J/A+A/452/959 BV light curve of V781 Tau (Kallrath+, 2006)
V781 Tauri: A W Ursae Majoris Binary with Decreasing Period.
Kallrath J., Milone E.F., Breinhorst R.A., Wilson R.E., Schnell A.,
Purgathofer A.
<Astron. Astrophys. 452, 959 (2006)>
=2006A&A...452..959K 2006A&A...452..959K
ADC_Keywords: Binaries, eclipsing ; Photometry, UBV
Keywords: binaries: eclipsing - stars: individual: V781 Tauri
Abstract:
We analyze light curves of the W UMa type eclipsing binary V781 Tauri
from three epochs and radial velocity curves from two epochs
simultaneously, including previously unpublished B and V data.
The overall time span is from 1983 to 2000 and the solution is done
coherently in time (not phase) with five light curves and two sets of
primary and secondary velocity curves. Minor systematic differences
among the individual light curves are not large enough to undermine
the value of a coherent solution that represents 18 years of
observations. Times of minima confirm a period of 0.34491d and the
general solution finds a small period change, dP/P, of
(5.08±04)*10-11 that represents recent behavior. The eclipse
timings cover the last half-century and find dP/P about four times
smaller, corresponding to a period change time scale, P/(dP/dt) of
about 6 million years. The system is over-contact with a filling
factor of 0.205. The solution produces a temperature difference of
about 260K between the components, an inclination of 65.9°, and a
mass ratio M2/M1=2.47. Separate solutions of the several light
curves that incorporate dark spots find parameters that differ little
from curve to curve. Absolute masses, luminosities, radii and the
distance are derived, with luminosities and distance based on star 1
being of type G0V. The orbital angular momentum is compared with those
of other W UMa type binaries and is normal. The star to star mass flow
that one can infer from dP/dt is opposite to that expected from TRO
(Thermal Relaxation Oscillator) theory, but pertains to a time span
that is very short compared to the time scale of TRO oscillations.
Description:
The tables (table10.dat and table11.dat) list the Vienna B and V
curves described in Section 2.2.
Objects:
-----------------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------------
05 50 13.1 +26 57 43 V781 Tau = HD 248087
-----------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table10.dat 21 266 V781 Tau Vienna B differential magnitude
table11.dat 21 1201 V781 Tau Vienna V differential magnitude
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table10.dat table11.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d HJD Helicentric Julian Date
17- 21 F5.3 mag Dmag Vienna B or V differential magnitude
--------------------------------------------------------------------------------
Acknowledgements:
Josef Kallrath, josef.kallrath(at)t-online.de
(End) Josef Kallrath [Bonn, Germany], Patricia Vannier [CDS] 13-Mar-2006