J/MNRAS/519/4699 Minima times of GV Nor and V881 Sco (Suergit+, 2023)
Apsidal motion and absolute parameters of GV Nor and V881 Sco based
on mid-resolution spectroscopy and TESS photometry.
Suergit D., Zasche P., Hadrava P., Erdem A., Engelbrecht C.A., Marang F.,
Masek M., Stevens D.J.
<Mon. Not. R. Astron. Soc. 519, 4699-4715 (2023)>
=2023MNRAS.519.4699S 2023MNRAS.519.4699S (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Binaries, orbits ; Optical
Keywords: stars: binaries: eclipsing - stars: early type -
stars: fundamental parameters - stars: individual: GV Nor -
stars: individual: V881 Sco
Abstract:
The veracity of stellar evolution models and theoretical internal
structure constants may be subjected to stringent tests by using
physical parameters obtained from spectroscopic and photometric
observations of eclipsing binary systems that exhibit apsidal motion.
Two eclipsing binary stars from the southern hemisphere with no prior
published spectroscopic analyses were selected for this study: GV Nor
and V881 Sco. Spectroscopic observations of these two eccentric binary
systems were made at the South African Astronomical Observatory (SAAO)
in 2018 and 2019, and their mid-resolution spectra were obtained. The
radial velocities were measured using the cross-correlation method as
well as by disentangling the spectra. The rotational broadening of the
disentangled spectra of the components was also determined. The
absolute parameters of these two systems were obtained by analyzing
the SAAO-based spectroscopic data in conjunction with photometric data
from TESS. Apsidal motion parameters for these two eccentric binary
systems were calculated by analyzing eclipse timing variations.
Granada and Padova evolution models indicated ages of 340±35Myr
for GV Nor and 760±15Myr for V881 Sco, in agreement with the
observational results. The theoretical internal structure constants
estimated from the Granada models were compatible with the
observational values within the error limits. However, for both
systems, it was found that their circularization and synchronization
timescales were shorter than their respective evolutionary ages.
Therefore, the fact that the components rotate faster than their
synchronized values and still have rather large eccentric orbits
(e∼0.11) challenges present theories of circularization and spin-orbit
synchronization.
Description:
Spectroscopic observations of GV Nor and V881 Sco were
made with the SpUpNIC (Spectrograph Upgrade: Newly Improved
Cassegrain for details) instrument mounted at the Cassegrain focus of
the 1.9-m telescope at the South African Astronomical Observatory
(SAAO). We selected a grating of the spectrograph which has
1200-lines/mm, a wavelength coverage of 400-525nm, a blaze peak at
510nm, and a resolution of 0.06nm (corresponding to a resolution of
approximately 40km/s in radial velocity and an approximate resolving
power R=8000 at the wavelength of the Hβ line). We used a slit
width of 1.35-arcsec for all spectroscopic observations of these two
eclipsing binary systems and the associated radial velocity (RV)
standards, which were observed contemporaneously. A total of 64 and 94
spectra were obtained for GV Nor and V881 Sco, respectively, across
the 2018 and 2019 observing seasons.
Objects:
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RA (2000) DE Designation(s) (Per)
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16 18 41.09 -53 59 42.3 GV Nor = HD 146375 (2.971960855)
16 42 08.08 -33 46 00.5 V881 Sco = HD 150384 (2.491665304)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
etv.dat 74 197 Minima times of GV Nor and V881 Sco
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See also:
J/ApJS/235/41 : Galactic EB stars times of minima (Kim+, 2018)
Byte-by-byte Description of file: etv.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Name of the star
11- 23 F13.5 d HJD Time of minimum
28- 34 F7.5 d e_HJD ? Error on time of minimum
38- 41 A4 --- Type Filter/Method
43- 74 A32 --- Obs Database/Reference
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Acknowledgements:
Petr Zasche, zasche(at)sirrah.troja.mff.cuni.cz
(End) Patricia Vannier [CDS] 06-Jan-2023