J/A+A/446/515 Distances of nearby ultracool dwarfs (Phan-Bao+, 2006)
Spectroscopic distances of nearby ultracool dwarfs.
Phan-Bao N., Bessell M.S.
<Astron. Astrophys., 446, 515-523 (2006)>
=2006A&A...446..515P 2006A&A...446..515P
ADC_Keywords: Stars, nearby ; Stars, M-type ; Photometry, infrared ;
Stars, distances
Keywords: stars: very low mass, brown dwarfs
Abstract:
We present updated results of spectroscopic follow-up observations of
a sample of 45 M dwarf candidates identified by Phan-Bao et al. (2003,
Cat. J/A+A/401/959) based on the DENIS photometry and proper motion
measurements. Forty one of these are nearby late-M dwarfs (d<30pc)
with spectral types ranging from M5.0 to M8.5 computed from the
spectral indices. One contaminant is probably an F-G main sequence
star reddened by intervening dust and three stars that were not
observed have previous classifications as M dwarfs in the literature.
In this paper, we identify three M7.5, five M8.0, one M8.5 dwarf and
confirm two new M8.0 dwarf members of the 25pc volume.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 108 42 Spectral indices
table2.dat 118 42 Spectroscopic distances and spectral types
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See also:
B/denis : The DENIS database (Epchtein+, 1999)
I/98 : NLTT Catalogue (Luyten, 1979)
I/87 : LHS Catalogue, 2nd Edition (Luyten 1979)
J/A+A/380/590 : 30 DENIS late-M dwarfs between 15 and 30pc (Phan-Bao+, 2001)
J/A+A/401/959 : 35 DENIS late-M dwarfs between 10 + 30pc (Phan-Bao+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name The DENIS name (except VB 10)
18- 26 A9 --- OName The NLTT/LHS name
30- 33 F4.2 --- Halpha The Halpha index (1)
34 A1 --- u_Halpha [:] Unreliable value
37- 40 F4.2 --- PC3 The PC3 spectral index (2)
44- 47 F4.2 --- CrH1 The CrH1 spectral index (2)
51- 54 F4.2 --- CrH2 The CrH2 spectral index (2)
58- 61 F4.2 --- FeH1 The FeH1 spectral index (2)
65- 68 F4.2 --- FeH2 The FeH2 spectral index (2)
72- 76 F5.3 --- CaH1 The CaH1 spectral index (1)
77 A1 --- u_CaH1 [:] Unreliable value
80- 84 F5.3 --- CaH2 The CaH2 spectral index (1)
85 A1 --- u_CaH2 [:] Unreliable value
88- 92 F5.3 --- CaH3 The CaH3 spectral index (1)
96-100 F5.3 --- TiO5 The TiO5 spectral index (1)
101 A1 --- u_TiO5 [:] Unreliable value
104-107 F4.2 --- VOa The VOa spectral index (3)
108 A1 --- u_VOa [:] Unreliable value
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Note (1): The spectroscopic index defined in Reid et al., 1995, Cat. III/198
Note (2): The spectroscopic index defined in Martin et al. (1999AJ....118.2466M 1999AJ....118.2466M)
Note (3): The VOa index defined in Kirkpatrick et al. (1999ApJ...519..802K 1999ApJ...519..802K)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name The abbreviated DENIS name (except VB 10)
16 A1 --- n_Name [cd] Note on Name (1)
20- 23 F4.2 mag R-I R-I colour index computed from spectra
27- 31 F5.2 mag IMAG Absolute I band magnitude (2)
32 A1 --- r_IMAG [b] Reference for IMAG (3)
35- 39 F5.2 mag JMAG Absolute J band magnitude (2)
40 A1 --- r_JMAG [b] Reference for JMAG (3)
43- 47 F5.2 mag KMAG Absolute K band magnitude (2)
48 A1 --- r_KMAG [b] Reference for KMAG (3)
51- 54 F4.1 pc DistI Estimated distance from Mi
58- 61 F4.1 pc DistJ Estimated distance from Mj
65- 68 F4.1 pc DistK Estimated distance from Mk
72- 75 F4.1 pc Dist Adopted distance
76 A1 --- r_Dist [a] Reference for VB 10 Dist (4)
79- 82 F4.1 pc DistI-J Distance derived from the I-J colour (5)
86- 89 A4 --- SpTypeVOa Spectral type derived from the VOa index (6)
90 A1 --- u_SpTypeVOa [:] Unreliable value
93- 96 A4 --- SpTypeTiO5 Spectral type derived from the TiO5 index (6)
97 A1 --- u_SpTypeTiO5 [:] Unreliable value
100-103 A4 --- SpTypePC3 Spectral type derived from the PC3 index (7)
107-110 A4 --- SpType Adopted spectral type
114-117 F4.1 0.1nm EWHa Halpha equivalent width (in Angstroem)
118 A1 --- n_EWHa [*] * when EWHa is an upper limit
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Note (1): Notes on Name as follows:
c = also listed by Reid et al., 2003, Cat. J/AJ/126/3007
d = see Cruz et al., 2003, Cat. J/AJ/126/2421
Note (2): Estimated from the PC3-absolute magnitudes relation in
Crifo et al. (2005A&A...441..653C 2005A&A...441..653C)
Note (3): b = Optical and infrared photometry from Bessell, 1991AJ....101..662B 1991AJ....101..662B
Note (4): d=5.87pc, derived from π=170.3mas, a companion of
HIP 94761 (Cat. I/239)
Note (5): Using the formula given in Phan-Bao et al., 2003, Cat. J/A+A/401/959
Note (6): Using the formula given in Cruz & Reid, 2002, cat. J/AJ/123/2828
Note (7): Using the formula given in Martin et al., 1999AJ....118.2466M 1999AJ....118.2466M
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Acknowledgements: Ngoc Phan-Bao, pngoc(at)physics.ucf.edu
(End) Ngoc Phan-Bao [University of Central Florida, USA] 10-Mar-2006