J/A+A/433/151 Spectroscopic results on ROSAT late-type stars (Zickgraf+, 2005)
Identification of a complete sample of northern ROSAT All-Sky Survey X-ray
sources. VIII. The late-type stellar component.
Zickgraf F.-J., Krautter J., Reffert S., Alcala J.M., Mujica R., Covino E.,
Sterzik M.F.
<Astron. Astrophys., 433, 151-171 (2005)>
=2005A&A...433..151Z 2005A&A...433..151Z
ADC_Keywords: X-ray sources ; Stars, late-type ; Abundances ;
Radial velocities ; Space velocities ; Proper motions
Keywords: surveys - X-rays: stars - stars: late-type -
stars: pre-main sequence - stars: kinematics - solar neighbourhood
Abstract:
We present results of an investigation of the X-ray properties, age
distribution, and kinematical characteristics of a high-galactic
latitude sample of late-type field stars selected from the ROSAT
All-Sky Survey (RASS). The sample comprises 254 RASS sources with
optical counterparts of spectral types F to M distributed over six
study areas located at |b|≳20°, and Dec≥-9°. A detailed
study was carried out for the subsample of ∼200 G, K, and M stars.
Lithium abundances were determined for 179 G-M stars. Radial
velocities were measured for most of the 141 G and K type stars of the
sample. Combined with proper motions these data were used to study the
age distribution and the kinematical properties of the sample. Based
on the lithium abundances half of the G-K stars were found to be
younger than the Hyades (660Myr). About 25% are comparable in age to
the Pleiades (100Myr). A small subsample of 10 stars is younger than
the Pleiades. They are therefore most likely pre-main sequence stars.
Kinematically the PMS and Pleiades-type stars appear to form a group
with space velocities close to the Castor moving group but clearly
distinct from the Local Association.
Description:
Paper III (Appenzeller et al., 1998, Cat. J/ApJS/117/319) presents a
catalogue of optical identifications for 685 RASS sources contained in
six study areas. The catalogue contains 254 X-ray sources which have
been identified as coronal emitters of spectral types F to M.
The stellar sample of G to M above was observed spectroscopically
during several observing runs. Low-resolution spectra were obtained
with CAFOS, high-resolution spectra were observed with FOCES, both
attached to the 2.2m telescope at Calar Alto observatory (CA), Spain.
Further high- and medium-resolution observations were obtained at the
Observatoire de Haute Provence (OHP), France, with the spectrographs
AURELIE and CARELEC at the 1.52m and 1.93m telescopes, respectively.
A few supplementary high- and low-resolution observations were
obtained at European Southern Observatory, La Silla, Chile (ESO), with
CASPEC at the ESO 3.6m telescope and DFOSC at the Danish 1.54m
telescope, respectively. A further observing run of 5 nights at Calar
Alto observatory in February 2001 was lost due to bad weather
conditions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea2.dat 80 205 Basic optical and X-ray parameters of the
sample of G-, K-, and M-type stars.
tablea3.dat 93 205 Kinematical parameters
tablea4.dat 42 205 Lithium abundances and rotational velocities
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See also:
J/ApJS/117/319 : Northern RASS X-ray sources catalog (Appenzeller+ 1998)
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- [ATZ98] Source name
6- 20 A15 --- RXJ RASS name (RX JHHMM.m+DDMM)
22- 23 I2 h RAh Right ascension (J2000)
25- 26 I2 min RAm Right ascension (J2000)
28- 31 F4.1 s RAs Right ascension (J2000)
33 A1 --- DE- Declination sign (J2000)
34- 35 I2 deg DEd Declination (J2000)
37- 38 I2 arcmin DEm Declination (J2000)
40- 41 I2 arcsec DEs Declination (J2000)
43- 50 A8 --- SpType MK spectral type
52- 54 A3 --- SB Spectroscopic binary type (SB2 or SB3)
56- 60 F5.2 mag Vmag ?=- V magnitude
62- 66 F5.2 [-] logFx/Fv ?=- X to visual flux ratio
68- 71 I4 pc Dist ?=- Heliocentric distance
72 A1 --- u_Dist Uncertainty flag on Diat
74 A1 --- n_Dist [MISTH] Method from which the distance
was calculated (1)
76- 80 F5.2 10-7W logLx ?=- X-ray luminosity calculated using the
distance Dist
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Note (1): Method from which the distance was calculated as follows:
S = spectroscopy
H = Hipparcos
T = trigonometric parallaxes
I = infrared colours
M = assuming luminosity class V
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Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- [ATZ98] Source name
6- 13 A8 --- SpType MK spectral type type
15- 18 I4 km/s HRV1 ?=- Heliocentric radial velocity
(of the primary for binaries)
20- 21 I2 km/s e_HRV1 ?=- rms uncertainty on HRV1
23- 26 I4 km/s HRV2 ?=- Heliocentric radial velocity of the
secondary for binaries
28 I1 km/s e_HRV2 ?=- rms uncertainty on HRV2
30- 36 F7.1 mas/yr pmRA ?=- Proper motion, µαcosδ
38- 41 F4.1 mas/yr e_pmRA ?=- rms uncertainty on pmRA
43- 49 F7.1 mas/yr pmDE ?=- Proper motion, µδ
51- 54 F4.1 mas/yr e_pmDE ?=- rms uncertainty on pmDE
56- 57 A2 --- r_pmRA Source of the proper motion (1)
59- 64 F6.1 km/s UVel ?=- U velocity
66- 69 F4.1 km/s e_UVel ?=- rms uncertainty on UVel
71- 76 F6.1 km/s VVel ?=- V velocity
78- 81 F4.1 km/s e_VVel ?=- rms uncertainty on VVel
83- 88 F6.1 km/s WVel ?=- W velocity
90- 93 F4.1 km/s e_WVel ?=- rms uncertainty on WVel
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Note (1): Source of the proper motions as follows:
TY = Tycho-2, Cat. I/259
HI = Hipparcos, Cat. I/239
UC = UCAC2, Cat. I/289
US = USNO-B1.0, Cat. I/284
PP = PPM, Cat. I/146 & I/193
ST = STARNET, cat. I/253
TR = TRC, Cat. I/250
NL = NLPM1
CA = Carlsberg Meridian Catalogs, Cat. I/256
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- [ATZ98] Source name
6- 13 A8 --- SpType MK spectral type
16- 19 I4 K Teff Effective temperature
21 A1 --- l_EW Limit flag on EW
22- 24 I3 0.1pm EW ?=- LiI (6708Å) equivalent width
26 A1 --- Res [hlm-] (h)igh, (m)edium or (l)ow resolution
spectroscopy
28 A1 --- l_logN(Li) Limit flag on logN(Li)
29- 33 F5.2 --- logN(Li) ?=- Li abundance (H=12)
35 A1 --- l_vrot1 Limit flag on vrot1
36- 38 I3 km/s vrot1 ?=- Rotational velocity
(of the primary for binaries)
40- 42 I3 km/s vrot2 ?=- Rotational velocity of the secondary
for binaries
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History:
* 11-Aug-2006: From electronic version of the journal
* 12-Dec-2006: in the 3 tables, D114 appears twice in records
#142 and #143, the first having an erroneous RA.
References:
Zickgraf et al. Paper I 1998AN....319...42Z 1998AN....319...42Z
Zickgraf et al. Paper II 1997A&AS..123..103Z 1997A&AS..123..103Z
Appenzeller et al., Paper III 1998ApJS..117..319A 1998ApJS..117..319A, Cat. J/ApJS/117/319
Krautter et al. Paper IV 1999A&A...350..743K 1999A&A...350..743K
Zickgraf et al. Paper V 1997A&A...323L..21Z 1997A&A...323L..21Z
Zickgraf et al. Paper VI 1998A&A...339..457Z 1998A&A...339..457Z
Appenzeller et al., Paper VII 2000A&A...364..443A 2000A&A...364..443A
(End) Patricia Vannier [CDS] 11-Aug-2006