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Adam's Research
[home] [schedule] [cv] [bibliography] [presentations] [blog]My astrophysical research focuses on the observational study of the lowest mass stars and brown dwarfs, specifically the properties of L and T dwarfs. I am particularly interested in studying optical and near-infrared spectral energy distributions, magnetic activity, multiplicity, and population statistics. My work incorporates several observational tools, including optical and infrared spectroscopy, high resolution imaging (including traditional and laser guide star adaptive optics), radio astronomy, space-based (HST & Spitzer) imaging, and photometric monitoring.
T dwarfs
T dwarfs are the coldest brown dwarfs currently known. With surface temperatures below 700oK (400oC, 800oF), these objects have atmospheres more like hot giant planets than stars, containing gases of methane and water as well as clouds. The first T dwarf was discovered in 1995; well over 100 are now known.- Here's an up-to-date list of known T dwarfs maintained at DwarfArchives.org.
- Some near-infrared spectra of T dwarfs and T dwarf spectral standards from the SpeX Prism Spectral Libraries
- T dwarfs were the subject of my Ph.D. Dissertation.
- My discovery work has made substantial use of the 2MASS database. You can download catalog data from Gator and imaging data from the Image Servers.
- I have done substantial work on the classification of T dwarfs using near-infrared and optical spectral data.
Ultracool Subdwarfs
Proper motion surveys have found some of the oldest stars in our Galaxy, stars so old that they were created before our Galaxy was fully enriched with elements heavier than Hydrogen and Helium (what astronomer lump together as "metals"). These so-called halo subdwarfs comprise the first generations of star formation in our Galaxy and trace its early structure. I am interested in finding the coldest examples of halo subdwarfs, so-called ultracool subdwarfs. With the 2MASS survey, we have identified several objects comprising a new class of L subdwarfs, having spectra reminiscent of normal L dwarfs but with fewer metals in their atmospheres. L subdwarfs include the first brown dwarfs to be discovered in the Galactic halo population.- Some near-infrared spectra of ultracool subdwarfs from the SpeX Prism Spectral Libraries
- The coldest known halo subdwarf, 2MASS 0532+8246, is also the first confirmed halo brown dwarf.
- Read my recent review article presented at the Cool Stars 13 meeting in Hamburg, Germany.
- Coming soon, a ultracool subdwarf repository!
Press!
- More Weather on Brown Dwarfs (2006 July 3):
[Space.com] - NIRSPEC Spectroscopic Survey (2003 September 3):
[UCLA Press Release] - T Dwarf Binaries (2002 June 3):
[UCLA Press Release] - Weather on Brown Dwarfs (2002 May 23):
[NASA Ames Release] [CNN.com] - Gliese 570D (2000 January 15):
[2MASS Release] [CTIO Release (en espanol)] [Space.com]
It even made history! - First T Dwarf Discoveries (1999 June 1):
[NASA Press Release] [NY Times] [CNN.com]
Other Links
- Ph.D. Dissertation [PDF]
- Bibliography [PDF] [ADS]
- The 2MASS/NStars Rare Objects Team: Peter Allen (U. Penn), Adam Burrows (U. Arizona), Kelle Cruz (AMNH), John Gizis (U. Delaware), J. Davy Kirkpatrick (IPAC/Caltech), James Liebert (U. Arizona), & I. Neill Reid (STScI).
- DwarfArchives.org maintained by Chris Gelino, Davy Kirkpartick and myself
- Very Low Mass Binary Archive maintained by Nick Siegler
- SpeX Prism Spectral Libraries maintained by me
Adam J. Burgasser
ajb [at] mit [dot] edu