J/AJ/128/426 Subdwarfs in the SDSS (West+, 2004)
Spectroscopic properties of cool stars in the Sloan Digital Sky Survey:
an analysis of magnetic activity and a search for subdwarfs.
West A.A., Hawley S.L., Walkowicz L.M., Covey K.R., Silvestri N.M.,
Raymond S.N., Harris H.C., Munn J.A., Mcgehee P.M., Ivezic Z., Brinkmann J.
<Astron. J., 128, 426-436 (2004)>
=2004AJ....128..426W 2004AJ....128..426W
ADC_Keywords: Stars, subdwarf ; Photometry, ugriz ; Equivalent widths
Keywords: Galaxy: structure - solar neighborhood - stars: activity -
stars: late-type - stars: low-mass, brown dwarfs - subdwarfs
Abstract:
We present a spectroscopic analysis of nearly 8000 late-type dwarfs in
the Sloan Digital Sky Survey. Using the Hα emission line as an
activity indicator, we investigate the fraction of active stars as a
function of spectral type and find a peak near type M8, confirming
previous results.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 70 60 Subdwarf data
--------------------------------------------------------------------------------
See also:
http://www.sdss.org : SDSS home page
J/AJ/113/806 : M-Subdwarfs (Gizis 1997)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS Object name
26- 30 F5.2 mag rmag ? SDSS r-band magnitude (1)
32- 36 F5.2 mag g-r ? SDSS (g-r) color (1)
38- 41 F4.2 mag r-i ? SDSS (r-i) color (1)
43- 46 F4.2 mag i-z ? SDSS (i-z) color (1)
48- 51 F4.2 --- TiO5 The TiO5 molecular band index
53- 56 F4.2 --- CaH1 The CaH1 molecular band index
58- 61 F4.2 --- CaH2 The CaH2 molecular band index
63- 67 F5.2 0.1nm EW ? Equivalent width of Hα in Angstroms (2)
69 I1 --- Sp The M spectral type subclass
--------------------------------------------------------------------------------
Note (1): Photometry is omitted when uncertainties are larger than 0.2mag.
Photometry is not available for some objects.
Note (2): EW of subdwarfs that were either classified as active or inactive
(see Section 3.2) are included.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 06-Oct-2005