Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis

We present 0.6-2.5 mum, Rgreater than or similar to400 spectra of 27 cool, low-luminosity stars and substellar objects. Based on these and previously published spectra, we develop a preliminary spectral classification system for L and T dwarfs. For late L and T types the classification system is bas...

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Szerző:	Geballe, T R
Közreműködő(k):	Knapp, G R Leggett, S K Fan, X Golimowski, D A Anderson, S Brinkmann, J Csabai, I Gunn, J E Hawley, S L Hennessy, G Henry, T J Hill, G J Hindsley, R B Ivezic, Z Lupton, R H Mcdaniel, A Munn, J A Narayanan, V K Peng, E Pier, J R Rockosi, C M Schneider, D P Smith, J A Strauss, M A Tsvetanov, Z I Uomoto, A York, D G Zheng, W
Formátum:	folyóiratcikk
Megjelenés:	2002
Online elérés:	http://hdl.handle.net/10831/49193
Címkék:	Új címke A tételhez itt fűzhet saját címkét!

id	edit-10831-49193
recordtype	dspace
spelling	edit-10831-491932020-08-08T20:03:40Z Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis Geballe, T R Knapp, G R Leggett, S K Fan, X Golimowski, D A Anderson, S Brinkmann, J Csabai, I Gunn, J E Hawley, S L Hennessy, G Henry, T J Hill, G J Hindsley, R B Ivezic, Z Lupton, R H Mcdaniel, A Munn, J A Narayanan, V K Peng, E Pier, J R Rockosi, C M Schneider, D P Smith, J A Strauss, M A Tsvetanov, Z I Uomoto, A York, D G Zheng, W We present 0.6-2.5 mum, Rgreater than or similar to400 spectra of 27 cool, low-luminosity stars and substellar objects. Based on these and previously published spectra, we develop a preliminary spectral classification system for L and T dwarfs. For late L and T types the classification system is based entirely on four spectral indices in the 1-2.5 mum interval. Two of these indices are derived from water absorption bands at 1.15 and 1.4 km, the latter of which shows a smooth increase in depth through the L and T sequences and can be used to classify both spectral types. The other two indices make use of methane absorption features in the H and K bands, with the K-band index also applicable to mid-to-late L dwarfs. Continuum indices shortward of 1 mum used by previous authors to classify L dwarfs are found to be useful only through mid-L subclasses. We employ the 1.5 mum water index and the 2.2 mum methane index to complete the L classification through L9.5 and to link the new system with a modified version of the 2MASS "color-d" index. By correlating the depths of the methane and water absorption features, we establish a T spectral sequence from T0 to T8, based on all four indices, that is a smooth continuation of the L sequence. We reclassify two 2MASS L8 dwarfs as L9 and L9.5 and identify one SDSS object as L9. In the proposed system methane absorption appears in the K band approximately at L8, two subclasses earlier than its appearance in the H band. The L and T spectral classes are distinguished by the absence and presence, respectively, of H-band methane absorption. 2002 info:eu-repo/semantics/article http://hdl.handle.net/10831/49193 doi:10.1086/324078 elte:000173154300044 elte:17944398803 elte:1064386 elte:1 elte:ASTROPHYS J elte:ASTROPHYSICAL JOURNAL elte:564 elte:10067248 info:eu-repo/semantics/openAccess application/pdf LOMS: https://edit.elte.hu/xmlui/bitstream/10831/49193/1/Towards%20Spectral%20Classification%20of%20L%20and%20T%20Dwarfs.pdf
institution	L_EDIT
description	We present 0.6-2.5 mum, Rgreater than or similar to400 spectra of 27 cool, low-luminosity stars and substellar objects. Based on these and previously published spectra, we develop a preliminary spectral classification system for L and T dwarfs. For late L and T types the classification system is based entirely on four spectral indices in the 1-2.5 mum interval. Two of these indices are derived from water absorption bands at 1.15 and 1.4 km, the latter of which shows a smooth increase in depth through the L and T sequences and can be used to classify both spectral types. The other two indices make use of methane absorption features in the H and K bands, with the K-band index also applicable to mid-to-late L dwarfs. Continuum indices shortward of 1 mum used by previous authors to classify L dwarfs are found to be useful only through mid-L subclasses. We employ the 1.5 mum water index and the 2.2 mum methane index to complete the L classification through L9.5 and to link the new system with a modified version of the 2MASS "color-d" index. By correlating the depths of the methane and water absorption features, we establish a T spectral sequence from T0 to T8, based on all four indices, that is a smooth continuation of the L sequence. We reclassify two 2MASS L8 dwarfs as L9 and L9.5 and identify one SDSS object as L9. In the proposed system methane absorption appears in the K band approximately at L8, two subclasses earlier than its appearance in the H band. The L and T spectral classes are distinguished by the absence and presence, respectively, of H-band methane absorption.
format	Journal Article
physical	application/pdf
author	Geballe, T R
spellingShingle	Geballe, T R Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis
author_facet	Geballe, T R Knapp, G R Leggett, S K Fan, X Golimowski, D A Anderson, S Brinkmann, J Csabai, I Gunn, J E Hawley, S L Hennessy, G Henry, T J Hill, G J Hindsley, R B Ivezic, Z Lupton, R H Mcdaniel, A Munn, J A Narayanan, V K Peng, E Pier, J R Rockosi, C M Schneider, D P Smith, J A Strauss, M A Tsvetanov, Z I Uomoto, A York, D G Zheng, W
author2	Knapp, G R Leggett, S K Fan, X Golimowski, D A Anderson, S Brinkmann, J Csabai, I Gunn, J E Hawley, S L Hennessy, G Henry, T J Hill, G J Hindsley, R B Ivezic, Z Lupton, R H Mcdaniel, A Munn, J A Narayanan, V K Peng, E Pier, J R Rockosi, C M Schneider, D P Smith, J A Strauss, M A Tsvetanov, Z I Uomoto, A York, D G Zheng, W
title	Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis
title_short	Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis
title_full	Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis
title_fullStr	Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis
title_full_unstemmed	Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis
title_sort	toward spectral classification of l and t dwarfs: infrared and optical spectroscopy and analysis
publishDate	2002
publishDateSort	2002
url	http://hdl.handle.net/10831/49193
first_indexed	2020-08-08T20:03:40Z
last_indexed	2023-09-01T12:17:01Z
_version_	1775829957962891264
score	13,369315

Toward spectral classification of L and T dwarfs: Infrared and optical spectroscopy and analysis

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