J/A+A/624/A88 V643 Ori differential light curves (Andersen+, 2019)
V643 Orionis: a detached, evolved, post-mass-exchange eclipsing binary.
Andersen J., Torres G., Clausen J.V.
<Astron. Astrophys. 624, A88 (2019)>
=2019A&A...624A..88A 2019A&A...624A..88A (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Photometry, CCD ; Photometry, uvby
Keywords: stars: evolution - stars: interiors - stars: rotation -
binaries: eclipsing
Abstract:
One of the greatest uncertainties in modelling the mass-exchange
phases during the evolution of a binary system is the amount of mass
and angular momentum that has been lost from the system. In order to
constrain this problem, a favourable, evolved and detached real binary
system is valuable as an example of the end result of this process. We
study the 52-day post-mass-exchange eclipsing binary V643 Ori from
complete uvby light curves and high-resolution spectra. V643 Ori is
double-lined and shows total primary eclipses. The orbit is accurately
circular and the rotation of both stars synchronised with the orbit,
but the photometry from a single year (1993) shows signs of weak spot
activity (0.02mag) around the primary eclipse. We determine accurate
masses of 3.3 and 1.9M☉ from the spectroscopic orbit and solve
the four light curves to determine radii of 16 and 21R☉, using
the Wilson-Devinney photometric code. The rotational velocities from
the cross-correlation profiles agree well with those computed from the
known radii and orbital parameters. All observable parameters are thus
very precisely determined, but the masses and radii of V643 Ori are
incompatible with undisturbed post-main-sequence evolution. We have
attempted to simulate the past evolutionary history of V643 Ori under
both conservative and non-conservative Case B mass transfer scenarios.
In the non-conservative case we varied the amounts of mass and angular
momentum loss needed to arrive at the present masses in a circular
52-day orbit, keeping the two stars detached and synchronized as now
observed, but without following the evolution of other stellar
properties in any detail. Multiple possible solutions were found.
Further attempts were made using both the BSE formalism and the binary
MESA code in order to track stellar evolution more closely, and make
use of the measured radii and temperatures as important additional
constraints. Those efforts did not yield satisfactory solutions,
possibly due to limitations in handling mass transfer in evolved stars
such as these. We remain hopeful that future theoreticians can more
fully model the system under realistic conditions.
Description:
Photometric observations of V643 Ori in the uvby system obtained with
the Stromgren Automatic Telescope and its 6-channel photometer, using
a 17" diaphragm. Comparison stars are HD 42131, HD 41873, and
HD 41143. The light curves contain 524 points, excluding those
affected by spots.
Objects:
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RA (2000) DE Designation(s)
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06 07 00.91 -02 54 57.8 V643 Ori = V* V643 Ori
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 39 524 uvby photometry of V643 Ori
listsp.dat 76 44 List of fits spectra
fits/* . 44 Individual fits spectra
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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- 11 F11.5 d HJD Heliocentric Julian day (HJD-2400000)
12- 18 F7.3 mag Dumag Differential u magnitude
19- 25 F7.3 mag Dvmag Differential v magnitude
26- 32 F7.3 mag Dbmag Differential b magnitude
33- 39 F7.3 mag Dymag Differential y magnitude
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Byte-by-byte Description of file: listsp.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Nx Number of pixels along X-axis
6- 28 A23 "datime" Obs.Date Observation date
30- 36 F7.2 0.1nm blambda Lower value of wavelength interval
38- 44 F7.2 0.1nm Blambda Lower value of wavelength interval
46- 54 F9.7 0.1nm dlambda Spectral resolution
56- 57 I2 Kibyte size Size of FITS file
59- 76 A18 --- FileName Name of FITS file, in subdirectory fits
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Acknowledgements:
Guillermo Torres, gtorres(at)cfa.harvard.edu
(End) Patricia Vannier [CDS] 19-Mar-2019