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Two Tales from the World of from Big Astronomy

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Astronomy Stories are Cosmic!

Each year about this time, I go stand under a firehose of astronomy information. It’s actually called the American Astronomical Society winter meeting, and it brings together several thousand of the world’s astronomers (not just Americans) to share the latest and greatest in astronomy research.

So, what do we learn at this meeting? Let’s take just take two examples of things I heard about on this first day.

To Pluto…

Pluto mountains
A swatch of mountainous icy terrain on Pluto. Courtesy New Horizons mission.

It began with a Kavli Award talk given by Alan Stern, PI of the New Horizons mission. The view of this distant world as seen by the spacecraft is getting better with each data dump as it sends back mission data across billions of miles as it speeds toward a January 2019 encounter with the Kuiper Belt object 2014 MU69.

Alan’s overview showed that Pluto is an unexpectedly amazing world. For example, the large, heart-shaped Sputnik Planum is distinctly younger than the rest of Pluto’s surface — around only a million years old. This region is, as Alan stated, about the size of Texas and ringed by mountains made of water ice. There is also nitrogen and other ices, but even as cold as it is at Pluto, these ices are about the consistence of cold toothpaste — not something you can build mountains from.  Water ice,  yes — and the flyby data revealed water ice in amounts the team didn’t expect. Yet, there it is, in towering mountains the height of the Rockies in Colorado.

Sputnik Planum is brighter than the rest of the surface of Pluto, and has absolutely NO craters on it — which means that this region is constantly being resurfaced from below. That also implies something is supplying a heat source that melts and softens the ices flowing into the Planum, glacier-like.

The New Horizons team has also found evidence of ice volcanoes on Pluto, something that most of us thought might be there, but with no proof until the mission sent back high-resolution imaqes of intriguing features that do look like volcanic calderas made of ice, and evidence of volatiles (gases) near the vents.

The mission also mapped the Pluto atmosphere, which has distinct haze layers in it; and charted Charon (Pluto’s binary companion), and the smaller moons Nyx, Styx, Kerberos and Hydra. At least two of the smaller moons appear to be smashed-together objects and they spin very rapidly on their axes.

Want to learn more about Pluto? Visit  the New Horizons Web page for more images and info releases.

Astronomy Beyond the Galaxy

astronomy of black holes in galaxy with two black holes
Image of the galaxy SDSS J1126+2944 taken with the Hubble Space Telescope and the Chandra X-ray Observatory. The arrow points to the black hole that lost most of its stars due to gravitational stripping processes.

Now, the second story that intrigued me takes us far out of our own solar system and galaxy.

imagine if you will that you are an astronomer and you’re looking at, oh, say a galaxy called SDSS J1126+2944 using the Hubble Space Telescope and the Chandra X-ray Telescope. Hubble gives you a fine visible-light and near-infrared view of the galaxy, but Chandra reveals something kind of interesting and much more energetic: a pair of black holes at the galaxy’s heart.

One of the black holes is surrounded by stars (as supermassive black holes often are), but the other one is not. In fact, it’s strangely deprived of a stellar “coma”.

Why would that be?

That’s the question that Dr. Julia Comerford of the University of Colorado wants to answer. She’s the one who found the halfway-nekkid black hole, and she described it for us today.

“One black hole is starved of stars, and has 500 times fewer stars associated with it than the other black hole,” she said. “The question is why there’s such a discrepancy.”

One possibility she described is that the galaxy experienced a merger. As the merger went on, the galaxy was subjected to extreme gravitational and tidal forces that stripped away most of the stars from one of the black holes.

The other possibility, however, leads to a rare type of object called an “intermediate” mass black hole. That’s one with a mass of between 100 and 1 million times that of the Sun. Intermediate-mass black holes are predicted to exist at the centers of dwarf galaxies and would have a lower number of associated stars. These intermediate-mass black holes can grow and one day become supermassive black holes. If that’s what happened here, then Comerford has uncovered an object still somewhat rare in the pantheon of galaxy-class black holes.

“Theory predicts that intermediate black holes should exist, but they are difficult to pinpoint because we don’t know exactly where to look,” said Scott Barrows, a postdoctoral researcher at CU-Boulder who co-authored the study. “This unusual galaxy may provide a rare glimpse of one of these intermediate mass black holes.”

If this galaxy does indeed contain an intermediate black hole, it would provide researchers with an opportunity to test the theory that supermassive black holes evolve from these lower-mass ‘seed’ black holes.

There are many more astronomy stories being told at AAS! Stay tuned!

american astronomical society, Gemini Observatory, Orion, Orion Nebula

Bullets of Star Formation

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Clumps of Supersonic Gas Point Back to Hot Young Stars

 

 

This image reveals exquisite details in the outskirts of the Orion Nebula. The large adaptive optics field-of-view (85 arcseconds across) demonstrates the system’s extreme resolution and uniform correction across the entire field. The three filters used for this composite color image include [Fe II], H2, and, K(short)-continuum (2.093 microns) for blue, orange, and white layers respectively. The natural seeing while these data were taken ranged from about 0.8 to 1.1 arcseconds, with AO corrected images ranging from 0.084 to 0.103 arcsecond. Each filter had a total integration (exposure) of 600 seconds. In this image, the blue spots are clouds of gaseous iron “bullets” being propelled at supersonic speeds from a region of massive star formation outside, and below, this image’s field-of-view. As these “bullets” pass through neutral hydrogen gas it heats up the hydrogen and produces the pillars that trace the passage of the iron clouds.
Principal Investigator(s): John Bally and Adam Ginsberg, University of Colorado and the GeMS/GSAOI commissioning team; Data processing/reduction: Rodrigo Carrasco, Gemini Observatory; Color image composite: Travis Rector, University of Alaska Anchorage. Image Courtesy: Gemini Observatory/AURA
The universe is not a static place. Things change all the time. So, the more often you look at an object or process in the cosmos, the more information you’ll get about how it changes over time. Astronomers take advantage of this to get what you might call a “time varying” view of something like the Sun or a planet or a star-forming region (for example). The process gets very interesting when they use newer technology to study something that seems familiar, like the Orion Nebula.

The Gemini Observatory observed a region of the Orion Nebula in 2007 and imaged what are called “bullets”. These almost look like tunnels through the clouds of gas and dust that make up the nebula. They are actually strong winds blowing gas off of massive stars at incredibly high speeds. As these “wind bullets” speed out, they carve out these tubular wakes as much as a fifth of a light-year long.

Those original images were some of the best taken of this region at the time, and they showed dynamic action surrounding hot young stars in the nebula.

Now, the Gemini Observatory has studied these again, this time using an a technology called adaptive optics and laser guide stars to gain a sharp clear image of these bullets in the Orion Nebula. The laser guide stars are artificial stars that are made using a special laser that shoots into the sky and provides astronomers a guide to aim at. They read those stars and use what they see to “adapt” the telescope system to account for the atmospheric aberration between the telescope and the sky. The process provides very clear, almost Hubble-like images, but from the ground.

The new images show more detail and, if you look closely between the originals and the new ones, you can make out a little bit of dynamic motion in the clouds themselves.

Check out the new image here, and then go over to the Gemini page and look at a previous image of the bullets — you can see clear improvements that are giving astronomers a great new tool to check out the Orion Nebula better than ever before.