The Last Month in Astronomy

JAN-12-2012 • Favoring Double Degenerates • There are two hypothetical ways that a Type 1a supernova can occur. One is the single degenerate method where a star, a white dwarf, sucks up material from a companion star until it reaches the critical mass needed for a supernova. The other way is called the double degenerate method and it requires two white dwarfs that merge to create the supernova progenitor. Note that the single degenerate method leaves the remains of the companion star behind. The other method does not. Astronomers using the Hubble Space Telescope looked long and hard at SNR 0509-67.5 and no remainder star could be found. This supernova took place 400 years ago. http://www.universetoday.com/92543/hubble-provides-evidence-for-double-degenerate-progenitor-supernova/#more-92543

JAN-11-2012 • Microlensing Finds Many Planets • Microlensing is another method for finding exoplanets. Basically the planets bend distant star light because of their gravity. This method has been used to find how many stars have planets. Basically it comes out to 1-2 planets per every star in the galaxy. That means 100 billion planets in the Milky Way galaxy, conservatively. But this might just be the start. According to UC-Irvine’s Virginia Trimble “I have a list of 17 different ways to find exoplanets and only five have been used so far”. http://www.universetoday.com/92531/microlensing-study-says-every-star-in-the-milky-way-has-planets/

JAN-11-2012 • VLA’s new name • The Very Large Array is an array of radio telescope dishes located in New Mexico. It has been given a new name “The Karl G. Jansky Very Large Array”. Karl Jansky was the father of radio astronomy. The new name will be used when the telescope is rededicated on March 31, 2012. The VLA has been upgraded, increasing its sensitivity by a factor of 10. Jansky died at age 45 but he was the first to discover radio transmissions coming from the center of the Milky Way. http://www.universetoday.com/92520/iconic-telescope-array-gets-a-new-name/

JAN-11-2012 • Planetary system HO scale • The Lionel company helped popularize the O gauge for model railroads (that’s O as in zero except that it is pronouced “oh” in the U.S.). Later, a smaller gauge HO was created - H for Half the size of O gauge. Kepler has found the HO gauge of exoplanetary systems. Three planets all smaller than Earth have been found orbiting a red dwarf star called KOI-961. It’s located in Cygnus and is 120 light-years distant. According to principal investigator John Johnson at Caltech “It’s actually more similar to Jupiter and its moons in scale than any other planetary system.” http://www.msnbc.msn.com/id/45960890/ns/technology_and_science-space/

JAN-07-2012 • 100 Year Starship Crew • The Pentagon’s think tank has selected the group to manage what it calls the 100 Year Starship. The leader will be Mae Jemison, the first black female astronaut. Dr. Jemison has a long list of accomplishments including as a physician and as a Peace Corps volunteer. There is of course one detail that needs to be mentioned, an interstellar spaceship does not exist. In 2014 a design of an interstellar, fusion-propelled spacecraft is expected. The defense department is funding the 100 Year Starship effort with a half-million dollar DARPA grant. http://cosmiclog.msnbc.msn.com/_news/2012/01/07/10035158-skipper-chosen-for-starship-effort

JAN-01-2012 • Grail enters orbit • The lunar spacecraft Grail entered orbit and is now set to start the scientific part of its mission. The two parts will orbit the moon in tandem and it will carefully map gravity inconsistencies to get a better understanding of the moon’s makeup. The spacecraft are in a near polar orbit with each revolution taking 11.5 hours. A number of burns will be done to drop the orbital period to 2 hours. http://www.jpl.nasa.gov/news/news.cfm?release=2012-001

DEC-21-2011 • Brightest Distant Galaxy • Astronomers using the Spitzer and Hubble space telescopes have found a galaxy that is 12.9 billion light-years distant in lookback time. The galaxy designation is GN-108036. This galaxy produces 100 new stars a year. By comparison the Milky Way galaxy makes about 3 stars per year. Yet, the Milky Way is 100 times more massive. http://www.jpl.nasa.gov/news/news.cfm?release=2011-392

DEC-20-2011 • Kepler finds Earth-sized planets • The Kepler mission has discovered the first Earth-sized planet orbiting a sun-like star outside of our solar system. The planets are called Kepler-20e and Kepler-20f. As implied by the names, 3 other planets (b, c and d) have already been discovered around Kepler-20. Those previously discovered planets are closer to Neptune size. The two new planets are much too close to the star to be habitable. Kepler-20e completes one orbit in 6.1 days and it is 87% the size of Earth. Kepler-20f takes 19.6 days and it is 103% the size of Earth. The 3 larger planets have orbits of 3.7, 10.9 and 77.6 days. That means all 5 of these planets are closer to their star as Mercury is to the sun. Still, in 16 years we have gone from not having any evidence of extrasolar planets to finding Earth-sized planets around a sun-like star. The next anticipated milestone is obvious: finding an Earth-sized planet around a sun-like star in an Earth-like orbit. http://www.nasa.gov/mission_pages/kepler/news/kepler-20-system.html