It is always amazing to come to this meeting and take in the sheer number of astronomical papers and results that flow from the world’s investment in cosmic research. Of course I can’t take in all of the hundreds of papers and presentations — it’s impossible. But, I do always give in to a sense of information overload by the end of the first day — and then I come back the next day ready for more, more, more.
So, what was hot in today’s papers at AAS? Here are a few tidbits.
The first press conference a set of observations called the Gemini Deep Deep Survey (GDDS), a set of 50-hour-long observations that showed astronomers how the universe looked and behaved between 8 and 11 billion years ago. What they saw were fully formed, mature galaxies appearing at a time when astronomers expected to see little galaxies crashing together to form larger ones. The implications are still being discussed, but this means that a large number of the stars in the Universe were already in place and maturing when the universe was still only about a billion or so years old. There’s a lot more at the Gemini web site.
Some years ago, a mysterious-seeming object called SS433 took the astronomy world by surprise. It appeared to be a strange thing with jets and a wobble in its orbital motion. Over time astronomers figured out a general explanation for SS433: a binary system with a neutron star or black hole being orbited by a “normal” star that periodically tosses some of its mass away. That material spirals over to the companion, winds up in an accretion disk surrounding it, and then is sprayed away through two powerful jets extending out from the companion. At today’s press conference detailing the latest results, astronomers presented data from observations done using the Very Large Baseline Array and the Chandra X-Ray satellite to describe how the jets “precess” and cause the wobble seen in the object’s orbital motion. While they haven’t completely explained everything about this object, one thing is becoming more clear with each set of observations: the unseen object is a stellar black hole, and its jets are formed by the material it somehow can’t “eat” completely. So, it tosses the stuff away. Images and a movie can be found here.
There’s a star out there that may be the biggest and brightest in the Universe — according to Steve Eikenberry of the University of Florida. It’s called LBV 1806-20, and it’s at least 150 times the mass of the Sun and 5 million times brighter. You’d think we would have spotted something like this before, but it’s been hidden behind a cloud of dust. A 17-member team of astronomers, using several telescopes to gather data, made a series of observations, using infrared studies and other techniques to measure the mass and brightness of the star. The big questions now are: is this really one star, or a cluster of them packed so tightly together that they can’t be distinguished from each other? If it is one star, how did it get so big? While Eikenberry thinks it’s one star, the other question can’t be answered yet, but one thing is clear: stars that get that big don’t last very long because they eat through their fuel at prodigious rates. Wanna see a pic of this stellar behemoth? Visit here.
Okay, that’s it for this installment of “Fun at the AAS Meeting.” I’ll put up another report later on Wednesday.
NOTE: I’ve posted a list of press release stories from Monday and Tuesday sessions here. All links were current as of noon Tuesday, January 6.