J/AJ/132/866 New M dwarfs in solar neighborhood (Riaz+, 2006)
Identification of new M dwarfs in the solar neighborhood.
Riaz B., Gizis J.E., Harvin J.
<Astron. J., 132, 866-872 (2006)>
=2006AJ....132..866R 2006AJ....132..866R
ADC_Keywords: Stars, nearby ; Stars, M-type ; Photometry, infrared
Keywords: stars: activity - stars: fundamental parameters - stars: late-type -
X-rays: stars
Abstract:
We present the results from a spectroscopic study of 1063 nearby
active M dwarfs, selected by correlating the Two Micron All Sky Survey
and ROSAT catalogs. We have derived the spectral types and estimated
distances for all of our stars. The spectral types range between K5
and M6. Nearly half of our stars lie within 50pc. We have measured the
equivalent width of the Hα emission line. Our targets show an
increase in chromospheric activity from early to midspectral types,
with a peak in activity around M5. Using the count rate and hardness
ratios obtained from the ROSAT catalog, we have derived the X-ray
luminosities. Our stars display a "saturation-type" relation between
the chromospheric and coronal activity. The relation is such that
log(LX/Lbol) remains "saturated" at a value of approximately -3 for
varying Hα equivalent width. We have found 568 matches in the
USNO-B catalog and have derived the tangential velocities for these
stars. There is a slight trend of decreasing chromospheric activity
with age, such that the stars with higher vtan have lower Hα
equivalent widths. The coronal emission, however, remains saturated at
a value of log(LX/Lbol)~-3 for varying tangential velocities,
suggesting that the coronal activity remains saturated with age. We do
not find any break in the saturation-type relation at the spectral
type at which stars become fully convective (∼M3.5). Most of the stars
in our sample show more coronal emission than the dMe stars in the
Hyades and Praesepe and have vtan<40km/s, suggesting a young
population.
Description:
We have obtained medium-resolution infrared spectra of the stars in
our sample using the Palomar 60 inch (1.5m) telescope for the northern
stars and the Cerro Tololo Inter-American Observatory 1.5m telescope
for the southern hemisphere stars. Data from the Palomar 60inch were
obtained in 2000 October and November and in 2001 June.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 113 1063 Observed and derived quantities of nearby M stars
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2M The 2MASS identification (1)
18- 21 F4.2 --- CaH1 ? The CaH1 index
23- 26 F4.2 --- CaH2 ? The CaH2 index
28- 31 F4.2 --- CaH3 ? The CaH3 index
33- 36 F4.2 --- TiO5 The TiO5 index (bandheads at 650 and 705nm)
38- 42 F5.2 mag Jmag 2MASS J band magnitude
44- 48 F5.2 mag Hmag 2MASS H band magnitude
50- 54 F5.2 mag Kmag 2MASS K band magnitude
56- 59 A4 --- SpType MK spectral type, mainly from TiO5 index
61- 65 F5.1 0.1nm EWHa ? Hα equivalent width in Angstroms
67- 71 F5.2 [-] log(LX/Lbol) Log of the X-ray to Bolometric luminosities
73- 75 I3 km/s Vtan ? Tangential velocity
77- 80 I4 pc Dist Spectroscopic distance
82- 83 I2 pc pDist ? Distance from parallax
85-113 A29 --- OName Other name(s) of the star (2)
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Note (1): Format is HHMMSSs+DDMMSS for 2MASS-I = Cat. II/241,
or HHMMSSss+DDMMSSs for 2MASS-Final = Cat. II/246.
Note (2): errors detected and corrected at CDS are marked (*), see the
"History" section below.
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History:
* 08-Feb-2008: From electronic version of the journal
Table 1 from erratum, 2007, AJ, 133, 1208
* 07-Jul-2009: Wrong identifications in column 'OName' corrected at CDS;
errors are marked with (*) in the 'OName' column and concern:
* CE 102 which was indicated 03360868+3118398 but
CE 102 = 09455843-3253299
* BPS CS 22939-0062 was assigned to 2 stars 19222035-2754587 and
19222935-2754587 but BPS CS 22939-0062 = 19214521-1948136
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 08-Feb-2008