Faherty, Jacqueline K., Burgasser, Adam J., West, Andrew A., Bochanski, John J., Cruz, Kelle L., Shara, Michael M., ...
We report on nine wide common proper motion systems containing late-type M, L, or T companions. We confirm six previously reported companions, and identify three new systems. The ages of these...
Cloud Formation and Dynamics in Cool Dwarf and Hot Exoplanetary Atmospheres (2009)
The lowest-mass stars, brown dwarfs and extrasolar planets present challenges and opportunities for understanding dynamics and cloud formation processes in low-temperature atmospheres. For brown...
MASE: A New Data--Reduction Pipeline for the Magellan Echellette Spectrograph (2009)
Bochanski, John J., Hennawi, Joseph F., Simcoe, Robert A., Prochaska, J. Xavier, West, Andrew A., Burgasser, Adam J., ...
We introduce a data reduction package written in Interactive Data Language (IDL) for the Magellan Echellete Spectrograph (MAGE). MAGE is a medium-resolution (R ~4100), cross-dispersed, optical...
Burgasser, Adam J., Dhital, Saurav, West, Andrew
We report the identification of 2MASS J15500845+1455180 as a 0"9 L dwarf visual binary. This source is resolved in Sloan Digital Sky Survey (SDSS) images and in near-infrared imaging with the IRTF...
2MASS J06164006−6407194: the first outer halo L subdwarf (2009)
Cushing, Michael C., Looper, Dagney, Burgasser, Adam J., Kirkpatrick, J. Davy, Faherty, Jacqueline
We present the serendipitous discovery of an L subdwarf in the Two Micron All Sky Survey (2MASS) J06164006–6407194, in a search of the 2MASS for T dwarfs. Its spectrum exhibits features indicative...
An Age Constraint for the Very Low-Mass Stellar/Brown Dwarf Binary 2MASS J03202839-0446358AB (2009)
Burgasser, Adam J., Blake, Cullen H.
2MASS J03202839-0446358AB is a recently identified, late-type M dwarf/T dwarf spectroscopic binary system for which both the radial velocity orbit for the primary and spectral types for both...
The Brown Dwarf-Exoplanet Connection (2009)
Brown dwarfs are commonly regarded as easily-observed templates for exoplanet studies, with comparable masses, physical sizes and atmospheric properties. There is indeed considerable overlap in the...
Optical and Near-Infrared Spectroscopy of the L Subdwarf SDSS J125637.13-022452.4 (2009)
Burgasser, Adam J., Witte, Soeren, Helling, Christiane, Sanderson, Robyn E., Bochanski, John J., Hauschildt, Peter H.
Red optical and near-infrared spectroscopy are presented for SDSS J125637.13-022452.4, one of only four L subdwarfs reported to date. These data confirm the low-temperature, metal-poor nature of this...
Toward the End of Stars: Discovering the Galaxy's Coldest Brown Dwarfs (2009)
Burgasser, Adam J., Bloom, Josh, Cruz, Kelle, Cushing, Michael, Leggett, Sandy, Lodders, Katharina, ...
This White Paper to the National Academy of Sciences Astro2010 Decadal Review Committee highlights cross-disciplinary science opportunities over the next decade with cold brown dwarfs, sources...
Cruz, Kelle L., Kirkpatrick, J. Davy, Burgasser, Adam J.
We present an analysis of 23 L dwarfs whose optical spectra display unusual features. Twenty-one were uncovered during our search for nearby, late-type objects using the Two Micron All Sky Survey,...
Faherty, Jacqueline K., Burgasser, Adam J., Cruz, Kelle L., Shara, Michael M., Walter, Frederick M., Gelino, Christopher R.
We report proper-motion measurements for 427 late-type M, L, and T dwarfs, 332 of which have been measured for the first time. Combining these new proper motions with previously published...
Kirkpatrick, J. Davy, Cruz, Kelle L., Barman, Travis S., Burgasser, Adam J., Looper, Dagny L., Tinney, C. G., ...
Using a large sample of optical spectra of late-type dwarfs, we identify a subset of late-M through L field dwarfs that, because of the presence of low-gravity features in their spectra, are believed...
2MASS J09393548–2448279: The coldest and least luminous brown dwarf binary known? (2008)
Burgasser, Adam J., Tinney, C. G., Cushing, Michael C., Saumon, Didier, Marley, Mark S., Bennett, Clara S., ...
Determinations of the luminosity and atmospheric properties of the T8 brown dwarf 2MASS J09393548 - 2448279 are presented, based on Spitzer IRAC and IRS observations and ground-based astrometry. We...
Using Magnetic Activity and Galactic Dynamics to Constrain the Ages of M Dwarfs (2008)
West, Andrew A., Hawley, Suzanne L., Bochanski, John J., Covey, Kevin R., Burgasser, Adam J.
We present a study of the dynamics and magnetic activity of M dwarfs using the largest spectroscopic sample of low-mass stars ever assembled. The age at which strong surface magnetic activity (as...
Cruz, Kelle L., Kirkpatrick, J. Davy, Burgasser, Adam J.
We present an analysis of 23 L dwarfs whose optical spectra display unusual features. Twenty-one were uncovered during our search for nearby, late-type objects using the Two Micron All-Sky Survey...
Observation and modelling of dusty, low gravity L, and M dwarfs (2008)
Seifahrt, Andreas, Helling, Christiane, Burgasser, Adam J., Allers, Katelyn N., Cruz, Kelle L., Cushing, Michael C., ...
Observational facilities allow now the detection of optical and IR spectra of young M- and L-dwarfs. This enables empirical comparisons with old M- and L- dwarfs, and detailed studies in comparison...
Brown Dwarfs as Galactic Chronometers (2008)
Brown dwarfs are natural clocks, cooling and dimming over time due to insufficient core fusion. They are also numerous and present in nearly all Galactic environments, making them potentially useful...
Looper, Dagny L., Kirkpatrick, J. Davy, Cutri, Roc M., Barman, Travis, Burgasser, Adam J., Cushing, Michael C., ...
We present the discovery of two nearby L dwarfs from our 2MASS proper-motion search, which uses multiepoch 2MASS observations covering ~4700 deg^2 of sky. 2MASS J18212815+1414010 and 2MASS...
Ultracool Subdwarfs: The Halo Population Down to the Substellar Limit (2008)
Burgasser, Adam J., Lepine, Sebastien, Lodieu, Nicolas, Scholz, Ralf-Dieter, Delorme, Phillippe, Jao, Wei-Chun, ...
Ultracool subdwarfs are low luminosity, late-type M and L dwarfs that exhibit spectroscopic indications of subsolar metallicity and halo kinematics. Their recent discovery and ongoing investigation...
Clouds, Brightening and Multiplicity Across the L Dwarf/T Dwarf Transition (2008)
The transition between the two lowest-luminosity spectral classes of brown dwarfs--the L dwarfs and T dwarfs--is traversed by nearly all brown dwarfs as they cool over time. Yet distinct features of...
Discovery of a T dwarf binary with the largest known J-band flux reversal (2008)
Looper, Dagny L., Gelino, Christopher R., Burgasser, Adam J., Kirkpatrick, J. Davy
We present Keck laser guide star observations of two T2.5 dwarfs-2MASS J11061197+2754225 and 2MASS J14044941-3159329-using NIRC2 on Keck II and find 2MASS J14044941-3159329 to be a 0.13" binary. This...
Faherty, Jacqueline K., Burgasser, Adam J., Cruz, Kelle L., Shara, Michael M., Walter, Frederick M., Gelino, Christopher R.
We report proper motion measurements for 427 late-type M, L and T dwarfs, 332 of which have been measured for the first time. Combining these new proper motions with previously published measurements...
Kirkpatrick, J. Davy, Cruz, Kelle L., Barman, Travis S., Burgasser, Adam J., Looper, Dagny L., Tinney, C. G., ...
Using a large sample of optical spectra of late-type dwarfs, we identify a subset of late-M through L field dwarfs that, because of the presence of low-gravity features in their spectra, are believed...
Burgasser, Adam J., Liu, Michael C., Ireland, Michael J., Cruz, Kelle L., Dupuy, Trent J.
Evidence is presented that 2MASS J03202839–0446358, a late-type dwarf with discrepant optical (M8:) and near-infrared (L1) spectral types, is an as-yet unresolved stellar/brown dwarf binary with...
Looper, Dagny L., Kirkpatrick, J. Davy, Cutri, Roc M., Barman, Travis, Burgasser, Adam J., Cushing, Michael C., ...
We present the discovery of two nearby L dwarfs from our 2MASS proper motion search, which uses multi-epoch 2MASS observations covering ~4700 square degrees of sky. 2MASS J18212815+1414010 and 2MASS...
Burgasser, Adam J., Liu, Michael C., Ireland, Michael J., Cruz, Kelle L., Dupuy, Trent J.
Evidence is presented that 2MASS J03202839-0446358, a late-type dwarf with discrepant optical (M8:) and near-infrared (L1) spectral types, is an as-yet unresolved stellar/brown dwarf binary with...
Clouds, Gravity, and Metallicity in Blue L Dwarfs: The Case of 2MASS J11263991–5003550* (2008)
Burgasser, Adam J., Looper, Dagny L., Kirkpatrick, J. Davy, Cruz, Kelle L., Swift, Brandon J.
Optical and near-infrared spectroscopy of the newly discovered peculiar L dwarf 2MASS J11263991–5003550 are presented. Folkes et al. classified this source as a high proper motion L9±1 dwarf based...
L-dwarf binaries in the 20-parsec sample (2008)
Reid, I. Neill, Cruz, K. L., Burgasser, Adam J., Liu, Michael C.
We have used the NICMOS NIC1 camera on the Hubble Space Telescope to obtain high-resolution near-infrared images of 27 nearby ultracool dwarfs with formal distance estimates less than 20 parsecs. One...
Adam J. Burgasser, J. Davy Kirkpatrick, Michael E. Brown, I. Neill Reid, Adam Burrows, James Liebert, ...
We present near-infrared spectra for a sample of T dwarfs, including 11 new discoveries made using the 2 Micron All Sky Survey. These objects are distinguished from warmer (L-type) brown dwarfs by...
J. Davy Kirkpatrick, I. Neil Reid, James Liebert, John E. Gizis, Adam J. Burgasser, G. Monet, ...
We present JHK, photometry, far red spectra, and spectral classifications for an additional 67 L dwarfs discovered by the Two Micron All Sky Survey. One of the goals of this new search was to locate...
Adam J. Burgasser, J. Davy Kirkpatrick, I. Neill Reid, James Liebert, John E. Gizis, Michael E. Brown
We report the detection of Hff emission in the T dwarf (methane brown dwarf) 2MASSW J1237392+652615 over three days using the Keck Low Resolution Imaging Spectrograph. The measured line flux, log(L...
Clouds, Gravity and Metallicity in Blue L dwarfs: The Case of 2MASS J11263991-5003550 (2007)
Burgasser, Adam J., Looper, Dagny L., Kirkpatrick, J. Davy, Cruz, Kelle L., Swift, Brandon J.
Optical and near-infrared spectroscopy of the newly discovered peculiar L dwarf 2MASS J11263991-5003550 are presented. Folkes et al. identified this source as a high proper motion L9+/-1 dwarf based...
Looper, Dagny L., Burgasser, Adam J., Kirkpatrick, J. Davy, Swift, Brandon J.
We report the discovery of a fifth candidate substellar system in the ~5-10 Myr TW Hydrae Association - DENIS J124514.1-442907. This object has a NIR spectrum remarkably similar to that of 2MASS...
Parallax and Luminosity Measurements of an L Subdwarf (2007)
Burgasser, Adam J., Vrba, Frederick J., Lépine, Sébastien, Munn, Jeffrey A., Luginbuhl, Christian B., Henden, Arne A., ...
We present the first parallax and luminosity measurements for an L subdwarf, the sdL7 2MASS J05325346+8246465. Observations conducted over three years by the USNO infrared astrometry program yield an...
Looper, Dagny L., Kirkpatrick, J. Davy, Burgasser, Adam J.
We present the discovery of 11 new T dwarfs, found during the course of a photometric survey for mid-to-late T dwarfs in the 2MASS Point Source Catalog and from a proper-motion-selected sample of...
SDSS J080531.84+481233.0: An Unresolved L Dwarf/T Dwarf Binary (2007)
SDSS J080531.84+481233.0 is a peculiar L-type dwarf that exhibits unusually blue near-infrared and mid-infrared colors and divergent optical (L4) and near-infrared (L9.5) spectral classifications....
Looper, Dagny L., Kirkpatrick, J. Davy, Burgasser, Adam J.
We present the discovery of 11 new T dwarfs, found during the course of a photometric survey for mid-to-late T dwarfs in the 2MASS Point Source Catalog and from a proper motion selected sample of...
A New Population of Young Brown Dwarfs (2007)
Cruz, Kelle L., Kirkpatrick, J. Davy, Burgasser, Adam J., Looper, Dagny, Mohanty, Subhanjoy, Prato, Lisa, ...
We report the discovery of a population of late-M and L field dwarfs with unusual optical and near-infrared spectral features that we attribute to low gravity -- likely uncommonly young, low-mass...
Cruz, Kelle L., Reid, I. Neill, Kirkpatrick, J. Davy, Burgasser, Adam J., Liebert, James, Solomon, Adam R., ...
We present a 20 pc, volume-limited sample of M7-L8 dwarfs created through spectroscopic follow-up of sources selected from the Two Micron All Sky Survey Second Incremental Release Point Source...
Discovery of a 66 mas Ultracool Binary with Laser Guide Star Adaptive Optics (2007)
Siegler, Nick, Close, Laird M., Burgasser, Adam J., Cruz, Kelle L., Marois, Christian, Macintosh, Bruce, ...
We present the discovery of 2MASS J21321145+1341584AB as a closely separated (0.066") very low-mass field dwarf binary resolved in the near-infrared by the Keck II Telescope using laser guide star...
Ultracool Subdwarfs: Subsolar Metallicity Objects Down to Substellar Masses (2007)
In the past few years, astronomers have uncovered several very low-temperature, metal-poor stars with halo or thick disk kinematics and peculiar spectral and photometric properties, so-called...
McLean, Ian S., Prato, L., McGovern, Mark R., Burgasser, Adam J., Kirkpatrick, J. Davy, Rice, Emily L., ...
We present a sequence of high resolution (R~20,000 or 15 km/s) infrared spectra of stars and brown dwarfs spanning spectral types M2.5 to T6. Observations of 16 objects were obtained using eight...
Discovery of a High Proper Motion L Dwarf Binary: 2MASS J15200224-4422419AB (2006)
Burgasser, Adam J., Looper, Dagny L., Kirkpatrick, J. Davy, Liu, Michael C.
We report the discovery of the wide L1.5+L4.5 binary 2MASS J15200224-4422419AB, identified during spectroscopic followup of high proper motion sources selected from the Two Micron All Sky Survey....
The Physical Properties of HD 3651B: An Extrasolar Nemesis? (2006)
I present detailed analysis of the near infrared spectrum of HD 3651B, a faint, co-moving wide companion to the nearby planet-hosting star HD 3651. These data confirm the companion as a brown dwarf...
Binaries and the L Dwarf/T Dwarf Transition (2006)
High-resolution imaging has revealed an unusually high binary fraction amongst objects spanning the transition between the L dwarf and T dwarf spectral classes. In an attempt to reproduce and unravel...
Optical Spectroscopy of 2MASS Color-Selected Ultracool Subdwarfs (2006)
Burgasser, Adam J., Cruz, Kelle L., Kirkpatrick, J. Davy
We present Gemini GMOS and Magellan LDSS-3 optical spectroscopy for seven ultracool subdwarf candidates color-selected from the Two Micron All Sky Survey. Five are identified as late-type subdwarfs,...
On the Nature of the Unique H$\alpha$-Emitting T Dwarf 2MASS J12373919+6526148 (2006)
Liebert, James, Burgasser, Adam J.
We explore and discount the hypothesis that the strong, continual H$\alpha$-emitting T dwarf 2MASS J12373919+6526148 can be explained as a young, low gravity, very low mass brown dwarf. The source is...
Cruz, Kelle L., Reid, I. Neill, Kirkpatrick, J. Davy, Burgasser, Adam J., Liebert, James, Solomon, Adam R., ...
We present a 20-pc, volume-limited sample of M7-L8 dwarfs created through spectroscopic follow-up of sources selected from the Two Micron All Sky Survey (2MASS) Second Incremental Release Point...
The Spectrum of HD 3651B: An Extrasolar Nemesis? (2006)
This article has been withdrawn; see astro-ph/0611542
Resolved Spectroscopy of M Dwarf/L Dwarf Binaries. II. 2MASS J 17072343-0558249AB (2006)
McElwain, Michael W., Burgasser, Adam J.
We present IRTF SpeX observations of the M/L binary system 2MASS J17072343-0558249. SpeX imaging resolves the system into a 1"01+/-0.17 visual binary in which both components have red near infrared...
A search for binary systems among the nearest L dwarfs (2006)
Reid, I. N., Lewitus, E., Allen, P. R., Cruz, Kelle L., Burgasser, Adam J.
We have used the NICMOS NIC1 camera on the Hubble Space Telescope to obtain high angular resolution images of 51 ultracool dwarfs in the immediate Solar Neighbourhood. Nine systems are resolved as...
Burgasser, Adam J., Kirkpatrick, J. Davy, Cruz, Kelle L., Reid, I. Neill, Leggett, Sandy K., Liebert, James, ...
We present the results of a Hubble Space Telescope NICMOS imaging survey of 22 T-type field brown dwarfs. Five are resolved as binary systems with angular separations of 0"05-0"35, and companionship...
Discovery of the Coolest Extreme Subdwarf (2006)
Burgasser, Adam J., Kirkpatrick, J. Davy
We report the discovery of LEHPM 2-59 as the coolest extreme M subdwarf (esdM) found to date. Optical and near infrared spectroscopy demonstrate that this source is of later spectral type than the...
Burgasser, Adam J., Reid, I. Neill, Siegler, Nick, Close, Laird, Allen, Peter, Lowrance, Patrick, ...
The properties of multiple stellar systems have long provided important empirical constraints for star formation theories, enabling (along with several other lines of evidence) a concrete,...
Adam J. Burgasser, J. Davy Kirkpatrick, Kelle L. Cruz, I. Neill Reid, Y K. Leggett, James Liebert, ...
We present the results of a Hubble Space Telescope NICMOS imaging survey of 22 T-type field brown dwarfs. Five are resolved as binary systems with angular separations of 0B05Y0B35, and companionship...
Discovery of a Very Young Field L Dwarf, 2MASS J01415823-4633574 (2005)
Kirkpatrick, J. Davy, Barman, Travis S., Burgasser, Adam J., McGovern, Mark R., McLean, Ian S., Tinney, Christopher G., ...
While following up L dwarf candidates selected photometrically from the Two Micron All Sky Survey, we uncovered an unusual object designated 2MASS J01415823-4633574. Its optical spectrum exhibits...
A Method for Determining the Physical Properties of the Coldest Known Brown Dwarfs (2005)
Burgasser, Adam J., Burrows, Adam, Kirkpatrick, J. Davy
We present a method for measuring the physical parameters of the coldest T-type brown dwarfs using low resolution near infrared spectra. By comparing H_2O- and H_2-sensitive spectral ratios between...
Resolved Spectroscopy of M Dwarf/L Dwarf Binaries. I. DENIS J220002.05-303832.9AB (2005)
Burgasser, Adam J., McElwain, Michael W.
We present the discovery of the common proper motion M9 + L0 binary DENIS J220002.05-303832.9AB, identified serendipitously with the SpeX near infrared imager/spectrograph. Spectral types are derived...
SDSS J042348.57-041403.5AB: A Brown Dwarf Binary Straddling the L/T Transition (2005)
Burgasser, Adam J., Reid, I. Neill, Leggett, S. K., Kirkpatrick, J. Davy, Liebert, James, Burrows, Adam
We present the discovery of SDSS J042348.57-041403.5 as a closely-separated (0"16) brown dwarf binary, resolved by the Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrometer....
A Unified Near Infrared Spectral Classification Scheme for T Dwarfs (2005)
Burgasser, Adam J., Geballe, T. R., Leggett, S. K., Kirkpatrick, J. Davy, Golimowski, David A.
A revised near infrared classification scheme for T dwarfs is presented, based on and superseding prior schemes developed by Burgasser et al. and Geballe et al., and defined following the precepts of...
The 2MASS Wide-Field T Dwarf Search. V. Discovery of a T Dwarf via Methane Imaging (2005)
Ellis, S. C., Tinney, C. G., Burgasser, Adam J., Kirkpatrick, J. Davy, McElwain, Michael W.
We present the discovery of a T dwarf, 2M2151-4853, via differential imaging through methane filters. The filters are designed to highlight the strong absorption in the H band, due to methane found...
The 2MASS Wide-Field T Dwarf Search. IV Unting out T dwarfs with Methane Imaging (2005)
Tinney, C. G., Burgasser, Adam J., Kirkpatrick, J. Davy, McElwain, Michael W.
We present first results from a major program of methane filter photometry for low-mass stars and brown dwarfs. The definition of a new methane filter photometric system is described. A recipe is...
Multiplicity Amongst Wide Brown Dwarf Companions to Nearby Stars: Gliese 337CD (2005)
Burgasser, Adam J., Kirkpatrick, J. Davy, Lowrance, Patrick J.
We present Lick Natural Guide Star Adaptive Optics observations of the L8 brown dwarf Gliese 337C, which is resolved for the first time into two closely separated (0"53+/-0"03), nearly equal...
Spitzer Studies of Ultracool Subdwarfs: Metal-poor Late-type M, L and T Dwarfs (2005)
Recent discoveries from red optical proper motion and wide-field near-infrared surveys have uncovered a new population of ultracool subdwarfs, metal-poor stars and brown dwarfs extending into the...
Burgasser, Adam J., Putman, Mary E.
We report the results of a radio monitoring program conducted at the Australia Telescope Compact Array to search for quiescent and flaring emission from seven nearby Southern late-type M and L...
Burgasser, Adam J., Kirkpatrick, J. Davy, Lepine, Sebastien
Recent discoveries from red optical proper motion and wide-field near-infrared surveys have uncovered a new population of ultracool subdwarfs -- metal-poor stars and brown dwarfs extending into the...
Discovery of a Second L Subdwarf in the Two Micron All Sky Survey (2004)
I report the discovery of the second L subdwarf identified in the Two Micron All Sky Survey, 2MASS J16262034+3925190. This high proper motion object (mu = 1.27+/-0.03 "/yr) exhibits near-infrared...
T Dwarfs and the Substellar Mass Function. I. Monte Carlo Simulations (2004)
Monte Carlo simulations of the field substellar mass function (MF) are presented. Starting from various representations of the MF below 0.1 M$_{\sun}$ and the stellar birth rate, luminosity functions...
The 2MASS Wide-Field T Dwarf Search. III. Seven New T Dwarfs and Other Cool Dwarf Discoveries (2004)
Burgasser, Adam J., McElwain, Michael W., Kirkpatrick, J. Davy, Cruz, Kelle L., Tinney, Chris G., Reid, I. Neill
We present the discovery of seven new T dwarfs identified in the Two Micron All Sky Survey. Low-resolution (R$\sim$150) 0.8--2.5 micron spectroscopy obtained with the IRTF SpeX instrument reveal the...
2MASS J05185995-2828372: Discovery of an Unresolved L/T Binary (2004)
Cruz, Kelle L., Burgasser, Adam J., Reid, I. Neill, Liebert, James
We present the peculiar near-infrared spectrum of the newly discovered brown dwarf 2MASS J05185995-2828372, identified in the Two Micron All-Sky Survey. Features characteristic of both L and T dwarfs...
S Ori 70: Just a Foreground Field Brown Dwarf? (2003)
Burgasser, Adam J., Kirkpatrick, J. Davy, McGovern, Mark R., McLean, Ian S., Prato, L., Reid, I. Neill
We examine recent claims that the T-type brown dwarf S Ori 053810.1-023626 (S Ori 70) is a spectroscopically verified low mass (3$^{+5}_{-1}$ M$_{Jup}$) member of the 1--8 Myr $\sigma$ Orionis...
Identifying Young Brown Dwarfs Using Gravity-Sensitive Spectral Features (2003)
McGovern, Mark R., Kirkpatrick, J. Davy, McLean, Ian S., Burgasser, Adam J., Prato, L., Lowrance, Patrick J.
We report the initial results of the Brown Dwarf Spectroscopic Survey Gravity Project, to study gravity sensitive features as indicators of youth in brown dwarfs. Low-resolution (R~2000) J-band and...
The NIRSPEC Brown Dwarf Spectroscopic Survey. I. Low-Resolution Near-Infrared Spectra (2003)
McLean, Ian S., McGovern, Mark R., Burgasser, Adam J., Kirkpatrick, J. Davy, Prato, L., Kim, Sungsoo S.
We present the first results of a near-infrared (0.96-2.31 micron) spectroscopic survey of M, L, and T dwarfs obtained with NIRSPEC on the Keck II telescope. Our new survey has a resolving power of R...
Burgasser, Adam J., McElwain, Michael W., Kirkpatrick, J. Davy
We present the discovery of three new Southern Hemisphere T dwarfs identified in the Two Micron All Sky Survey. These objects, 2MASS 0348-6022, 2MASS 0516-0445, and 2MASS 2228-4310, have...
The Spectra of T Dwarfs. II. Red Optical Data (2003)
Burgasser, Adam J., Kirkpatrick, J. Davy, Liebert, James, Burrows, Adam
We present 6300--10100 {\AA} spectra for a sample of 13 T dwarfs observed using LRIS mounted on the Keck I 10m Telescope. A variety of features are identified and analyzed, including...
Photometric Variability at the L/T Dwarf Boundary (2003)
Enoch, Melissa L., Brown, Michael E., Burgasser, Adam J.
We have monitored the photometric variability of nine field L and T brown dwarfs for 10 nights during the course of one month with the Palomar 60 inch Telescope Near-Infrared Camera. Results of...
Infrared Parallaxes for Methane T dwarfs (2003)
Tinney, C. G., Burgasser, Adam J., Kirkpatrick, J. Davy.
We report final results from our 2.5 year infrared parallax program carried out with the European Southern Observatory 3.5m New Technology Telescope and the SOFI infrared camera. Our program targeted...
The First Substellar Subdwarf? Discovery of a Metal-poor L Dwarf with Halo Kinematics (2003)
Burgasser, Adam J., Kirkpatrick, J. Davy, Burrows, Adam, Liebert, James, Reid, I. Neill, Gizis, John E., ...
We present the discovery of the first L-type subdwarf, 2MASS J05325346+8246465. This object exhibits enhanced collision-induced H$_2$ absorption, resulting in blue NIR colors ($J-K_s =...
Binarity in Brown Dwarfs: T Dwarf Binaries Discovered with the Hubble Space Telescope WPFC2 (2002)
Burgasser, Adam J., Kirkpatrick, J. Davy, Reid, I. Neill, Brown, Michael E., Miskey, Cherie L., Gizis, John E.
(abridged) We present the discovery of two T dwarf binaries, 2MASS 1225-2739AB and 2MASS 1534-2952AB, identified in a sample of ten T dwarfs imaged with the Hubble Space Telescope Wide Field...
The 2MASS Wide-Field T Dwarf Search. I. Discovery of a Bright T Dwarf Within 10 pc of the Sun (2002)
Burgasser, Adam J., Kirkpatrick, J. Davy, McElwain, Michael W., Cutri, Roc M., Burgasser, Albert J., Skrutskie, Michael F.
We present the discovery of a bright (J = 13.94$\pm$0.03) T dwarf, 2MASS 1503+2525, identified in a new, wide-field search for T dwarfs using the recently completed Two Micron All Sky Survey (2MASS)....
Evidence for Cloud Disruption in the L/T Dwarf Transition (2002)
Burgasser, Adam J., Marley, Mark S., Ackerman, Andrew S., Saumon, Didier, Lodders, Katharina, Dahn, Conard C., ...
Clouds of metal-bearing condensates play a critical role in shaping the emergent spectral energy distributions of the coolest classes of low-mass stars and brown dwarfs, L and T dwarfs. Because...
A Search for Variability in the Active T dwarf 2MASS 1237+6526 (2002)
Burgasser, Adam J., Liebert, James, Kirkpatrick, J. Davy, Gizis, John E.
We present spectroscopic and imaging observations of the active T dwarf 2MASS 1237+6526, intended to investigate the emission mechanism of this cool brown dwarf. The H$\alpha$ emission line first...
The Spectra and Classification of L and T Dwarfs (2001)
In this contribution, I discuss some of the salient features of L and T dwarf spectra in both the red optical (6300--10000 {\AA}) and near-infrared (1--2.5 $\micron$) wavelength regimes. Important...
Theoretical Spectral Models of T Dwarfs at Short Wavelengths and Their Comparison with Data (2001)
Burrows, Adam, Burgasser, Adam J., Kirkpatrick, J. Davy, Liebert, James, Milsom, J. A., Sudarsky, David, ...
We have generated new, self-consistent spectral and atmosphere models for the effective temperature range 600 K to 1300 K thought to encompass the known T dwarfs. For the first time, theoretical...
The Spectra of T Dwarfs I: Near-Infrared Data and Spectral Classification (2001)
Burgasser, Adam J., Kirkpatrick, J. Davy, Brown, Michael E., Reid, I. Neill, Burrows, Adam, Liebert, James, ...
We present near-infrared spectra for a sample of T dwarfs, including eleven new discoveries made using the Two Micron All Sky Survey. These objects are distinguished from warmer (L-type) brown dwarfs...
Brown Dwarf Companions to G-type Stars. I: Gliese 417B and Gliese 584C (2001)
Kirkpatrick, J. Davy, Dahn, Conard C., Monet, David G., Reid, I. Neill, Gizis, John E., Liebert, James, ...
We present astrometric and spectroscopic observations confirming that two nearby G dwarf systems (Gliese 417 = BD+36 2162 and Gliese 584AB = eta CrB AB) have a widely separated, L dwarf, substellar...
The Classification of T Dwarfs (2001)
Burgasser, Adam J., Kirkpatrick, J. Davy, Brown, Michael E.
We discuss methods for classifying T dwarfs based on spectral morphological features and indices. T dwarfs are brown dwarfs which exhibit methane absorption bands at 1.6 and 2.2 ${\mu}m$. Spectra at...
Optical Spectroscopy of T Dwarfs (2001)
Burgasser, Adam J., Kirkpatrick, J. Davy
Optical spectra are presented for a sample of T dwarfs, obtained using the Keck 10m Low Resolution Imaging Spectrograph. Dominant features are discussed, including possible temperature diagnostics.
Discovery of a Bright Field Methane (T-type) Brown Dwarf by 2MASS (2000)
Burgasser, Adam J., Wilson, John C., Kirkpatrick, J. Davy, Skrutskie, Michael F., Colonno, Michael R., Enos, Alan T., ...
We report the discovery of a bright (J = 13.83$\pm$0.03) methane brown dwarf, or T dwarf, by the Two Micron All Sky Survey. This object, 2MASSI J0559191-140448, is the first brown dwarf identified by...
Sixty-seven Additional L Dwarfs Discovered by the Two Micron All Sky Survey (2MASS) (2000)
Kirkpatrick, J. Davy, Reid, I. Neill, Liebert, James, Gizis, John E., Burgasser, Adam J., Monet, David G., ...
We present JHKs photometry, far red spectra, and spectral classifications for an additional 67 L dwarfs discovered by the Two Micron All Sky Survey. One of the goals of this new search was to locate...
Detection of H Alpha Emission in a Methane (T-Type) Brown Dwarf (2000)
Burgasser, Adam J., Kirkpatrick, J. Davy, Reid, I. Neill, Liebert, James, Gizis, John E., Brown, Michael E.
We report the detection of H{$\alpha$} emission in the T dwarf (methane brown dwarf) 2MASSW J1237392+652615 over three days using the Keck Low Resolution Imaging Spectrograph. The measured line flux,...
An Improved Red Spectrum of the Methane or T-dwarf SDSS 1624+0029: Role of the Alkali Metals (2000)
Liebert, James, Reid, I. Neill, Burrows, Adam, Burgasser, Adam J., Kirkpatrick, J. Davy, Gizis, John E.
A Keck~II low resolution spectrum shortward of ome-micron is presented for SDSS 1624+0029, the first field methane or T dwarf discovered in the Sloan Digital Sky Survey. Significant flux is detected...
Adam J. Burgasser, J. Davy Kirkpatrick, Michael E. Brown, I. Neill Reid, John E. Gizis, Conard C. Dahn, ...
We report the discovery of four field methane (“T”-type) brown dwarfs using Two Micron All-Sky Survey (2MASS) data. One additional methane dwarf, previously discovered by the Sloan Digital Sky...