J/AJ/161/292 BVRI photometry of pre-W UMA binary V642 Virginis (Samec+, 2021)
BVRcIc observations, third-body orbital study, and analysis of the UV
Leo-type, pre-W UMA binary V642 Virginis.
Samec R.G., Chamberlain H., Caton D., Wolf M., Zasche P., Kucakova H.,
Hornoch K., Morgan S., Faulkner D.R.
<Astron. J., 161, 292-292 (2021)>
=2021AJ....161..292S 2021AJ....161..292S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple; Photometry, UBVRI
Keywords: Eclipsing binary stars; Detached binary stars
RS Canum Venaticorum variable stars
Abstract:
V642Vir is a polar spotted, well-detached, UV Leo-type, low-mass,
pre-WUMa (T1∼4250K, ∼K6V) eclipsing binary. It was observed in 2020
April, May, and June at the Dark Sky Observatory in North Carolina,
USA with the 0.81m reflector of Appalachian State University. A total
of 88 timings were used in our 22-year period study which included 12
Transiting Exoplanet Survey Satellite (TESS) timings. The O-C plots
show a low-amplitude oscillation of residuals that points to the
existence of an orbiting third body, a dwarf of minimum mass,
0.15M☉ in an eccentric orbit (e=0.41), with an orbital period of
20.07yr. The odd light curves of V642 Virginis indicate that it has
polar spots similar to UV Leo and the recently published V1023Per. Its
present large polar spot region indicates that it must have a strong
magnetic field and that it is synchronously rotating. The BVRcIc
simultaneous Wilson-Devinney Program solution gives a detached binary
(primary and secondary components are underfilling their respective
Roche Lobes, with 76% and 78% fill outs respectively). The cool spot
region models near the pole of the primary component (centered at
10° colatitude) and is angled toward the secondary component. Its
large radius (68°) and T-fact (Tspot/Tsurface=0.69) also
attest to the conclusion of the strength of the magnetic field. The
small ΔT in the components (∼318K) and mass ratio near unity
(0.9542±0.0005) show that the stars are similar in spectral type
(secondary ∼K9V). The inclination is high, ∼86.87±0.04°, yet
there is no time of constant light due to the two stars essentially
equal radii.
Description:
Our 2020 Johnson-Cousins BVRcIc light curves were taken on 2020 April
16, 17; May 23, 24; and June 7 at the Dark Sky Observatory in North
Carolina, USA, with the 0.81m reflector of Appalachian State
University at Philips Gap, North Carolina, USA, with standard B,V,Rc ,
and Ic filters.
Four times of minimum light were determined from our present
observations, which include two primary eclipses and two secondary
eclipses. In addition, 12 TESS timings were calculated, and four Super
Nova Search Program of Ohio State (ASAS).Since 2008, the system was
also observed during 63 nights at the Ondrejov Observatory, Czech
Republic. The Mayer 0.65m (f/3.6) reflecting telescope with the
G2-3200 CCD camera and photometric R filter was used.
Objects:
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RA (2000) DE Designation(s) (Period)
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13 30 24.90 +13 49 32.0 V642 Vir = V* V642 Vir (P=0.5166526d)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 This file
table1.dat 55 406 Photometric Observations of V642 Vir
table3.dat 74 89 O-C Residuals, Period Study V642 Vir
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See also:
J/AJ/136/1067 : New beta Lyrae and Algol candidates in NSVS (Hoffman+, 2008)
J/ApJ/723/1469 : Flux calibrations and WZ Oph photometry (Wilson+, 2010)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/A+A/578/A136 : Period changes in SuperWASP eclipsing binaries (Lohr+, 2015)
J/AJ/160/175 : BVRcIc light curve eclisping binary V1023 Persei (Samec+, 2020)
http://var2.astro.cz/ocgate/ : Database of times of minima and maxima
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.3 mag DBmag [1.21/2.29]? Differential B-band magnitude
7- 13 F7.4 d HJDB [5/58]? Heliocentric Julian date of B band
observations; HJD-2458950
15- 19 F5.3 mag DVmag [0.79/1.81]? Differential V-band magnitude
21- 27 F7.4 d HJDV [5/58]? Heliocentric Julian date of V band
observations; HJD-2458950
29- 33 F5.3 mag DRmag [0.46/1.43] Differential R-band magnitude
35- 41 F7.4 d HJDR [5/58] Heliocentric Julian date of R band
observations; HJD-2458950
43- 47 F5.3 mag DImag [0.12/0.96]? Differential I-band magnitude
49- 55 F7.4 d HJDI [5/58]? Heliocentric Julian date of I band
observations; HJD-2458950
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d Epoch [51273/59261]? Epoch, Heliocentric Julian Date,
HJD-2400000
12- 18 F7.1 --- Cycle [-2/15458]? Cycle
20- 28 F9.6 --- RLin [-0.008/0.007] Linear Residuals
30- 38 F9.6 --- ROrb [-0.003/0.002] EC Orbit Residuals
40- 42 F3.1 --- WT [0/1]? Weight
44- 50 F7.4 --- RIni [-0.008/0.007]? Initial Residuals
52- 60 F9.6 --- RQuad [-0.003/0.005] Quadratic Residuals
62- 74 A13 --- Ref Reference (1)
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Note (1): References as follows:
OndHKu = Ondrejov Observatory, observer Hana Kuaa
OndPZ = Ondrejov Observatory, observer Petr Zasche
OndKH = Ondrejov Observatory, observer Kamil Hornoch
Ond = Ondrejov Observatory, observer Marek Wolf
OpavaHKu = Silesian University in Opava, northern Moravia,
observer Hana Kuaa
ValMez = Ladislav Smelcer, Valasske Mezirici Observatory
TESS = Transiting Exoplanet Survey Satellite,
Vanderspek, 2019ESS.....433312V
NSVS = Northern Sky Variability Survey
OC Gate = OMC Gateway http://var2.astro.cz/ocgate/;
Zhang = Zhang+, 2019NewA...70....1B 2019NewA...70....1B
ASAS = All-Sky Automated Survey
ASAS-SN = All-Sky Automated Survey for Supernovae
Diethelm 2009 = Diethelm, 2009IBVS.5894....1D 2009IBVS.5894....1D
Diethelm 2011 = Diethelm, 2011IBVS.5992....1D 2011IBVS.5992....1D
Diethelm 2012 = Diethelm, 2012IBVS.6029....1D 2012IBVS.6029....1D
Diethem 2013 = Diethelm, 2013IBVS.6063....1D 2013IBVS.6063....1D
Present Obs. = This work
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History:
From electronic version of the journal
References:
Samec et al. 2020AJ....160..175S 2020AJ....160..175S Cat. J/AJ/160/175
(End) Prepared by [AAS], Coralie Fix [CDS], 10-Aug-2021