J/other/RAA/20.163 Contact binaries in LAMOST DR7 (Qian+, 2020)
Contact binaries at different evolutionary stages.
Qian S.-B., Zhu L.-Y., Liu L., Zhang X.-D., Shi X.-D., He J.-J., Zhang J.
<Res. Astron. Astrophys., 20, 163 (2020)>
=2020RAA....20..163Q 2020RAA....20..163Q (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Effective temperatures ;
Abundances, [Fe/H] ; Radial velocities ; Optical
Abstract:
Contact binaries consist of two strongly interacting component stars
where they are filling their critical Roche lobes and sharing a common
envelope. Most of them are main-sequence stars, but some of them are
post main-sequence systems. They are good astrophysical laboratories
for studying several problems such as the merging of binary stars,
evolution of the common envelope, the origin of luminous red nova
outbursts and the formation of rapidly rotating single stars with
possible planetary systems. A large number of contact binary
candidates were detected by several photometric surveys around the
world and many of them were observed by the LAMOST spectroscopic
survey. Based on follow-up observations, the evolutionary states and
geometrical structures of some systems were understood well. In this
review, we will introduce and catalog new stellar atmospheric
parameters (i.e., the effective temperature (Teff), the gravitational
acceleration (log(g)), metallicity ([Fe/H]) and radial velocity (Vr))
for 9149 EW-type contact binaries that were obtained based on low- and
medium-resolution spectroscopic surveys of LAMOST. Then we will focus
on several groups of contact binary stars, i.e., marginal contact
binary systems, deep and low-mass ratio contact binary stars, binary
systems below the short-period limit of contact binaries and evolved
contact binaries. Marginal contact binaries are at the beginning of
the contact stage, while deep and low-mass ratio contact binary stars
are at the final evolutionary stage of tidally locked binaries.
Several statistical relations including the period-temperature
relation are determined well by applying LAMOST data and their
formation and evolutionary states are reviewed. The period-color
relation of M-type binaries reveals that there are contact binaries
below the short-period limit. Searching for and investigating contact
binaries near and below this limit will help us to understand the
formation of contact binary systems and a new prediction for the
short-period limit is about 0.15 d. Some evolved contact binaries were
detected by the LAMOST survey where both components are sub-giants or
giants. They provide a good opportunity to investigate evolution of
the common envelope and are the progenitors of luminous red novae like
V1309 Sco.
Description:
Since the investigation by Qian et al. (2017RAA....17...87Q 2017RAA....17...87Q), many
EW-type contact binaries were observed in the LAMOST spectroscopic
survey. On 2020 May 7, data from LAMOST Data Release 7 (DR7) V1.1 were
released which include observations in the time interval from 2011
October 24 to 2019 June 8. A total of 10602012 LRS were obtained and
9529826 of them are stellar spectra. Meanwhile, 3856218
medium-resolution stellar spectra were acquired. In LAMOST DR7 V1.1,
stellar atmospheric parameters of 8520 EW-type contact binaries were
determined by LRS, while the parameters of 629 ones were procured by
medium-resolution spectra (MRS). Those stellar atmospheric parameters
include the effective temperature Teff, the gravitational acceleration
log(g), metallicity [Fe/H] and radial velocity Vr. They were
automatically determined by the LAMOST stellar parameter pipeline when
their spectra were regarded as good and reliable (e.g., Wu et al.
2011RAA....11..924W 2011RAA....11..924W (Cat. J/other/RAA/11.924), 2014, IAU Symposium,
306, 340; Luo et al. 2015RAA....15.1095L 2015RAA....15.1095L).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 115 8520 Mean stellar atmospheric parameters of
EWs observed in LSR
table4.dat 115 629 Mean stellar atmospheric parameters of
EWs observed in MRS
table1.dat 151 12355 Catalog of stellar atmospheric parameters for
8520 EWs determined with LRS
table2.dat 151 1089 Catalog of stellar atmospheric parameters for
629 EWs determined with MRS
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See also:
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
http://dr7.lamost.org : LAMOST DR7 Home Page
Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 30 A30 --- Name Variable star identifier
32- 33 I2 h RAh Right ascension (J2000.0)
34- 35 I2 min RAm Right ascension (J2000.0)
36- 40 F5.2 s RAs Right ascension (J2000.0)
42 A1 --- DE- Declination sign (J2000.0)
43- 44 I2 deg DEd Declination (J2000.0)
45- 46 I2 arcmin DEm Declination (J2000.0)
47- 50 F4.1 arcsec DEs Declination (J2000.0)
52- 64 F13.9 d Porb ? Orbital period
67 A1 --- u_Porb Uncertainty flag on Porb
68- 69 I2 --- N The observed times by LAMOST
71- 75 A5 --- SpType The mean value of spectral type
77- 83 F7.2 K Teff The mean value of the effective temperature
84- 90 F7.2 K e_Teff ?=- The mean value of the error of the
effective temperature
92- 96 F5.3 [cm/s2] logg The mean value of the gravitational
acceleration
98-102 F5.3 [cm/s2] e_logg ?=- The mean value of the error of the
gravitational acceleration Log(g)
104-109 F6.3 [-] [Fe/H] The mean value of metallicity
111-115 F5.3 [-] e_[Fe/H] ?=- The mean value of the error of
Metallicity
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Byte-by-byte Description of file: table1.dat table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 30 A30 --- Name Variable star identifier
32- 33 I2 h RAh Right ascension (J2000.0)
34- 35 I2 min RAm Right ascension (J2000.0)
36- 40 F5.2 s RAs Right ascension (J2000.0)
42 A1 --- DE- Declination sign (J2000.0)
43- 44 I2 deg DEd Declination (J2000.0)
45- 46 I2 arcmin DEm Declination (J2000.0)
47- 50 F4.1 arcsec DEs Declination (J2000.0)
52- 58 A7 --- Type Variability type, as in GCVS catalog
60- 74 F15.9 d Porb ?=- Orbital period
79 A1 --- u_Porb Uncertainty flag on Porb
82- 91 A10 --- Date Observed date
93- 97 A5 --- SpType Spectral type (only in table1)
99-105 F7.2 K Teff The effective temperature
107-112 F6.2 K e_Teff The error of the effective temperature
114-118 F5.3 [cm/s2] logg The gravitational acceleration log(g)
120-124 F5.3 [cm/s2] e_logg ?=- The error of the gravitational
acceleration log(g)
126-131 F6.3 [-] [Fe/H] Metallicity
133-137 F5.3 [-] e_[Fe/H] ?=- The error of Metallicity
139-145 F7.2 km/s RV Radial velocity (only in table1)
146-151 F6.2 km/s e_RV ?=999 The error of radial velocity
(only in table1)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Feb-2022