2MASS J06164006-6407194: The First Outer Halo L Subdwarf

Michael C. Cushing; Dagny Looper; Adam J. Burgasser; J. Davy Kirkpatrick; Jacqueline Faherty; Kelle L. Cruz; Anne Sweet; Robyn E. Sanderson

2MASS J06164006-6407194: The First Outer Halo L Subdwarf

Michael C. Cushing, Dagny Looper, Adam J. Burgasser, J. Davy Kirkpatrick, Jacqueline Faherty, Kelle L. Cruz, Anne Sweet, Robyn E. Sanderson

Astronomy

Research output: Contribution to journal › Article › Academic › peer-review

35 Citations (Scopus)

Abstract

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 of both a cool and metal poor atmosphere including a heavily pressure-broadened K I resonant doublet, Cs I and Rb I lines, molecular bands of CaH, TiO, CrH, FeH, and H2O, and enhanced collision induced absorption of H2. We assign 2MASS J0616-6407 a spectral type of sdL5 based on a comparison of its red optical spectrum to that of near solar-metallicity L dwarfs. Its high proper motion (μ = 1farcs405 ± 0.008 yr-1), large radial velocity (V rad = 454 ± 15 km s-1), estimated u, v, w velocities (94, -573, 125) km s-1 and Galactic orbit with an apogalacticon at ~29 kpc are indicative of membership in the outer halo making 2MASS J0616-6407 the first ultracool member of this population.

Original language	English
Pages (from-to)	986-993
Journal	The Astrophysical Journal
Volume	696
Issue number	1
Publication status	Published - 1-May-2009

Keywords

infrared: stars
stars: individual: 2MASS J0164006-6407194
stars: low-mass
brown dwarfs
subdwarfs

Access to Document

http://adsabs.harvard.edu/abs/2009ApJ...696..986C

Cite this

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title = "2MASS J06164006-6407194: The First Outer Halo L Subdwarf",

abstract = "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 of both a cool and metal poor atmosphere including a heavily pressure-broadened K I resonant doublet, Cs I and Rb I lines, molecular bands of CaH, TiO, CrH, FeH, and H2O, and enhanced collision induced absorption of H2. We assign 2MASS J0616-6407 a spectral type of sdL5 based on a comparison of its red optical spectrum to that of near solar-metallicity L dwarfs. Its high proper motion (μ = 1farcs405 ± 0.008 yr-1), large radial velocity (V rad = 454 ± 15 km s-1), estimated u, v, w velocities (94, -573, 125) km s-1 and Galactic orbit with an apogalacticon at ~29 kpc are indicative of membership in the outer halo making 2MASS J0616-6407 the first ultracool member of this population.",

keywords = "infrared: stars, stars: individual: 2MASS J0164006-6407194, stars: low-mass, brown dwarfs, subdwarfs",

author = "Cushing, {Michael C.} and Dagny Looper and Burgasser, {Adam J.} and Kirkpatrick, {J. Davy} and Jacqueline Faherty and Cruz, {Kelle L.} and Anne Sweet and Sanderson, {Robyn E.}",

year = "2009",

month = may,

day = "1",

language = "English",

volume = "696",

pages = "986--993",

journal = "The Astrophysical Journal",

issn = "0004-637X",

publisher = "IOP PUBLISHING LTD",

number = "1",

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TY - JOUR

T1 - 2MASS J06164006-6407194: The First Outer Halo L Subdwarf

AU - Cushing, Michael C.

AU - Looper, Dagny

AU - Burgasser, Adam J.

AU - Kirkpatrick, J. Davy

AU - Faherty, Jacqueline

AU - Cruz, Kelle L.

AU - Sweet, Anne

AU - Sanderson, Robyn E.

PY - 2009/5/1

Y1 - 2009/5/1

N2 - 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 of both a cool and metal poor atmosphere including a heavily pressure-broadened K I resonant doublet, Cs I and Rb I lines, molecular bands of CaH, TiO, CrH, FeH, and H2O, and enhanced collision induced absorption of H2. We assign 2MASS J0616-6407 a spectral type of sdL5 based on a comparison of its red optical spectrum to that of near solar-metallicity L dwarfs. Its high proper motion (μ = 1farcs405 ± 0.008 yr-1), large radial velocity (V rad = 454 ± 15 km s-1), estimated u, v, w velocities (94, -573, 125) km s-1 and Galactic orbit with an apogalacticon at ~29 kpc are indicative of membership in the outer halo making 2MASS J0616-6407 the first ultracool member of this population.

AB - 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 of both a cool and metal poor atmosphere including a heavily pressure-broadened K I resonant doublet, Cs I and Rb I lines, molecular bands of CaH, TiO, CrH, FeH, and H2O, and enhanced collision induced absorption of H2. We assign 2MASS J0616-6407 a spectral type of sdL5 based on a comparison of its red optical spectrum to that of near solar-metallicity L dwarfs. Its high proper motion (μ = 1farcs405 ± 0.008 yr-1), large radial velocity (V rad = 454 ± 15 km s-1), estimated u, v, w velocities (94, -573, 125) km s-1 and Galactic orbit with an apogalacticon at ~29 kpc are indicative of membership in the outer halo making 2MASS J0616-6407 the first ultracool member of this population.

KW - infrared: stars

KW - stars: individual: 2MASS J0164006-6407194

KW - stars: low-mass

KW - brown dwarfs

KW - subdwarfs

M3 - Article

VL - 696

SP - 986

EP - 993

JO - The Astrophysical Journal

JF - The Astrophysical Journal

SN - 0004-637X

IS - 1

ER -