gas and dust that fragment into clumps where star formation sets in. They include pre-stellar clumps, protostars in various evolutionary stages and compact cores on the verge of turning into stars, as well as fully-fledged stars and the bubbles carved by their highly energetic radiation.

 

Today, the team releases the first part of this data set, consisting of 70 maps, each measuring two times two degrees, and provided in the five surveyed wavelengths.

 

"These maps are not only stunning from an aesthetic point of view, but they represent a rich data set for astronomers to investigate the different phases of star formation in our Galaxy," explains Sergio Molinari from IAPS/INAF, Italy, Principal Investigator for the Hi-GAL Project.

 

Astronomers have been able to avail of data from Hi-GAL from the very beginning of the observing programme since the team agreed to waive their right to a proprietary period. The observations have been made available through the ESA Herschel Science Archive, including raw data as well as data products generated by systematic pipeline processing. The data has regularly been reprocessed to gradually higher quality and fidelity products.

 

The present release represents an extra step in the data processing. The newly released maps are accompanied by source catalogues in each of the five bands, which can be directly used by the community to study a variety of subjects, including the distribution of diffuse dust and of star-forming regions across the Galactic Plane.

 

The maps cover the inner part of the Milky Way, towards the Galactic Centre as seen from the Sun, with Galactic longitudes between +68 and -70. A second release, with the remaining part of the survey, is foreseen for the end of 2016.

http://spaceref.com/astronomy/herschels-view-of-the-galactic-plane.html

 

Herschel's view of the Galactic Plane

video is 10:09 min.

 

 

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Published on Apr 22, 2016
This video shows a wealth of bright sources, wispy filaments and bubbling nebulas against the background of diffuse gas and dust, marking the spots where stars are being born in the Galaxy.
 

[Draggendrop Veteran]

Kepler resumes science operations

 

NASA's Kepler spacecraft has been on an extended mission called K2 after two of its four reaction wheels failed in 2013. Credit: NASA

 

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WASHINGTON — Two weeks after going into an emergency mode that jeopardized the mission, NASA’s Kepler spacecraft has recovered and resumed normal science operations, the agency announced April 22.

 

In a statement, Charlie Sobeck, the Kepler mission manager, said that the spacecraft had resumed science operations as of 11:30 a.m. Eastern April 22. The spacecraft is now beginning the latest observing campaign for its extended mission, known as K2.

 

Kepler was scheduled to begin those observations earlier in the month, but when spacecraft controllers made contact with the spacecraft April 7 they found the spacecraft was an emergency mode, which NASA describes as the lowest operational mode of the spacecraft. The mission declared a spacecraft emergency to gain priority access to the Deep Space Network to recover the spacecraft.

 

Controllers were able to restore control of Kepler by April 10 and exit emergency mode, gradually bringing back up the spacecraft’s various system. That process found no evidence of damage to the spacecraft, allowing science observations to resume.

 

The cause of the problem that triggered the emergency is still under investigation, but Sobeck said that some kind of “transient event” may have triggered a series of false alarms that overwhelmed the spacecraft’s computers. “Power-cycling the onboard computers and subsystems appears to have cleared the problem,” he said. “We’ve returned to science data collection while the investigation proceeds.”

 

The problem was the most serious issue for Kepler since 2013, when the failure of the second of four reaction wheels on the spacecraft forced it to end its primary mission of observing the same region of the sky four years after its launch. Kepler monitored that region to look for minute variations in the brightness of stars there caused by planets crossing them, allowing astronomers to discover thousands of extrasolar planets.

 

With only two reaction wheels working, Kepler could not point stably enough to continue its primary mission. Engineers, though, developed an alternative pointing approach that allows the spacecraft to point at the same region of the sky for about three months at a time. Kepler started the series of observing campaigns for what is now called the K2 mission in 2014.

 

Prior to the recent problem, project officials said the spacecraft had could operate until 2018. Sobeck didn’t indicate if the anomaly affected the spacecraft’s lifetime.

http://spacenews.com/kepler-resumes-science-operations/

 

The one big question was not answered....how much fuel was consumed during this anomaly?

[Draggendrop Veteran]

Hubble Sees Elegance Concealing an Eventful Past

 

NGC 4111           ESA/Hubble & NASA, Acknowledgement: Judy Schmidt          

 

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The elegant simplicity of NGC 4111, seen here in this image from the NASA/ESA Hubble Space Telescope, hides a more violent history than you might think. NGC 4111 is a lenticular, or lens-shaped, galaxy about 50 million light-years from us in the constellation of Canes Venatici (The Hunting Dogs).

Lenticular galaxies are an intermediate type of galaxy between an elliptical and a spiral. They host aged stars like ellipticals and have a disk like a spiral. However, that’s where the similarities end: They differ from ellipticals because they have a bulge and a thin disk, but are different from spirals because lenticular discs contain very little gas and dust, and do not feature the many-armed structure that is characteristic of spiral galaxies. In this image we see the disc of NGC 4111 edge-on, so it appears as a thin sliver of light on the sky.

 

At first sight, NGC 4111 looks like a fairly uneventful galaxy, but there are unusual features that suggest it is not such a peaceful place. Running through its center, at right angles to the thin disk, is a series of filaments, silhouetted against the bright core of the galaxy. These are made of dust, and astronomers think they are associated with a ring of material encircling the galaxy’s core. Since it is not aligned with the galaxy’s main disc, it is possible that this polar ring of gas and dust is actually the remains of a smaller galaxy that was swallowed up by NGC 4111 long ago.

 

Text credit: European Space Agency
Image credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt

http://www.nasa.gov/image-feature/goddard/2016/hubble-sees-elegance-concealing-an-eventful-past

 

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Cosmic beacons reveal the Milky Way's ancient core

 

The plane of our Galaxy as seen in infrared light from the WISE satellite. (Credit: NOAO/AURA/NSF/AIP/A. Kunder)

 

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An international team of astronomers led by Dr. Andrea Kunder of the Leibniz Institute for Astrophysics Potsdam (AIP) in Germany has discovered that the central 2,000 light-years within the Milky Way galaxy hosts an ancient population of stars. These stars are more than 10 billion years old and their orbits in space preserve the early history of the formation of the Milky Way.

 

For the first time the team kinematically disentangled this ancient component from the stellar population that currently dominates the mass of the central galaxy. The astronomers used the AAOmega spectrograph on the Anglo Australian Telescope near Siding Spring, Australia, and focused on a well-known and ancient class of stars, called RR Lyrae variables.

 

These stars pulsate in brightness roughly once a day, which make them more challenging to study than their static counterparts, but they have the advantage of being "standard candles." RR Lyrae stars allow exact distance estimations and are found only in stellar populations more than 10 billion years old, for example, in ancient halo globular clusters.

 

The velocities of hundreds of stars were simultaneously recorded toward the constellation of Sagittarius over an area of the sky larger than the full Moon. The team therefore was able to use the age stamp on the stars to explore the conditions in the central part of our Milky Way when it was formed.

 

Just as London and Paris are built on more ancient Roman or even older remains, our Milky Way galaxy also has multiple generations of stars that span the time from its formation to the present. Since heavy elements, referred to by astronomers as "metals," are brewed in stars, subsequent stellar generations become more and more metal-rich.

 

Therefore, the most ancient components of our Milky Way are expected to be metal-poor stars. Most of our galaxy's central regions are dominated by metal-rich stars, meaning that they have approximately the same metal content as our Sun, and are arrayed in a football-shaped structure called the "bar."

 

These stars in the bar were found to orbit in roughly the same direction around the galactic center. Hydrogen gas in the Milky Way also follows this rotation. Hence it was widely believed that all stars in the center would rotate in this way.

 

But to the astronomers' astonishment, the RR Lyrae stars do not follow football-shaped orbits, but have large random motions more consistent with their having formed at a great distance from the center of the Milky Way.

 

"We expected to find that these stars rotate just like the rest of the bar," states lead investigator Kunder.

 

Coauthor Juntai Shen of the Shanghai Astronomical Observatory adds, "They account for only one percent of the total mass of the bar, but this even more ancient population of stars appears to have a completely different origin than other stars there, consistent with having been one of the first parts of the Milky Way to form."

 

The RR Lyrae stars are moving targets - their pulsations result in changes in their apparent velocity over the course of a day. The team accounted for this, and was able to show that the velocity dispersion or random motion of the RR Lyrae star population was very high relative to the other stars in the Milky Way's center.

 

The next steps will be to measure the exact metal content of the RR Lyrae population, which gives additional clues to the history of the stars, and enhance by three or four times the number of stars studied, that presently stands at almost 1,000.

http://www.spacedaily.com/reports/Cosmic_beacons_reveal_the_Milky_Ways_ancient_core_999.html

 

Abstract...paper behind a paywall for now.

http://iopscience.iop.org/article/10.3847/2041-8205/821/2/L25#artAbst