Staring at Kepler's eclipsing binaries
I am Steven, an astronomer from the University of Leuven, Belgium. For 3 nights, I have been observing with the largest telescope of the Calar Alto Observatory. The observatory is located near Almeria, in the south of Spain. On the left side of the picture, you can see the 3.5-m telescope that I am using. The one in the background is slightly smaller and has a mirror of 2.2-m.
I am here to observe binary stars, which are pairs of stars that orbit around each other. All binaries I am observing are eclipsing binaries, which means that every few hours or days, one of the stars passes in front of the other and blocks some of the other's light. They also contain at least one star that is pulsating, just like the stars Katrien wrote about last year.
The stars I am looking at are also being observed by the Kepler satellite, but with the telescope I am looking at them in a different way. I am taking spectra of the stars. On these spectra, the light of the stars is split up in all its different colors. From such spectra, we can learn which kinds of stars are in the binary, for example by determining the stars' temperature and gravity at the surface. Later this month, a colleague of mine is going to look again at the most interesting stars to measure the velocities the stars have due to their orbit in the binary. From that information we will then even be able to tell the masses of the stars!
I have been very lucky with the weather so far, and it looks very promising for the rest of this night and tomorrow as well. I was able to take spectra of more than 50 stars already in the past three nights, which I am going to send to a dozen of colleagues from different countries. They are analyzing the observations that Kepler made of these stars, and my spectra will hopefully help them to learn more about their stars!
In the coming months, I will be traveling to Colorado and South-Africa to attend conferences where all the exciting new discoveries will be announced that people made using Kepler data. From September until December, I will be in California to work together with colleagues from all over the world on the analysis of new Kepler data. I will not have time to spend more nights at the telescope this year, but I will send another postcard when I am observing again on La Palma (Canary Islands, Spain) in 2012!
Postcards from the Observatory