Astrobites at AAS 225: Day 4

Thursday was the fourth and final day of the American Astronomical Society winter meeting.

Catch up on Day 1, Day 2, and Day 3.

Many attendees opted to sleep in a bit after about 1000 of us took over a local bar on Wednesday night for the annual unofficial party. Sleepy astronomers aside, there was plenty to see and do on this last day.


Press Conference: Black Holes & Binary Stars

One highlight from the morning press conference was a baffling radio pulsar. These incredibly dense neutron stars appear to “pulse” as they rotate, occasionally sending powerful jets toward our line of sight. So it was a mystery when one such pulsar disappeared without a trace, and reappeared without warning years later. Joeri van Leeuwen shared this mystery with us, and then revealed the explanation. The system is actually composed of two neutron stars orbiting each other, and the gravity is so strong that space is distorted enough for the pulsar’s beam to precess away from our view.


Plenary Talk: Alma Presents a Transformational View of the Universe

Al Wootten, NRAO Scientist and UVa Professor, updated the attendees about ALMA, the Atacama Large Millimeter/Submillimeter Array. He began with a historical overview, followed by a description of the instrument and the driving science goals.

In the remainder of the talk, Al presented highlights from results on distant galaxies ([C II] in z~6 quasars, lensed galaxies, gas outflows from the centers of galaxies), disks in young stars (HL Tau, gas flows across gaps in disks, debris disks), and stellar evolution (Carbon stars, SN1987A) and the solar system (refining the orbit of Pluto for the New Horizons spacecraft, observing the asteroid Juno spin). He concluded by encouraging anyone interested to download and check out ALMA’s science verification images.


Press Conference: Predictions & Probabilities

This session was a bit of a “potpourri,” as it was described by AAS Press Officer Rick Fienberg. Dayton Jones kicked things off by explaining how the Cassini spacecraft and the Very Long Baseline Array (VLBA) here on Earth have measured the location and orbit of Saturn to an accuracy of one mile (at Saturn’s distance from Earth). Measuring better orbits for the planets is used for all kinds of topics in astronomy, including dynamical models of the Solar System, predictions of eclipses, and interplanetary spacecraft navigation. The Juno spacecraft will perform the same measurements on Jupiter’s orbit after it reaches Jupiter in mid-2016.

Next, Adam Miller talked about the challenges astronomy faces now that we’re being flooded with huge amounts of data. He described a project at NASA’s Jet Propulsion Laboratory that uses machine learning algorithms to process the light curve data from over 50 million variable stars coming out of LSST. These algorithms allow us to construct extremely detailed maps of the Milky Way.

Brice Ménard described a gap in our understanding the of the Galaxy. We have made maps of the distribution of atoms, small molecules, dust, and stars in the Galaxy, but it’s hard to detect the large molecules. He then showed a new 3D map of the large molecules in the Galaxy, created by analyzing stellar spectra from the Sloan Digital Sky Survey.

Finally, Robert Nemiroff talked about a fun concept called a “photonic boom.” He described sweeping a laser beam across the surface of the Moon. Due to the finite speed of light and some interesting geometric complications, the spot of light on the Moon’s surface will look like it splits into a pair of spots, moving in opposite directions. Aside from being an interesting thought experiment, this spot-pair creation might be observable in other astronomical systems, and could be used to measure quantities like the orientation of a surface to the Earth, and could lead to another way of measuring distances.

Hack Day

Throughout the day Thursday, several attendees gathered in an out-of-the-way ballroom for a so-called “hack day.” The idea is to pool our skills to work on a project that can largely be completed in one day. At the start of the day, hack ideas were pitched to the room, and participants self-organized into teams. The day was graciously sponsored by LSST and Northrup Grumman, who provided lunch and snacks. Astrobites documented many of these hacks in-progress on twitter, one of which you can experience firsthand once it is finalized in the coming weeks: a revamped astrobites website.



Thanks for following along this week while we brought you news from the 225th AAS  Meeting! We’ll return you to your regularly scheduled astrobites posts next week. There should be a lot of papers showing up on astro-ph now that the meeting is over, so stay tuned!

About Astrobites

This post was written collectively by multiple members of the Astrobites team. Meet the authors of Astrobites.


  1. AAS 227: Day 4 - […] or chunks of larger projects that could be accomplished in a day. Astrobites has written about hack days before.…

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