Additional ultracool white dwarfs found in the sloan digital sky survey

Hugh C. Harris; Evalyn Gates; Geza Gyuk; Mark Subbarao; Scott F. Anderson; Patrick B. Hall; Jeffrey A. Munn; James Liebert; Gillian R. Knapp; D. Bizyaev; E. Malanushenko; V. Malanushenko; K. Pan; Donald P. Schneider; J. Allyn Smith

doi:10.1086/587160

Additional ultracool white dwarfs found in the sloan digital sky survey

Hugh C. Harris, Evalyn Gates, Geza Gyuk, Mark Subbarao, Scott F. Anderson, Patrick B. Hall, Jeffrey A. Munn, James Liebert, Gillian R. Knapp, D. Bizyaev, E. Malanushenko, V. Malanushenko, K. Pan, Donald P. Schneider, J. Allyn Smith

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32 Scopus citations

Abstract

We identify seven new ultracool white dwarfs discovered in the Sloan Digital Sky Survey (SDSS). The SDSS photometry, spectra, and proper motions are presented, and additional BVRI data are given for these and other previously discovered ultracool white dwarfs. The observed colors span a remarkably wide range, qualitatively similar to colors predicted by models for very cool white dwarfs. One of the new stars (SDSS J1251+44) exhibits strong collision-induced absorption (CIA) in its spectra, while the spectra and colors of the other six are consistent with mild CIA. Another of the new discoveries (SDSS J2239+00A) is part of a binary system - its companion is also a cool white dwarf, and other data indicate that the companion exhibits an infrared flux deficiency, making this the first binary system composed of two CIA white dwarfs. A third discovery (SDSS J0310-00) has weak Balmer emission lines. The proper motions of all seven stars are consistent with membership in the disk or thick disk.

Original language	English (US)
Pages (from-to)	697-703
Number of pages	7
Journal	Astrophysical Journal
Volume	679
Issue number	1
DOIs	https://doi.org/10.1086/587160
State	Published - May 20 2008

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/587160

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@article{a3fa6b5000c9413eb75cbba125d0ffaf,

title = "Additional ultracool white dwarfs found in the sloan digital sky survey",

abstract = "We identify seven new ultracool white dwarfs discovered in the Sloan Digital Sky Survey (SDSS). The SDSS photometry, spectra, and proper motions are presented, and additional BVRI data are given for these and other previously discovered ultracool white dwarfs. The observed colors span a remarkably wide range, qualitatively similar to colors predicted by models for very cool white dwarfs. One of the new stars (SDSS J1251+44) exhibits strong collision-induced absorption (CIA) in its spectra, while the spectra and colors of the other six are consistent with mild CIA. Another of the new discoveries (SDSS J2239+00A) is part of a binary system - its companion is also a cool white dwarf, and other data indicate that the companion exhibits an infrared flux deficiency, making this the first binary system composed of two CIA white dwarfs. A third discovery (SDSS J0310-00) has weak Balmer emission lines. The proper motions of all seven stars are consistent with membership in the disk or thick disk.",

author = "Harris, {Hugh C.} and Evalyn Gates and Geza Gyuk and Mark Subbarao and Anderson, {Scott F.} and Hall, {Patrick B.} and Munn, {Jeffrey A.} and James Liebert and Knapp, {Gillian R.} and D. Bizyaev and E. Malanushenko and V. Malanushenko and K. Pan and Schneider, {Donald P.} and Smith, {J. Allyn}",

note = "Funding Information: This research was supported by CONICET and CIUNT grants to S. S. S{\'a}nchez. We wish to thank Dr H. J. F. Maccioni and Dr J. L. Daniotti (CIQUIBIC, CONICET-Univ. Nacional de C{\'o}rdoba, Argentina) for helpful discussions. Thanks are also extended to Mr E. Dozetos for his photographic assistance, and to Mrs Virginia M{\'e}ndez for her proof-reading.",

year = "2008",

month = may,

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doi = "10.1086/587160",

language = "English (US)",

volume = "679",

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journal = "Astrophysical Journal",

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T1 - Additional ultracool white dwarfs found in the sloan digital sky survey

AU - Harris, Hugh C.

AU - Gates, Evalyn

AU - Gyuk, Geza

AU - Subbarao, Mark

AU - Anderson, Scott F.

AU - Hall, Patrick B.

AU - Munn, Jeffrey A.

AU - Liebert, James

AU - Knapp, Gillian R.

AU - Bizyaev, D.

AU - Malanushenko, E.

AU - Malanushenko, V.

AU - Pan, K.

AU - Schneider, Donald P.

AU - Smith, J. Allyn

N1 - Funding Information: This research was supported by CONICET and CIUNT grants to S. S. Sánchez. We wish to thank Dr H. J. F. Maccioni and Dr J. L. Daniotti (CIQUIBIC, CONICET-Univ. Nacional de Córdoba, Argentina) for helpful discussions. Thanks are also extended to Mr E. Dozetos for his photographic assistance, and to Mrs Virginia Méndez for her proof-reading.

PY - 2008/5/20

Y1 - 2008/5/20

N2 - We identify seven new ultracool white dwarfs discovered in the Sloan Digital Sky Survey (SDSS). The SDSS photometry, spectra, and proper motions are presented, and additional BVRI data are given for these and other previously discovered ultracool white dwarfs. The observed colors span a remarkably wide range, qualitatively similar to colors predicted by models for very cool white dwarfs. One of the new stars (SDSS J1251+44) exhibits strong collision-induced absorption (CIA) in its spectra, while the spectra and colors of the other six are consistent with mild CIA. Another of the new discoveries (SDSS J2239+00A) is part of a binary system - its companion is also a cool white dwarf, and other data indicate that the companion exhibits an infrared flux deficiency, making this the first binary system composed of two CIA white dwarfs. A third discovery (SDSS J0310-00) has weak Balmer emission lines. The proper motions of all seven stars are consistent with membership in the disk or thick disk.

AB - We identify seven new ultracool white dwarfs discovered in the Sloan Digital Sky Survey (SDSS). The SDSS photometry, spectra, and proper motions are presented, and additional BVRI data are given for these and other previously discovered ultracool white dwarfs. The observed colors span a remarkably wide range, qualitatively similar to colors predicted by models for very cool white dwarfs. One of the new stars (SDSS J1251+44) exhibits strong collision-induced absorption (CIA) in its spectra, while the spectra and colors of the other six are consistent with mild CIA. Another of the new discoveries (SDSS J2239+00A) is part of a binary system - its companion is also a cool white dwarf, and other data indicate that the companion exhibits an infrared flux deficiency, making this the first binary system composed of two CIA white dwarfs. A third discovery (SDSS J0310-00) has weak Balmer emission lines. The proper motions of all seven stars are consistent with membership in the disk or thick disk.

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Additional ultracool white dwarfs found in the sloan digital sky survey

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