J/ApJ/922/122 BVRcIc LCs of two contact binaries (Li+, 2021)
Two contact binaries with mass ratios close to the minimum mass ratio.
Li K., Xia Q.-Q., Kim C.-H., Hu S.-M., Guo D.-F., Jeong M.-J., Chen Xu,
Gao D.-Y.
<Astrophys. J., 922, 122 (2021)>
=2021ApJ...922..122L 2021ApJ...922..122L
ADC_Keywords: Binaries, eclipsing; Photometry, UBVRI
Keywords: Close binary stars ; Eclipsing binary stars ;
Stellar evolution ; Contact binary stars ; Mass ratio
Abstract:
The cutoff mass ratio is under debate for contact binaries. In this
paper, we present the investigation of two contact binaries with mass
ratios close to the low mass ratio limit. It is found that the mass
ratios of VSX J082700.8+462850 (hereafter J082700) and
1SWASP J132829.37+555246.1 (hereafter J132829) are both less than
0.1 (q∼0.055 for J082700 and q∼0.089 for J132829). J082700 is a
shallow contact binary with a contact degree of ∼19%, and J132829 is a
deep contact system with a fill-out factor of ∼70%. The O-C diagram
analysis indicated that the two systems manifested long-term period
decreases. In addition, J082700 exhibits a cyclic modulation which is
more likely resulting from the Applegate mechanism. In order to
explore the properties of extremely low mass ratio contact binaries
(ELMRCBs), we carried out a statistical analysis on contact binaries
with mass ratios of q∼0.1 and discovered that the values of Jspin/Jorb
of three systems are greater than 1/3. Two possible explanations can
interpret this phenomenon. One explanation is that some physical
processes, unknown to date, are not considered when Hut presented the
dynamic stability criterion. The other explanation is that the
dimensionless gyration radius (k) should be smaller than the value we
used (k2=0.06). We also found that the formation of ELMRCBs possibly
has two channels. The study of evolutionary states of ELMRCBs reveals
that their evolutionary states are similar with those of normal W UMa
contact binaries.
Description:
The multiple color light curves of VSX J082700.8+462850 (J082700) and
1SWASP J132829.37+555246.1 (J132829) were both observed in 2019 by
using 1.0m class telescopes. J082700 was observed using VRcIc filters
by the Weihai Observatory 1.0m telescope of Shandong University (WHOT
March 23, 25, and 31 (the seeing was around 1.7"). J132829 was
observed using BVRcIc filters by an 85cm telescope at the Xinglong
Station of National Astronomical Observatories (NAOs85cm) in China on
March 15 (the seeing was around 4.5") and by WHOT on April 25 and
May 2 (the seeing was around 2.0").
The scale of each image is approximately 0.35" per pixel for WHOT,
resulting in a field of view of about 12'x12', and the scale of each
image is approximately 0.94" per pixel for NAOs85cm, resulting in a
field of view of about 32'x32'.
Objects:
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RA (ICRS) DE Designation(s)
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08 27 00.82 +46 28 50.3 J082700 = CRTS J082700.8+462851
13 28 29.37 +55 52 46.0 J132829 = 1SWASP J132829.37+555246.1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1.dat 40 1940 Light curves of VSX J082700.8+462850 (J082700)
and 1SWASP J132829.37+555246.1 (J132829)
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See also:
II/287 : Northern Sky Variability Survey (NSVS) (Wozniak+, 2004)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/366 : ASAS-SN catalog of variable stars (Jayasinghe+, 2018-2020)
V/119 : Catalogue of field contact binary stars (Pribulla+, 2003)
J/ApJ/629/1055 : Evolution of close binary systems (Yakut+, 2005)
J/AJ/133/1470 : TAROT suspected variable star catalog (Damerdji+, 2007)
J/A+A/465/943 : BVI and RV curves of 5 eclipsing binaries (Szalai+, 2007)
J/MNRAS/405/1930 : Period changes of EA-, EB- & EW-types binaries (Liao+, 2010)
J/A+A/519/A78 : BVR light curves of KR Com (Zasche+, 2010)
J/MNRAS/412/1787 : Physical parameters of 62 eclipsing binaries (Deb+, 2011)
J/AJ/146/157 : Differential BVRI phot. of FI Boo (Christopoulou+, 2013)
J/AJ/145/100 : Differential BVR light curves of EP And (Lee+, 2013)
J/ApJS/208/9 : Colors and temperatures of PMS stars (Pecaut+, 2013)
J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/AJ/154/260 : 3 short-period eclipsing binaries BVRI phot. (Pi+, 2017)
J/AJ/157/207 : BVRcIc light curve observations for VZ Lib (Liao+, 2019)
J/ApJ/877/75 : BVRI phot. of DV Psc and known short-period EBs (Pi+, 2019)
Byte-by-byte Description of file: fig1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Star Star
9- 16 A8 --- Tel Telescope (1)
18- 19 A2 --- Filt Filter (B, V, Rc or Ic)
21- 33 F13.5 d HJD Heliocentric Julian Date of observation
35- 40 F6.3 mag dmag [-0.7/1.71] Differential magnitude in Filt
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Note (1): Telescope as follows:
NAOs85cm = an 85cm telescope at the Xinglong Station of National Astronomical
Observatories in China (836 occurrences)
WHOT = the Weihai Observatory 1.0m telescope of Shandong University
(1104 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Mar-2023