J/AJ/167/18 Period variations of 32 contact binaries (Hong+, 2024)
Improved Period Variations of 32 Contact Binaries with Rapidly Decreasing
Periods in the Galactic Bulge.
Hong K., Lee J.W., Kim D.-J., Park J.-H., Kim H.-Y., Rittipruk P., Han C.
<Astron. J., 167, 18 (2024)>
=2024AJ....167...18H 2024AJ....167...18H
ADC_Keywords: Binaries, eclipsing; Galactic center; Spectra, optical
Keywords: Contact binary stars ; Eclipsing binary minima timing method ;
Eclipsing binary stars ; Galactic bulge ; Stellar mergers
Abstract:
We present detailed analyses of updated eclipse timing diagrams for 32
contact binary merger candidates in the Galactic bulge. The
photometric data was obtained from 2016 to 2021 using the Korea
Microlensing Telescope Network with the 1.6 m telescopes located at
three southern sites (CTIO, SAAO, and SSO). The times of minimum
lights were determined by applying the binary-star model to full light
curves created at half-year intervals from the observations. The
orbital period variations of the binary systems were analyzed using
the O-C diagrams from our new timings with the others published in the
literature, which are based on the OGLE observations from 2001 to
2015. As results, the orbital periods and period-decreasing rates of
32 binary systems were located to be in the ranges of 0.370 to 1.238
days and from -3.0 to -13.1x10-6day/yr, respectively. Out of these
stars, 24 systems show a combination effect of a parabola and a light
travel time caused by a third body, and their outer orbital periods
are in the range of 9.1-26.5yr. We propose that all of our merger
candidates need additional monitoring observations to study a
luminous-red nova progenitor.
Description:
The KMTNet observations were monitored with an exposure time of
2minutes using the 1.6m wide field optical telescopes at three sites;
the Siding Spring Observatory in Australia, Cerro Tololo Interamerican
Observatory in Chile, and the South African Astronomical Observatory
in South Africa.
The OGLE-III&IV observations were carried out between 2001 and 2015
toward the Galactic bulge using the 1.3m telescope located at the Las
Campanas Observatory in Chile. The sky coverages of the OGLE-III
(2001-2009) and OGLE-IV (2010-2015) were about 92deg2 and 182deg2
of the Galactic bulge, respectively. Most of the observations were
taken in I-band, and some V-band images were acquired for the color
measurement.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 63 274 List of eclipse timings for 8 CEBs showing a
parabolic variation
table5.dat 75 1262 List of eclipse timings of 24 CEBs with the
parabolic plus LTT ephemeris
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See also:
J/A+A/289/871 : YY Eri & AE Phe (Maceroni+, 1994)
J/AJ/147/91 : Differential BVR light curves of V407 Peg (Lee+, 2014)
J/AcA/66/405 : Galactic bulge eclipsing & ellipsoid binary (Soszynski+, 2016)
J/AJ/158/185 : 3 binary systems in the Large Magellanic Cloud (Hong+, 2019)
J/A+A/630/A75 : Six luminous red novae photometry (Pastorello+, 2019)
J/AJ/163/157 : 14127 eclipsing binaries in the Galactic Bulge (Hong+, 2022)
J/AJ/164/202 : Extremely Low Mass Ratio Contact Binaries. I. (Li+, 2022)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name OGLE name; OGLE-BLG-
12- 20 F9.4 d HJD [2450/9442] Heliocentric Julian Date HJD-2450000
22- 27 F6.4 d e_HJD [0.001/0.02] Uncertainty in HJD
29- 33 I5 --- Cycle [-7704/4134] Cycle of binary system
35- 42 F8.5 d O-C1 [-0.28/0.008] O-C1 value (1)
44- 51 F8.5 d O-C2 [-0.03/0.02] O-C2 value (1)
53- 58 A6 --- Inst Instrument used
60- 63 I4 --- Nobs [31/2016] Number of observations
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Note (1): Observed time of minimum light minus those calculated according to
an adopted ephemeris. See equations 1 and 2.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name OGLE name; OGLE-BLG-
12- 20 F9.4 d HJD [2133/9441] Heliocentric Julian Date HJD-2450000
22- 27 F6.4 d e_HJD [0.0002/0.01] Uncertainty in HJD
29- 36 F8.1 --- Cycle [-11230/6597] Cycle of binary system
38- 45 F8.5 d O-C1 [-0.19/0.03] O-C1 value (1)
47- 54 F8.5 d O-C2 [-0.05/0.04] O-C2 value (1)
56- 63 F8.5 d O-C3 [-0.02/0.02] O-C3 value (1)
65- 70 A6 --- Inst Instrument used
72- 75 I4 --- Nobs [31/2350] Number of observations
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Note (1): Observed time of minimum light minus those calculated according to
an adopted ephemeris. See equations 1, 2, and 3.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 19-Apr-2024