Exoplanets in the spotlight at the American Astronomical Society conference

Posted by Sarah Scoles
on Monday, January 06, 2014

Welcome to the American Astronomical Society conference, one of the largest gatherings of astronomers in the history of the planet. Although there are so many planets, it's no longer impressive,” said David Helfand, the president of the society, greeting the more than 3,000 astronomers attending the conference, which is taking place from January 5-9 in Washington, D.C.

Because there's so much information at this conference, I'm providing recaps of the major stories in 140 or fewer words, in my own personal version of Twitter:

The first talk of the day was from Robert Williams, a leader on the Hubble Deep Field project. Created from 150 orbits' worth of observations, the Deep Field is an intimate look at a piece of “blank” sky. But having Hubble stare for so long changed our view: Distant, dim galaxies began to pop out of the darkness. From studying these ultra-distant galaxies, astronomers confirmed dark energy's existence, mapped dark matter, and learned how the cosmos has changed as it's matured – how galaxies were messier, for instance, in the universe's youth. Click here to see the images that inspired 14 more deep surveys from Hubble.

Scott Ransom of the National Radio Astronomy Observatory (NRAO) and collaborators used the Green Bank Telescope to discover a pulsar that orbits a white dwarf every 1.6 days, while a second white dwarf orbits those two every 327 days, all in a space smaller than Earth's orbit. Scientists can use this exotica to test theories of gravity. Watch a video that will may induce a seizure.

In this illustration of Supernova 1987a, the red represents the dust created in the explosion. // Alexandra Angelich (NRAO/AUI/NSF)
Remy Indebetouw of the National Radio Astronomy Observatory (NRAO) and his team went looking for dust – a seemingly straightforward substance whose origin is mysterious. “We have a problem that we have in my house,” Indebetouw said. “There's a lot of dust, and we don't know where it comes from.” They peered into Supernova 1987a, an explosion and aftermath whose evolution scientists have been able to watch in real time, and proved that it created a fourth of Earth's mass in dust. It's the first proof dust comes from supernovae. Learn more.

Alyssa Goodman showed that while the size of your data set does matter, it's how you present it that really makes the difference. You can view her whole talk online and get a roundup of the resources you need to create your own 3-D graphics, generate interactive plots, use an XBOX Kinect to move through a virtual universe, and generally impress your neighbors.

The most common kinds of planets the Kepler spacecraft finds are super-Earths and sub-Neptunes, which can be rocky and Earth-like or have huge gassy atmospheres. // NASA
At the Kepler mission's town hall meeting, officials presented a plan to resurrect the crippled exoplanet hunter, which lost control of two of its reaction wheels. It's called K2, and you can read more about what the phrase “it will use the Sun as a third wheel” means here. Also, if you love flashing plots at parties, check out exoplanetarchive.ipac.caltech.edu, which generates them daily/weekly based on new Kepler data analysis.

Kepler's data also illuminated planets between one and four times as massive as Earth, those known as super-Earths and mini-Neptunes (scientists obviously interpret the wider universe by drawing comparisons to what's nearby). Geoff Marcy of the University of California, Berkeley, discussed the lines between Earth-ish-sized planets that are Earth-like and those that are Earth-ish-sized but totally alien. His team found that if planets are less than two times Earth's size, they tend to be dense and rocky, like Earth. But between two and four times our planet's size, exoplanets have rocky cores, sheaths of water around them, and gassy hydrogen and helium envelopes beyond that.

David Kipping went looking for something a bit smaller: exomoons, or satellites of exoplanets. Instead, he found small planets. And, specifically, the smallest one yet discovered, which has exactly Earth's mass. The planet, called Kepler 314c, is not Earth-like, though: It's 1.6 times as wide, so its overall density is more like that of water, and a thick, gassy atmosphere surrounds it.

Meanwhile, in the atmosphere of planet GJ 1214b, Laura Kreidberg of the University of Chicago found clouds. As in, clouds like the ones you're familiar with. She even made a video about her team's work. Watch it at http://youtu.be/8x2DcgZiKTA and be amazed at how interesting a common terrestrial phenomenon is when you find it on another planet.

Later tonight, I'll be heading to a talk by Neil deGrasse Tyson, so stay tuned tomorrow for reports of some clever quips.

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