J/A+A/364/205 UBVy photometry of cool stars (Cutispoto+, 2000)
Photometric and spectroscopic studies of cool stars discovered in EXOSAT X-ray
images. IV. The northern hemisphere sample.
Cutispoto G., Pastori L., Guerrero A., Tagliaferri G., Messina S.,
Rodono M., de Medeiros J.R.
<Astron. Astrophys. 364, 205 (2000)>
=2000A&A...364..205C 2000A&A...364..205C
ADC_Keywords: Photometry, UBV ; Stars, late-type ; X-ray sources ;
Radial velocities
Keywords: techniques: photometric - techniques: spectroscopic -
stars: abundances - stars: late-type - stars: variables: general -
X-rays: stars
Abstract:
We present high-precision photometry, high- and medium-resolution
spectroscopy for a sample of 32 stars likely to be the optical
counterparts of X-ray sources serendipitously detected by the EXOSAT
satellite. Using also recent results from the Hipparcos satellite, we
infer spectral types, compute X-ray luminosities and Li abundances and
investigate the single or binary nature of the sample stars. We found
eleven new variable stars, whose photometric periods fall in the
1.2-27.5 day range, for most of which the optical variability is
consistent with the presence of photospheric cool spots. For our
sample of X-ray selected stars we confirm the existence of a strong
correlation between the stellar rotation rate and the level of
activity, and also between the X-ray and bolometric luminosities. Two
stars in our sample are likely to be pre-main sequence objects, one is
likely to be a previously unknown M-type star within 25pc.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
stars.dat 60 33 Star positions and magnitudes (from Simbad)
ubvmag.dat 44 632 Complete UBV data set
ymag.dat 45 118 Complete y-band data set
table2.dat 95 32 Summary of stellar data
table3.dat 45 17 Radial velocities
tables.tex 79 142 LaTeX version of tables 2 & 3
--------------------------------------------------------------------------------
See also:
J/A+AS/115/41 : UBV(RI)c photometry of cool stars. (Cutispoto, 1996)
Byte-by-byte Description of file: stars.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Object name
21- 22 I2 h RAh Right ascension (J2000.0)
24- 25 I2 min RAm Right ascension (J2000.0)
27- 30 F4.1 s RAs Right ascension (J2000.0)
32 A1 --- DE- Declination sign (J2000.0)
33- 34 I2 deg DEd Declination (J2000.0)
36- 37 I2 arcmin DEm Declination (J2000.0)
39- 40 I2 arcsec DEs Declination (J2000.0)
44- 48 F5.2 mag Bmag ? B magnitude
50- 54 F5.2 mag Vmag ? V magnitude
56- 60 A5 --- SpType Spectral type
--------------------------------------------------------------------------------
Byte-by-byte Description of file: ubvmag.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Star name
12- 23 F12.4 d HJD Heliocentric Julian Day
25- 30 F6.3 mag Vmag V-band magnitude
32- 37 F6.3 mag B-V ?=9.999 B-V colour index
39- 44 F6.3 mag U-B ?=9.999 U-B colour index
--------------------------------------------------------------------------------
Byte-by-byte Description of file: ymag.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Star name
21- 32 F12.4 d HJD Heliocentric Julian Day
34- 39 F6.3 mag ymag Stromgren y-band star-comparison differential
magnitude in the instrumental system
41- 45 F5.3 mag e_ymag rms uncertainty on ymag
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Star name
20 A1 --- n_Name [*] *: faint stars whose spectral types were
evaluated from photographic plates data
22- 26 F5.2 mag Vmag V-band magnitude
27 A1 --- u_Vmag Uncertainty flag on Vmag
29- 44 A16 --- SpType spectral type inferred by us
45 A1 --- n_SpType [2] Note on SpType (1)
47- 49 I3 pc Dist Trigonometric or photometric (n_Dist = ":")
distance
50 A1 --- n_Dist [:] ':' for photometric distance
52 A1 --- l_EWLi Limit flag on EWLi
53- 55 I3 0.1pm EWLi ? Li I 6708 equivalent width
57 A1 --- n_EWLi [yn 1] Note on EWLI (1)
59- 60 A2 --- Halpha [ae pf] H alpha line detection flag (1)
62- 63 A2 --- CaII [ae ?] Ca II H&K lines detection flag (1)
65 A1 --- l_Per Limit flag on Per
66- 70 F5.2 d Per ? Period of photometric variability
71 A1 --- u_Per [?] Uncertainty flag on Pper
73- 74 I2 km/s vsini ? Rotational velocity
75 A1 --- u_vsini Uncertainty flag on vsini
76 A1 --- n_vsini [1/3] Note on vsini
78- 81 F4.1 [10+23W] logLX ? log of X-ray luminosity (in 1030erg/s)
from the ROSAT PSPC
83- 86 F4.1 [10+23W] logLXe ? log of X-ray luminosity (in 1030erg/s)
from the EXOSAT CMA
88 A1 --- l_logALi Limit flag on logALi
89- 93 F5.2 --- logALi ? Li abundance in logarithmic scale
(H abundance = 12)
94 A1 --- n_logALi [1] Note on logALi (1)
--------------------------------------------------------------------------------
Note (1): Flags and notes:
n: line not detectable
y: line detectable
a: absorption line
pf: line partially filled-in by emission
f: line filled-in by emission
e: emission line
1: SB2 system, Li EW = 55 mÅ for both components,
vsini = 12 and 7km/s, ALi = 2.7 and 2.6;
2: visual binary, both stars are constituted by M1V + M3:V components
3: SB 2, vsini = 50: and 30: km/s
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Star name
12- 23 F12.4 d HJD Heliocentric Julian Day
25- 29 F5.1 km/s RV Radial velocity value
31- 33 F3.1 km/s e_RV rms uncertainty on RV
35- 36 I2 --- o_RV Number of lines used for RV computation
38- 45 A8 --- SR Spectral region, Li (= Li I 6708) or Halpha
--------------------------------------------------------------------------------
Acknowledgements: Giuseppe Cutispoto
History:
31-Jan-2001: Positions of EXO sources corrected in file stars.dat
References:
Cutispoto at al., Paper I 1991A&AS...87..233C 1991A&AS...87..233C
Tagliaferri et al., Paper II 1994A&A...285..272T 1994A&A...285..272T
Cutispoto et al., Paper III 1996A&AS..115...41C 1996A&AS..115...41C, Cat. J/A+AS/115/41
(End) Patricia Bauer [CDS] 18-Dec-2000