Description of August 6th Radio Show: Star Formation and Brown Dwarfs

I know I already posted the August 6th radio show here, but below is a detailed description of what I actually talked about:

• Mars Phoenix Lander: The Thermal and Evolved Gas-Analyzer (TEGA) instrument detects water in sub-surface Martian ice it analyzed, mission also extended until September 30th (link); Microscopy, Electro-chemistry, and Conductivity Analyzer (MECA) instrument possibly detects perchlorate.
• News: Liquid lake discovered on Titan, believed to be full of ethane; European Space Agency (ESA) spacecraft Mars Express takes highest resolution image of Mars's moon Phobos ever (link); ESA spacecraft Rosetta starts tracking asteroid (2867) Steins in order to rendezvous with it on 5 September; book review in Nature on "The Black Hole War" by Leonard Susskind describing a debate between him and Stephen Hawking on the fate of black holes; NY Times article about new book "The Universe Mirror" by Robert Zimmerman about the challenges in getting the Hubble Space Telescope built and launched; congratulations to Mr. Enrico Saggese for being appointed head of the Italian Space Agency; congrats to Dr. Thomas B. Irvine for being appointed Deputy Associate Administrator of NASA's Aeronautics Research Mission Directorate; congratulation to the winners of NASA's first Aeronautics Scholarship competition - list of winners available here and more about this program available here; NASA unveils this webpage in honor of its 50th anniversary; NASA hosts an international meeting to discuss future lunar science missions, signs partnership agreement with University of Western Ontario; NASA's Lunar Reconnaissance Orbiter undergoes pre-launch testing at Goddard Space Flight Center; Solar Eclipse on morning of August 1 (link); NASA to broadcast highlights of its activity in HD on NASA TV.
• Calendar of upcoming Astronomy/science events in the greater New York City / Poughkeepsie Area.
• Star Formation: As described very well in an interview I did with Dr. Aki Roberge of NASA's Goddard Space Flight Center, stars form by the gravitational collapse of dense clumps (>100 of atoms per cubic cm) of material in molecular clouds, cold regions where atoms can stick together into molecules and dust grains (essentially, very large molecules with 100s of atoms stuck together). Therefore, the chemical composition of these molecular clouds are the building blocks of the chemicals we find in the Sun, Solar System, and on Earth. With radio telescopes, one can see spectral lines from these molecules, and in one molecular cloud, a primitive amino acid (acetonitrile) was discovered, while surveys for identifying other complicated molecules in molecular clouds are currently taking place (link). Miniature diamonds found inside meteorites can also form in these molecular clouds, and can be detected with the Spitzer Space Telescope. To determine how a molecular cloud breaks into dense clumps which will collapse into stars, it is important to know the distribution of material inside the molecular cloud. Since molecular clouds are extremely dense and cold, it is very hard to see into them because they absorb all the optical light behind them and don't emit much optical light of their own. However, molecular clouds scatter infrared light from stars behind them, and this scattered light can be observed, creating an effect called "cloud shine". Since denser regions scatter more light, the amount scattered light which one sees gives an estimate of the density. This approach is currently being applied to a large number of molecular clouds with ESO's New Technology Telescope and upcoming VISTA telescope. As clumps in the molecular cloud collapse into stars, these clumps can fragment, and the mass of these fragments are extremely important in determining the mass of the stars which form. Recent computer simulations by Dr. Krumholz and Prof. McKee of Princeton University suggest that, to form the most massive stars, the clump must have column density (density of material through the region, mass per unit area NOT mass per unit volumn) 1 gm / square centimeter, though this number depends on fraction of mass in elements heavier than H and He which are critical in the physics of how the gas increases in density by about a million times to become a star. Replicated this process on a computer is extremely difficult, and recently a new software code called "FEARLESS" has been developed to try and solve many of the problems (link). As the gas collapses into star, it doesn't collapse directly into a star but forms a disk of material which slowly moves inward to for the star. Recent observations of a forming star, DG Tau, has found collimated, fast moving material moving away from the central star which astronomer call a "jet". Many of these "jets" from forming star have been discovered, but the material in this one is so hot it produces X-rays that are absorbed by the material in the disk, possibly changing its chemical composition. Now, stars born at the same time, with the same mass, and out of the same material are expected to have identical properties. However, recent observations of a binary star system where one star passes in front of the other suggest that, despite having the same mass and age, they have different temperatures and radii which is extremely bizarre (link).
• Brown Dwarfs: Brown dwarfs are the least massive stars, only a few times more massive than Jupiter, and are believed to have too little mass to produce a hot core that fuses hydrogen into helium as out Sun does. As mentioned above, stars when they are form are often observed to power jets into their surroundings. Well, brown dwarfs were recently observed to do the same (link). Also, the coldest dwarf ever observed was recently detected, with a surface temperature of 350 Celsius, comparable to a pizza oven, and about 3x times colder than the surface of the Sun (link). Also, the mass and temperature of brown dwarfs orbiting each other have recently been measured, and differ from that predicted by models (link).

Sorry for the delay in posting this, and hope you enjoy. As always, any and all feedback will be very appreciated.