J/A+A/402/745 Radial velocities of ER Vul (Duemmler+, 2003)
The radial velocities and physical parameters of ER Vul.
Duemmler R., Doucet C., Formanek F., Ilyin I., Tuominen I.
<Astron. Astrophys. 402, 745 (2003)>
=2003A&A...402..745D 2003A&A...402..745D
ADC_Keywords: Binaries, spectroscopic ; Radial velocities
Keywords: stars: individual: ER Vul - binaries: spectroscopic -
binaries: eclipsing - stars: late-type - techniques: radial velocities
Abstract:
ER Vul is an eclipsing binary consisting of two solar type stars in a
very close orbit with a period of 0.7d. Accordingly, the two stars
rotate very fast, leading to a blending of many spectral features at
all phases. Therefore, measuring the radial velocity curve without
systematic errors is not trivial. Here, we use a two-dimensional
cross-correlation method applied to 137 high quality spectra,
collected over 3 years, in order to obtain the radial velocity curve
and determine the orbital and some physical parameters of the system
from it. Primarily, we improve the binary period to
0.69809458d±0.00000014d, and find that the two amplitudes are
slightly smaller than those measured by others, while the mass ratio
is still similar. While at least the primary almost fills its Roche
lobe, the system is still detached, i.e. not yet a fully fledged W
UMa-system. The behaviour of the CaII IRT line at 8662Å confirms
that the secondary is the more active component, and that the
chromospheric emission is not symmetrically distributed over the
surfaces of either star.
Description:
The observations consist of 130 echelle spectra obtained with the
high-resolution echelle spectrograph SOFIN (Tuominen et al., 1999,
in Astrophysics with the NOT, ed. H. Karttunen, & V. Piirola, Univ.
Turku, Finland, 47; Ilyin, 2000, Ph.D. Thesis, University of Oulu,
Finland) mounted at the 2.56m Nordic Optical Telescope (NOT) in La
Palma, Spain. These spectra were obtained with the medium resolution
camera (R∼70000), consisting of typically 17 orders of about 50Å
length. Additionally, 7 spectra from the Coude spectrograph at the
2m-RCC-telescope at the National Astronomical Observatory at Rozhen,
Bulgaria, are available. They are centred around 6430Å and have a
length of about 60Å. The spectra cover the time interval June 1993
August 1996.
The table contains the radial velocities for both stars in the ER Vul
system measured with a two-dimensional cross-correlation using the
spun-up solar spectrum as a template for each star. The radial
velocities RV1 and RV2 are weighted averages of the values measured in
up to 5 orders; their errors are the mean errors of the averages. RVCa
is the radial velocity of the Ca II infrared-triplet line at 8662Å.
Errors of -999.999km/s indicate missing measurements.
Objects:
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RA (2000) DE Designation(s)
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21 02 25.9 +27 48 26 ER Vul = HD 200391
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 85 137 The measured radial velocities and their errors
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See also:
J/AN/323/31 : UBVR light curves of ER Vul and RT And (Ekmekci+, 2002)
J/A+A/415/289 : UBVRI light curves of ER Vul (Harmanec+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD Heliocentric Julian date of mid-exposure
15- 22 F8.3 km/s RV1 Radial velocity of the primary
24- 31 F8.3 km/s e_RV1 Standard deviation of RV1
33- 40 F8.3 km/s RV2 Radial velocity of the secondary
42- 49 F8.3 km/s e_RV2 Standard deviation of RV2
51- 58 F8.3 km/s RVCa1 ?=0.000 Radial velocity of the Ca II
line 8662Å for the primary
60- 67 F8.3 km/s e_RVCa1 ?=-999.999 standard deviation of RVCa1
69- 76 F8.3 km/s RVCa2 ?=0.000 Radial velocity of the Ca II
line 8662Å for the secondary
78- 85 F8.3 km/s e_RVCa2 ?=-999.999 standard deviation of RVCa2
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Acknowledgements: Ilya Ilyin
(End) Patricia Bauer [CDS] 22-Apr-2003