Detail for Program: GN-2009A-Q-16

Program: GN-2009A-Q-16

Title:

Probing a new substellar temperature regime with the UKIDSS Large Area Survey

PI:

David Pinfield

Co-I(s):

Sandy Leggett, Chris Tinney, Ben Burningham, Nicolas Lodieu, Derek Homeier, Phil Lucas, Paul Dobbie, Daniel Mortlock, Richard Smart, Motohide Tamura, Steve Warren, Cool Dwarf Science Working Group (See http://star-www.herts.ac.uk/~dpi/cdswg.html for full membership)

Abstract

Our UKIDSS/LAS programme is revealing a new substellar population with Teff<700K. New atmospheric physics is anticipated for Teff~400-700K, such as ammonia absorption and/or atmospheric water clouds, and may result in the transition to a new spectral class beyond T (pre-emptively christened Y). This proposal requests 46.5hrs to continue our ToO triggering program with NIRI to spectroscopically examine the growing population of extremely cool LAS T dwarfs. Six T8+ dwarfs have now been found in the LAS, with Teff in the 550-700K range. Some of these objects show possible evidence for ammonia. However, a proper understanding of these atmospheres will only come as our study of a larger sample displaying the spectroscopic sensitivity to a wide range of physical properties (i.e. Teff, logg and [M/H]). In 2009A we will search ~650 sq degs of new LAS sky, and should discover ~50 late T-dwarfs. About 3-5 of these should be T8+.

Publications using this program's data

[data] [ADS] Discovery of the first wide L dwarf + giant binary system and eight other ultracool dwarfs in wide binaries

[data] [ADS] 47 new T dwarfs from the UKIDSS Large Area Survey

[data] [ADS] 76 T dwarfs from the UKIDSS LAS: benchmarks, kinematics and an updated space density

[data] [ADS] The Hawaii Infrared Parallax Program. V. New T-dwarf Members and Candidate Members of Nearby Young Moving Groups