J/A+A/663/A115 Contact binary variables X-ray emission within 1kpc (Liu+, 2022)
The X-ray emission of contact binary variables within 1kpc.
Lui J., Wu J., Esamdin A., Gu W.-M., Sun M., Wang J.
<Astron. Astrophys. 663, A115 (2022)>
=2022A&A...663A.115L 2022A&A...663A.115L (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, X-ray ; Binaries, eclipsing ; Stars, variable ;
Stars, distances ; Effective temperatures ; Optical
Keywords: binaries: close - binaries: eclipsing - stars: variables: general -
X-ray: binaries
Abstract:
The X-ray emission of contact binaries (EW-type) is an important facet
of such systems. Thus, X-ray emitting EW-type binaries (EWXs) are
ideal laboratories for studying the X-ray radiation saturation
mechanisms as well as binary evolution. By assembling the largest
sample to date of EWXs with periods of less than 1 day from the
All-Sky Automated Survey for Supernovae Variable Stars Database and
X-ray catalogs from the XMM-Newton and ROSAT missions, we aim to
conduct a systematic population study of X-ray emission properties of
EWXs within 1 kpc.
We carried out correlation analyses for the X-ray luminosity,
logLX, and X-ray activity level log(LX/Lbol) versus the orbital
period, P, effective temperature, Teff, metallicity [Fe/H], and the
surface gravity logg of EWXs. We investigated the relation between
X-ray emission and the mass of component stars in the binary systems.
We also performed sample simulations to explore the degeneracy between
period, mass, and effective temperature for EWXs.
We find strong P-logLX and P-log(LX/Lbol) correlations for EWXs
with P≤0.44-days and we provide the linear parametrizations for these
relations, on the basis of which the orbital period can be treated as
a good predictor for log-LX and log(LX/Lbol). The aforementioned
binary stellar parameters are all correlated with log-LX, while only
Teff exhibits a strong correlation with log(LX/Lbol). Then, EWXs with
higher temperature show lower X-ray activity level, which could
indicate the thinning of the convective area related to the magnetic
dynamo mechanism. The total X-ray luminosity of an EWX is essentially
consistent with that of an X-ray saturated main sequence star with the
same mass as its primary, which may imply that the primary star
dominates the X-ray emission. The monotonically decreasing
P-log(LX/Lbol) relation and the short orbital periods indicate that
EWXs could all be in the X-ray saturated state, and they may inherit
the changing trend of the saturated X-ray luminosities along with the
mass shown by single stars. For EWXs, the orbital period, mass, and
effective temperature increase in concordance. We demonstrate that the
period P=0.44-days corresponds to the primary mass of ∼1.1M☉,
beyond which the saturated X-ray luminosity of single stars will not
continue to increase with mass. This explains the break in the
positive P-logLX relation for EWXs with P>0.44-days.
Description:
Parameters of 376 and 319 for EWXs date from the All-Sky Automated
Survey for Supernovae Variable Stars Database and X-ray catalogs from
the XMM-Newton (STW sample) and ROSAT missions (SRASS sample). Several
parameters of 139 EWXs with spectra from LAMOST DR7 (Spec-EWX sample).
Several parameters of 12279 X-ray luminosity upper limits from
XMM-Newton pointed and slew surveys for EW-type binaries. Several
parameters of 13769 X-ray luminosity upper limits from ROSAT survey
for EW-type binaries.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 142 376 Properties of EWXs in STW (Groups A, B and C)
table2.dat 69 319 Properties of objects in SRASS
table3.dat 72 139 Several parameters of EWXs in Spec-EWX sample
table4.dat 54 12279 Several parameters of X-ray luminosity upper
limits from XMM-Newton pointed and
slew surveys for EW-type binaries
table5.dat 54 13769 Several parameters of X-ray luminosity upper
limits from ROSAT survey for EW-type binaries
--------------------------------------------------------------------------------
See also:
II/366 : ASAS-SN catalog of variable stars (Jayasinghe+, 2018-2020)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Group [ABC] Group
3- 30 A28 --- ASAS-SN ASAS-SN identifier (JHHMMSS.ss+DDMMSS.s)
32- 40 F9.5 deg RAdeg Right Ascension (J2000)
42- 50 F9.5 deg DEdeg Declination (J2000)
52- 58 F7.5 d Per The interval of time between the
recurrence of phases in a periodic
phenomenon
60- 65 F6.4 mas Plx Gaia DR2 parallax
67- 72 F6.2 pc Dist Linear distance
74- 94 A21 --- 4XMM-DR9 Unique source name in 4XMM-DR9 catalog
96-101 F6.3 [10-7W] logLX X-ray Luminosity in 0.2-12keV band
103-112 A10 --- ATLASType Final ATLAS variable classification
114-120 A7 --- WISEType Final WISE variable classification
122-127 F6.3 mag AG ? Line-of-sight extinction in the G band
128 A1 --- n_AG [*] * for AG fixed to 0.600
(see Section 3.1 for details)
130-135 F6.3 [10-7W] logLbol ? Bolometric luminosity
137-142 F6.3 --- log(LX/Lbol) ? Ratio of X-ray luminosity to bolometric
luminosity
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension (J2000)
11- 19 F9.5 deg DEdeg Declination (J2000)
21- 27 F7.5 d Per The interval of time between the
recurrence of phases in a periodic
phenomenon
29- 34 F6.2 pc Dist Linear distance
36- 41 F6.3 [10-7W] logLX X-ray Luminosity in 0.2-12keV band
43- 47 F5.3 mag AG ? Line-of-sight extinction in the G band
48 A1 --- n_AG [*] * for AG fixed to 0.600
(see Section 3.1 for details)
50- 56 F7.3 [10-7W] logLbol ? Bolometric luminosity
58- 63 F6.3 --- log(LX/Lbol) ? Ratio of X-ray luminosity to bolometric
luminosity
65- 69 A5 --- Ref Reference (1)
--------------------------------------------------------------------------------
Note (1): References as follows:
1 = Stepien et al. (2001A&A...370..157S 2001A&A...370..157S)
2 = Geske et al. (2006AJ....131..633G 2006AJ....131..633G, Cat. J/AJ/131/633)
3 = Chen et al. (2006AJ....131..990C 2006AJ....131..990C)
4 = Duplication in STW
5 = This Work
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension (J2000)
11- 19 F9.5 deg DEdeg Declination (J2000)
21- 26 F6.3 [10-7W] logLX X-ray Luminosity in 0.2-12keV band
28- 34 F7.5 d Per The interval of time between the recurrence
of phases in a periodic phenomenon
36- 42 F7.2 K Teff Effective temperature from LAMOST DR7
44- 49 F6.2 K e_Teff The error of effective temperature
from LAMOST DR7
51- 56 F6.3 [-] [Fe/H] Metallicity from LAMOST DR7
58- 61 F4.2 [-] e_[Fe/H] The error of metallicity from LAMOST DR7
63- 67 F5.3 [cm/s2] logg The log surface gravity from LAMOST DR7
69- 72 F4.2 [cm/s2] e_logg The error of log surface gravity
from LAMOST DR7
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension (J2000)
11- 19 F9.5 deg DEdeg Declination (J2000)
21- 31 A11 --- Modes Missions operate in survey, slew and/or
pointed observation mode
33- 39 F7.5 d Per The interval of time between the recurrence
of phases in a periodic phenomenon
41- 46 F6.2 pc Dist Linear distance
48 A1 --- l_logLX Limit flag on logLX
49- 54 F6.3 [10-7W] logLX Upper limits of X-ray luminosity in
0.2-12keV band
--------------------------------------------------------------------------------
Acknowledgements:
Junhui Liu, wujianfeng(at)xmu.edu.cn
(End) Junhui Liu [Xiamen, Fujian, China], Patricia Vannier [CDS] 18-May-2022