High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38
We report on high dispersion spectroscopy of the Ha absorption line of the cool DA white dwarf G 29 -38. This is the star for which a recently detected infrared excess has been suggested to be due to a possible brown dwarf companion by Zuckerman and Becklin (1986, 1987). Three echelle spectra obt...
Main Authors: | , , |
---|---|
Other Authors: | |
Language: | en_US |
Published: |
Steward Observatory, The University of Arizona (Tucson, Arizona)
1988
|
Subjects: | |
Online Access: | http://hdl.handle.net/10150/623899 http://arizona.openrepository.com/arizona/handle/10150/623899 |
id |
ndltd-arizona.edu-oai-arizona.openrepository.com-10150-623899 |
---|---|
record_format |
oai_dc |
spelling |
ndltd-arizona.edu-oai-arizona.openrepository.com-10150-6238992017-06-08T03:00:32Z High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38 Liebert, J. Saffer, R. A. Pilachowski, C. A. Univ Arizona, Steward Observ Absorption spectra Brown dwarf stars H alpha emission line stars Infrared radiation White dwarf stars We report on high dispersion spectroscopy of the Ha absorption line of the cool DA white dwarf G 29 -38. This is the star for which a recently detected infrared excess has been suggested to be due to a possible brown dwarf companion by Zuckerman and Becklin (1986, 1987). Three echelle spectra obtained at the Multiple Mirror Telescope and at the Kitt Peak Mayall 4m telescope in 1987 December show no evidence for radial velocity variations larger than -'1.1 ± 8.7 km s -1 and are used to derive a weighted heliocentric radial velocity Vr = 33.7 ± 4.3 km s -1 for the white dwarf. No emission component from the hypothesized secondary star is detected. These negative results do not constitute strong evidence against the companion hypothesis, since the expected orbital velocity of the white dwarf component could be quite small, and the companion's line emission could be too faint to be detected. However, the observation of a sharp absorption line core restricts the possible rotation of the white dwarf to < 40 km s -1 and ensures that any surface magnetic field has a strength < 105 gauss. These results make it unlikely that the DA white dwarf has previously been in a cataclysmic variable accretion phase. 1988-10 text Article AJ 97: 182-185 (Jan. 1989) http://hdl.handle.net/10150/623899 http://arizona.openrepository.com/arizona/handle/10150/623899 en_US Preprints of the Steward Observatory #839 http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1989AJ.....97..182L&db_key=AST&data_type=HTML&format=&high=3ed65e9cd000634 Copyright © All Rights Reserved. Steward Observatory, The University of Arizona (Tucson, Arizona) Steward Observatory Parker Library SO QB 4 .S752 ARCH |
collection |
NDLTD |
language |
en_US |
sources |
NDLTD |
topic |
Absorption spectra Brown dwarf stars H alpha emission line stars Infrared radiation White dwarf stars |
spellingShingle |
Absorption spectra Brown dwarf stars H alpha emission line stars Infrared radiation White dwarf stars Liebert, J. Saffer, R. A. Pilachowski, C. A. High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38 |
description |
We report on high dispersion spectroscopy of the Ha absorption line of
the cool DA white dwarf G 29 -38. This is the star for which a recently detected
infrared excess has been suggested to be due to a possible brown dwarf companion by
Zuckerman and Becklin (1986, 1987). Three echelle spectra obtained at the Multiple
Mirror Telescope and at the Kitt Peak Mayall 4m telescope in 1987 December show
no evidence for radial velocity variations larger than -'1.1 ± 8.7 km s -1 and are used
to derive a weighted heliocentric radial velocity Vr = 33.7 ± 4.3 km s -1 for the white
dwarf. No emission component from the hypothesized secondary star is detected.
These negative results do not constitute strong evidence against the companion
hypothesis, since the expected orbital velocity of the white dwarf component could
be quite small, and the companion's line emission could be too faint to be detected.
However, the observation of a sharp absorption line core restricts the possible rotation
of the white dwarf to < 40 km s -1 and ensures that any surface magnetic field has
a strength < 105 gauss. These results make it unlikely that the DA white dwarf
has previously been in a cataclysmic variable accretion phase. |
author2 |
Univ Arizona, Steward Observ |
author_facet |
Univ Arizona, Steward Observ Liebert, J. Saffer, R. A. Pilachowski, C. A. |
author |
Liebert, J. Saffer, R. A. Pilachowski, C. A. |
author_sort |
Liebert, J. |
title |
High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38 |
title_short |
High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38 |
title_full |
High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38 |
title_fullStr |
High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38 |
title_full_unstemmed |
High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38 |
title_sort |
high dispersion observations of h alpha in the suspected brown dwarf, white dwarf binary system g29-38 |
publisher |
Steward Observatory, The University of Arizona (Tucson, Arizona) |
publishDate |
1988 |
url |
http://hdl.handle.net/10150/623899 http://arizona.openrepository.com/arizona/handle/10150/623899 |
work_keys_str_mv |
AT liebertj highdispersionobservationsofhalphainthesuspectedbrowndwarfwhitedwarfbinarysystemg2938 AT safferra highdispersionobservationsofhalphainthesuspectedbrowndwarfwhitedwarfbinarysystemg2938 AT pilachowskica highdispersionobservationsofhalphainthesuspectedbrowndwarfwhitedwarfbinarysystemg2938 |
_version_ |
1718456670643814400 |