A Glimpse of a Brown Dwarf Binary Star System In Motion
When looking up at the night sky, it’s hard to imagine the stationary stars up above are actually continuously moving parts of the universe.
Seven years worth of observational images taken by the Carnegie Astrometric Planet Search Camera (CAPSCam) were compiled to make an animated GIF revealing how a well-known brown dwarf binary system just 12 light-years from Earth, Epsilon Indi B, moves across the sky.
“Understanding the dynamics of this system is important for determining the true masses of the two brown dwarfs in the binary, and therefore important for understanding the nature and evolution of brown dwarfs,” said Alan Boss, a staff scientist at DTM.
Seventeen images from CAPSCam data files, or “fits” images, observed with the du Pont telescope at Las Campanas Observatory in Chile between 5 July 2007 through 17 August 2014, were used to compose this sequence. The CAPSCam science team uses “fits” images to determine how far away the target star is, how fast it is moving (as seen in this sequence), and to look for the wobble of the photocenter of the binary as it moves across the sky. The wobble tells astronomers about the orbital period of the binary, and if there is an unseen third body lurking within its system.
|The bottom of CAPSCam. Photo courtesy of Alan Boss, DTM 2014.|
CAPSCam is a specialized camera designed to search for exoplanets. It was assembled by Ian Thompson (Carnegie Observatories) and his colleagues in Pasadena, CA, and shipped to Chile in 2007. Observations began in March of that year, and have continued on an average of 30 nights each year.
In addition to Boss and Thompson, the science team also includes DTM's Alycia Weinberger. Michael Acierno, DTM and the Geophysical Laboratory IT/IS manager, and Sandra Keiser, DTM senior system administrator, joined the observation team in late 2014.
Although this GIF is not used in Boss’s data analysis, it does demonstrate how CAPSCam can watch nearby stars move across the sky, something that cannot be done by the eye.
Written by Robin A. Dienel, 28 January 2015