J/AJ/148/90 Differential VRI photometry of WW Gem (Yang+, 2014)
WW Geminorum: an early B-type eclipsing binary evolving into the contact phase.
Yang Y.-G., Yang Y., Dai H.-F., Yin X.-G.
<Astron. J., 148, 90 (2014)>
=2014AJ....148...90Y 2014AJ....148...90Y
ADC_Keywords: Binaries, eclipsing ; Photometry, UBVRI
Keywords: binaries: close - binaries: eclipsing - stars: individual: WW Gem
Abstract:
WW Gem is a B-type eclipsing binary with a period of 1.2378days. The
CCD photometry of this binary was performed in 2013 December using the
85cm telescope at the Xinglong Stations of the National Astronomical
Observatories of China. Using the updated W-D program, the photometric
model was deduced from the VRI light curves. The results imply that WW
Gem is a near-contact eclipsing binary whose primary component almost
fills its Roche lobe. The photometric mass ratio is
qph=0.48(±0.05). All collected times of minimum light, including
two new ones, were used for the period studies. The orbital period
changes of WW Gem could be described by an upward parabola, possibly
overlaid by a light-time orbit with a period of Pmod=7.41(±0.04)yr
and a semi-amplitude of A=0.0079days(±0.0005days), respectively.
This kind of cyclic oscillation may be attributed to the light-travel
time effect via the third body. The long-term period increases at a
rate of dP/dt=+3.47(±0.04)x10-8day/yr, which may be explained by
the conserved mass transfer from the less massive component to the
more massive one. With mass transfer, the massive binary WW Gem may be
evolving into a contact binary.
Description:
The multi-color photometry of WW Gem was acquired on 2013 December, by
using the 85cm telescope at the Xinglong Station (XLs) of the National
Astronomical Observatories of China (NAOC).
Objects:
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RA (ICRS) DE Designation(s) (Period)
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06 12 05.78 +23 30 03.3 WW Geminorum = HD 253102 (P=1.23781)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 939 VRI photometric observations of WW Gem in 2013
table2.dat 54 133 All compiled times of minimum light of the
early-type eclipsing binary WW Gem
refs.dat 85 58 References
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
J/AJ/147/145 : Algol-type binaries. VIII. DI Peg & AF Gem (Yang+, 2014)
J/AJ/145/9 : BVRI light curves of V382 Cyg (Yasarsoy+, 2013)
J/AJ/143/122 : VR light curves of CK Boo (Yang+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD-V ? V band Heliocentric Julian Date
14- 19 F6.3 mag DVmag ? Differential V band magnitude
21- 32 F12.4 d HJD-R ? R band Heliocentric Julian Date
34- 39 F6.3 mag DRmag ? Differential R band magnitude
41- 52 F12.4 d HJD-I ? I band Heliocentric Julian Date
54- 59 F6.3 mag DImag ? Differential I band magnitude
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian Date
14- 20 F7.1 --- Epoch Epoch
22- 24 A3 --- Meth Observational method used (vi=visual, CCD,
pe=photoelectric, p=plate, pg=photographic)
26- 27 A2 --- Type Minimum type (I or II)
29- 35 F7.4 d O-C1 Eclipse time residual (O-C)1 (1)
37- 43 F7.4 d O-C2 Eclipse time residual (O-C)2 (2)
45- 51 F7.4 d O-C3 ? Eclipse time residual (O-C)3 (3)
53- 54 I2 --- Ref Reference; in refs.dat file
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Note (1): Computed with a linear ephemeris given by Kreiner et al.
(2001aocd.book.....K 2001aocd.book.....K), Min.I=HJD2425984.2593+1.23781135*E
(Equation (1) in the paper).
Note (2): Computed with the following quadratic ephemeris,
Min.I=HJD2452984.2611(16)+1.23781061(2)*E+5.88(6)*10-11*E2
(Equation (2) in the paper).
Note (3): τ=T0+A*[((1-e2)/(1+ecosν))sin(ν+ω)+esinω],
where A=a12/c is the semi-amplitude (Equation (3) in the paper).
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref [1/58] Reference number
4- 22 A19 --- BibCode Bibliographic code
24- 40 A17 --- Aut Author's name
42- 85 A44 --- Com Comments
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 05-Dec-2014