J/AJ/156/199 CCD observations in BVRI bands for TY Pup (Sarotsakulchai+, 2018)
TY Pup: a low-mass-ratio and deep contact binary as a progenitor candidate
of luminous red novae.
Sarotsakulchai T., Qian S.-B., Soonthornthum B., Zhou X., Zhang J.,
Reichart D.E., Haislip J.B., Kouprianov V.V., Poshyachinda S.
<Astron. J., 156, 199 (2018)>
=2018AJ....156..199S 2018AJ....156..199S (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Photometry, UBVRI
Keywords: binaries: close - binaries: eclipsing - stars: evolution -
stars: individual (TY Pup)
Abstract:
TY Pup is a well-known bright eclipsing binary with an orbital period
of 0.8192 days. New light curves in B, V, (RI)C bands were obtained
with the 0.61 m reflector robotic telescope (PROMPT-8) at CTIO in Chile
during 2015 and 2017. By analyzing those photometric data with the W-D
method, it is found that TY Pup is a low-mass-ratio (q∼0.184) and
deep-contact binary with a high fill-out factor (84.3%). An investigation
of all available times of minimum light including three new ones obtained
with the 60 cm and the 1.0 m telescopes at Yunnan Observatories in
China indicates that the period change of TY Pup is complex. An upward
parabolic variation in the O-C diagram is detected to be superimposed
on a cyclic oscillation. The upward parabolic change reveals a long-term
continuous increase in the orbital period at a rate of
dP/dt=5.57(±0.08)x10-8 days/yr. The period increase can be explained
by mass transfer from the less massive component (M2∼0.3 M☉) to
the more massive one (M1∼1.65 M☉). The binary will be merging
when it meets the criterion that the orbital angular momentum is less
than three times the total spin angular momentum, i.e., Jorb<3Jrot.
This suggests that the system will finally merge into a rapid-rotating
single star and may produce a luminous red nova. The cyclic oscillation
in the O-C diagram can be interpreted by the light-travel time effect
via the presence of a third body.
Description:
The first set of light curves of TY Pup in BV(RI)C bands were carried
out for several nights from 2015 January to February with the back
illuminated Apogee F42 2048x2048 CCD attached to the 0.6 m Cassegrain
reflecting telescope of PROMPT-8 robotic telescope. The telescope is
located at the Cerro Tololo Inter-American Observatory (CTIO) in Chile.
The web-based SKYNET client allowed us to request and retrieve image
remotely via the internet. SKYNET system also provided nightly calibration
images, including bias, dark, and flat-field images (Layden & Broderick
2010PASP..122.1000L 2010PASP..122.1000L). All CCD reductions and aperture photometry
measurements were done with standard procedure packages of IRAF. The
second set of light curves were obtained from 2017 March to April. To
obtain more times of light minimum, TY Pup was also monitored by using
the 60 cm and 1.0 m telescopes of Yunnan Observatories (YNOs) in 2015
February and 2018 January, respectively. These telescopes were equipped
with a Cassegrain-focus multicolor CCD photometer where an Andor DW436 2 K
CCD camera. Standard Johnson-Cousin-Bessel BV(RI)C filters were used.
Objects:
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RA (ICRS) DE Designation(s) (Period)
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07 32 46.23 -20 47 31.1 TY Pup = V* TY Pup (P=0.8192)
07 33 10.22 -20 42 13.2 HD 60342 = 2MASS J07331022-2042130
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 58 240 CCD observations in BVRI bands for TY Pup observed
in 2015
table3.dat 58 240 CCD observations in BVRI bands for TY Pup observed
in 2017
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See also:
J/A+A/311/523 : Photometry of W UMa (Maceroni+, 1996)
J/MNRAS/357/497 : Kinematics of W UMa-type binaries (Bilir+, 2005)
J/AJ/134/2353 : Observations of contact binaries (Rucinski+, 2007)
J/MNRAS/412/1787 : Physical parameters of 62 eclipsing binaries
(Deb+, 2011)
J/AJ/143/99 : Photometry of W UMa eclipsing binaries (Terrell+, 2012)
J/AJ/146/70 : Spectroscopy of W UMa-type binary stars
(Rucinski+, 2013)
J/other/RMxAA/53.235 : Photometry of 6 deep-contact W UMa (Kjurkchieva+, 2017)
Byte-by-byte Description of file: table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 7 F7.4 d HJD-B [33.6422/51.6432] Heliocentric observation date
of B band (HJD-2457000)
9- 13 F5.3 mag DBmag [0.158/0.642] B band magnitude difference between
variable and comparison (HD 60342) stars
15- 21 F7.4 d HJD-V [33.6425/52.515] Heliocentric observation date
of V band (HJD-2457000)
23- 28 F6.3 mag DVmag [-0.286/0.213] V band magnitude difference between
variable and comparison (HD 60342) stars
30- 36 F7.4 d HJD-R [33.6427/51.6504] Heliocentric observation date
of RC band (HJD-2457000)
38- 43 F6.3 mag DRmag [-0.537/-0.061] RC band magnitude difference
between variable and comparison (HD 60342) stars
45- 51 F7.4 d HJD-I [33.643/52.5376] Heliocentric observation date
of IC band (HJD-2457000)
53- 58 F6.3 mag DImag [-0.77/-0.298] IC band magnitude difference
between variable and comparison (HD 60342) stars
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 28-Mar-2019