An image of WISE 1906+4011 from the Kepler Observatory; the green mask marks the location of this faint source.
The Kepler Observatory is uncovering numerous planets in close orbits around distant stars. Now it has a brown dwarf under its belt. A search for nearby cool dwarfs by University of Delaware collaborator John Gizis uncovered the first L dwarf in Kepler, a source that may teach us much about clouds in cool brown dwarfs. Continue reading
Vanderbilt University graduate student Saurav Dhital and collaborators report the discovery an unusually wide low-mass star plus brown dwarf binary. The dim pair of dwarfs, separated by over 100 AU, presents a new challenge to theories describing the formation of very low mass stars and brown dwarfs.
Two for the price of one
Spitzer Science Center colleague Christopher Gelino and I report the identification of low-mass binary system that refuses to show itself. The source, 2MASS J20261584–2943124, is an L dwarf which until now had seemed to be a perfectly unassuming source. However, low-resolution, near-infrared spectroscopy we obtained with the IRTF SpeX spectrograph revealed a peculiar absorption feature that is commonly seen in very low-mass “spectral binaries”, blends of stars with different spectral types. Our analysis indicates that this source is an L dwarf plus T dwarf pair, with a relative brightness of roughly 4 magnitudes (or 40 times fainter) in the near-infrared. We were unable to resolve the putative pair with the Keck Observatory laser guide star adaptive optics system, which rules a binary wider than 9 Astronomical Units (about the distance between the Sun and Saturn). Next step: look for Doppler shifts in the spectrum that would indicate the gravitational influence of the unseen companion and allow us to measure its mass.
This research was published in the Astronomical Journal. Authors include Christopher R. Gelino (Spitzer Science Center) and Adam J. Burgasser (UCSD).
July 2010
