J/ApJ/810/157 V471 Tau system: RVs and BVRI LCs (Vaccaro+, 2015)
The V471 Tauri system: a multi-data-type probe.
Vaccaro T.R., Wilson R.E., Van Hamme W., Terrell D.
<Astrophys. J., 810, 157 (2015)>
=2015ApJ...810..157V 2015ApJ...810..157V (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Radial velocities ; Photometry, UBVRI
Keywords: binaries: eclipsing; binaries: spectroscopic;
stars: individual: V471 Tau
Abstract:
V471 Tauri, a white dwarf-red dwarf eclipsing binary (EB) in the
Hyades, is well known for stimulating development of common envelope
theory, whereby novae and other cataclysmic variables form from much
wider binaries by catastrophic orbit shrinkage. Our evaluation of a
recent imaging search that reported negative results for a much
postulated third body shows that the object could have escaped
detection or may have actually been seen. The balance of evidence
continues to favor a brown dwarf companion about 12 AU from the EB. A
recently developed algorithm finds unified solutions from three data
types. New radial velocities (RVs) of the red dwarf and BVRcIc light
curves are solved simultaneously along with white dwarf and red dwarf
RVs from the literature, uvby data, the Microvariability and
Oscillations of Stars mission light curve, and 40 years of eclipse
timings. Precision-based weighting is the key to proper information
balance among the various data sets. Timewise variation of modeled
starspots allows unified solution of multiple data eras. Light-curve
amplitudes strongly suggest decreasing spottedness from 1976 to about
1980, followed by approximately constant spot coverage from 1981 to
2005. An explanation is proposed for lack of noticeable variation in
1981 light curves, in terms of competition between spot and tidal
variations. Photometric-spectroscopic distance is estimated. The red
dwarf mass comes out larger than normal for a K2 V star, and even
larger than adopted in several structure and evolution papers. An
identified cause for this result is that much improved red dwarf RV
curves now exist.
Description:
Radial velocities of the red dwarf from our 1998 Kitt Peak National
Observatory (KPNO) observations made with the 0.9m Coude Feed of the
2.1m telescope are in Table 1. Their characteristics (instrument,
integration times, etc.) are in Vaccaro & Wilson (2002ASPC..279..167V 2002ASPC..279..167V).
Our 1998 differential light curves with respect to comparison star
BD+16515, observed at KPNO with the 0.9m Southeastern Association for
Research in Astronomy telescope and described in Vaccaro & Wilson
(2002ASPC..279..167V 2002ASPC..279..167V), are in Table 2.
Objects:
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RA (ICRS) DE Designation(s) (Period)
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03 50 24.97 +17 14 47.4 V471 Tauri = BD+16 516 (P=0.52118338)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 41 126 Red dwarf 1998 radial velocities (RVs)
table2.dat 137 877 B, V, Rc, Ic 1998 light curves (LCs)
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
B/sb9 : 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix+ 2004-2014)
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
J/A+A/559/A43 : Pan-STARRS1 (PS1) observations of the Hyades (Goldman+, 2013)
J/ApJS/187/149 : StarCAT: STIS UV echelle spectra of stars (Ayres, 2010)
J/other/A+ARV/17.251 : Stars observed with Doppler imaging (Strassmeier, 2009)
J/other/IBVS/5802 : Minima and maxima of 735 variables (Hubscher+, 2007)
J/AJ/134/2353 : Observations of contact binaries (Rucinski+, 2007)
J/AJ/131/2986 : Multiplicity of contact binaries (Pribulla+, 2006)
J/A+A/446/785 : Catalogue of eclipsing variables (Malkov+, 2006)
J/AcA/54/207 : Ephemerids of eclipsing binaries (Kreiner, 2004)
J/MNRAS/349/1069 : Chromospherically active binaries (Karatas+, 2004)
J/A+A/381/446 : Astrometric Radial Velocities. III. (Madsen+, 2002)
J/A+A/367/111 : A Hipparcos study of the Hyades cluster (de Bruijne+, 2001)
J/A+A/281/811 : Long-term variations in V471 Tau (Ibanoglu+ 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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2- 14 F13.5 d HJD Heliocentric Julian Date
16- 28 F13.5 d HJED Heliocentric Julian Ephemeris Date
30- 36 F7.2 km/s RV [-122/187] Radial Velocity
38- 41 F4.2 km/s e_RV [1/5] Individual RV standard error
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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- 13 F13.5 d HJD(B) B band Heliocentric Julian Date
15- 27 F13.5 d HJED(B) B band Heliocentric Julian Ephemeris Date (1)
29- 34 F6.3 mag dBmag [-0.5/-0.2] Differential B magnitude (2)
36- 48 F13.5 d HJD(V) V band Heliocentric Julian Date
50- 62 F13.5 d HJED(V) V band Heliocentric Julian Ephemeris Date (1)
64- 69 F6.3 mag dVmag [-0.2/0.02]?=9.999 Differential V magnitude (2)
71- 83 F13.5 d HJD(R) Rc band Heliocentric Julian Date
85- 97 F13.5 d HJED(R) Rc band Heliocentric Julian Ephemeris Date (1)
99-103 F5.3 mag dRmag [0.05/0.2]?=9.999 Differential Rc magnitude (2)
105-117 F13.5 d HJD(I) Ic band Heliocentric Julian Date
119-131 F13.5 d HJED(I) Ic band Heliocentric Julian Ephemeris Date (1)
133-137 F5.3 mag dImag [0.3/0.5]?=9.999 Differential Ic magnitude (2)
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Note (1): Heliocentric Julian Ephemeris Date (HJED) in the Terrestrial Time
(TT) scale.
Note (2): Differential magnitudes are in the sense Variable - Comparison,
with BD+16 515 as the comparison star (B=10.718±0.011,
V=9.433±0.011, RC=8.080.±0.026 and IC=8.246±0.019).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 18-Dec-2015