J/AJ/160/104 Ε CrA components radial & orbital velocity (Rucinski, 2020)
Time-sequence spectroscopy of Epsilon CrA: the 518nm Mg I triplet region
analyzed with broadening functions.
Rucinski S.M.
<Astron. J., 160, 104 (2020)>
=2020AJ....160..104R 2020AJ....160..104R
ADC_Keywords: Stars, double and multiple; Spectra, optical; Radial velocities;
Rotational velocities
Keywords: Eclipsing binary stars ; W Ursae Majoris variable stars ;
Spectroscopic binary stars ; Close binary stars ;
Astronomical techniques
Abstract:
High-resolution spectroscopic observations of the W UMa-type binary
ΕCrA obtained as a time-monitoring sequence on four full and
four partial nights within two weeks have been used to derive orbital
elements of the system and discuss the validity of the Lucy model for
description of the radial-velocity data. The observations had more
extensive temporal coverage and better quality than similar
time-sequence observations of the contact binary AW UMa. The two
binaries share several physical properties and show very similar
deviations from the Lucy model: the primary component is a rapidly
rotating star almost unaffected by the presence of the secondary
component, while the latter is embedded in a complex gas flow and
appears to have its own rotation-velocity field, in contradiction to
the model. The spectroscopic mass ratio is found to be larger than the
one derived from the light-curve analysis, as in many other W UMa-type
binaries, but the discrepancy for Ε CrA is relatively minor,
much smaller than for AW UMa. The presence of the complex velocity
flows contradicting the assumption of solid-body rotation suggests a
necessity of modification to the Lucy model, possibly along the lines
outlined by Stepien in his concept of energy transfer between the
binary components.
Description:
Observations of ε CrA were made in the service mode with the
CHIRON spectrograph on theCerro Tololo Inter-American
Observatory/Small and Moderate Aperture Research Telescope System
(CTIO/SMARTS) 1.5m telescope on eight nights between 2018 July 12 and
29. 361 exposures of 450s were taken using the slicer setup, which
provides a spectral resolving power of R=80000. (Spectral region :
506.05-529.20nm)
Objects:
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RA (2000) DE Designation(s) (Period)
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18 58 43.38 -37 06 26.4 Ε CrA = * eps CrA (P=0.59145447)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 28 361 The radial velocities of the primary component of
Ε CrA
table6.dat 15 184 Orbital velocities of the secondary component of
Ε CrA
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/132/161 : NStars project: The southern sample. I. (Gray+, 2006)
J/A+A/450/681 : Companions to close spectroscopic binaries (Tokovinin+, 2006)
J/AJ/131/1702 : Radial velocities for HD 27638B components (Torres+, 2006)
J/AJ/134/2353 : Observations of contact binaries (Rucinski+, 2007)
J/AJ/141/63 : Relative radial velocities of HAT-P-4 & HAT-P-14 (Winn+,2011)
J/AJ/146/70 : Spectroscopy of W UMa-type binary stars (Rucinski+, 2013)
J/AJ/149/49 : Radial velocities of AW UMa (Rucinski+, 2015)
J/ApJ/806/60 : Radial velocities of 70 Vir (HD117176) (Kane+, 2015)
J/MNRAS/457/836 : Eclipsing binaries MgI b and Hα EW (Eaton, 2016)
J/AJ/153/36 : Minima timings & RVs for 3 eclipsing binaries (Zasche+, 2017)
J/A+A/624/A38 : Radial velocities of K2-36 (Damasso+, 2019)
J/MNRAS/484/5362 : White dwarf+M dwarf binaries RVs (Ashley+, 2019)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 7 F7.4 d HJD [0.52/16.9] Heliocentric Julian Date at
mid-exposure; HJD-2458312
9- 14 F6.3 --- Orb [0.76/28.4] Middle exposure time expressed as
fraction of orbital period
16- 20 F5.2 km/s V1 [27.23/98.12] Centroid, rotational velocity fitting
profile
22- 26 F5.1 km/s vsini [140/167] Projected rotational velocity (1)
28- 28 I1 --- Key [0/1] Used (1) or un-used (0) for primary-component
analysis
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Note (1): Projected rotational velocity determined from the upper 65% of profile
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.4 --- Orb [0.76/28.4] Middle exposure time expressed as
fraction of binary orbital period
9- 15 F7.2 km/s Vel [-224/356] Radial velocity, secondary component (1)
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Note (1): Radial velocity, secondary component in km/s, estimated as a
centroid of the secondary profile on the 2D images (see the text).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 22-Oct-2020