OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4
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 source, as indicated by prominent metal-hydride bands, alkali lines, and collision-induced H2 absorp...
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| Formaat: | Artikel |
| Taal: | en_US |
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Institute of Physics
2010
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| Online toegang: | http://hdl.handle.net/1721.1/52544 https://orcid.org/0000-0003-3939-3297 |
| _version_ | 1826190513264394240 |
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| author | Burgasser, Adam J. Witte, Soeren Helling, Chirstiane Sanderson, Robyn Ellyn Bochanski, John J. Hauschildt, Peter H. |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Burgasser, Adam J. Witte, Soeren Helling, Chirstiane Sanderson, Robyn Ellyn Bochanski, John J. Hauschildt, Peter H. |
| author_sort | Burgasser, Adam J. |
| collection | MIT |
| description | 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 source, as indicated by prominent metal-hydride bands, alkali lines, and collision-induced H2 absorption. The optical and near-infrared spectra of SDSS J1256-0224 are similar to those of the sdL4 2MASS J16262034+3925190, and we derive a classification of sdL3.5 based on the preliminary scheme of Burgasser, Cruz, and Kirkpatrick. The kinematics of SDSS J1256-0224 are consistent with membership in the Galactic inner halo, with estimated UVW space velocities indicating a slightly prograde, eccentric, and inclined Galactic orbit (3.5 lsim R lsim 11 kpc; |Zmax| = 7.5 kpc). Comparison to synthetic spectra computed with the PHOENIX code, including the recent implementation of kinetic condensate formation (DRIFT-PHOENIX), indicates T eff ≈ 2100-2500 K and [M/H] ≈ –1.5 to –1.0 for log g ≈ 5.0-5.5 (cgs), although there are clear discrepancies between model and observed spectra particularly in the red optical region. As such, any conclusions on the role of metallicity in condensate grain and cloud formation are probably premature. Indeed, a shift in the temperature scale of L subdwarfs relative to L dwarfs may obviate the need for modified condensate and grain chemistry in low metallicity atmospheres. |
| first_indexed | 2024-09-23T08:41:07Z |
| format | Article |
| id | mit-1721.1/52544 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:41:07Z |
| publishDate | 2010 |
| publisher | Institute of Physics |
| record_format | dspace |
| spelling | mit-1721.1/525442022-09-23T13:51:06Z OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4 Burgasser, Adam J. Witte, Soeren Helling, Chirstiane Sanderson, Robyn Ellyn Bochanski, John J. Hauschildt, Peter H. Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Burgasser, Adam J. Burgasser, Adam J. Sanderson, Robyn Ellyn Bochanski, John J. 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 source, as indicated by prominent metal-hydride bands, alkali lines, and collision-induced H2 absorption. The optical and near-infrared spectra of SDSS J1256-0224 are similar to those of the sdL4 2MASS J16262034+3925190, and we derive a classification of sdL3.5 based on the preliminary scheme of Burgasser, Cruz, and Kirkpatrick. The kinematics of SDSS J1256-0224 are consistent with membership in the Galactic inner halo, with estimated UVW space velocities indicating a slightly prograde, eccentric, and inclined Galactic orbit (3.5 lsim R lsim 11 kpc; |Zmax| = 7.5 kpc). Comparison to synthetic spectra computed with the PHOENIX code, including the recent implementation of kinetic condensate formation (DRIFT-PHOENIX), indicates T eff ≈ 2100-2500 K and [M/H] ≈ –1.5 to –1.0 for log g ≈ 5.0-5.5 (cgs), although there are clear discrepancies between model and observed spectra particularly in the red optical region. As such, any conclusions on the role of metallicity in condensate grain and cloud formation are probably premature. Indeed, a shift in the temperature scale of L subdwarfs relative to L dwarfs may obviate the need for modified condensate and grain chemistry in low metallicity atmospheres. 2010-03-12T17:32:08Z 2010-03-12T17:32:08Z 2009-04 2008-10 Article http://purl.org/eprint/type/SubmittedJournalArticle 0004-637X http://hdl.handle.net/1721.1/52544 Adam J. Burgasser et al. “OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4.” The Astrophysical Journal 697.1 (2009): 148. https://orcid.org/0000-0003-3939-3297 en_US http://dx.doi.org/10.1088/0004-637x/697/1/148 Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Institute of Physics author/dept web page |
| spellingShingle | Burgasser, Adam J. Witte, Soeren Helling, Chirstiane Sanderson, Robyn Ellyn Bochanski, John J. Hauschildt, Peter H. OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4 |
| title | OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4 |
| title_full | OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4 |
| title_fullStr | OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4 |
| title_full_unstemmed | OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4 |
| title_short | OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF THE L SUBDWARF SDSS J125637.13-022452.4 |
| title_sort | optical and near infrared spectroscopy of the l subdwarf sdss j125637 13 022452 4 |
| url | http://hdl.handle.net/1721.1/52544 https://orcid.org/0000-0003-3939-3297 |
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