J/A+A/399/315 sigma2 CrB radial velocities (Strassmeier+, 2003)
Doppler imaging of stellar surface structure.
XIX. The solar-type components of the close binary σ2 Coronae Borealis.
Strassmeier K.G., Rice J.B
<Astron. Astrophys. 399, 315 (2003)>
=2003A&A...399..315S 2003A&A...399..315S
ADC_Keywords: Binaries, spectroscopic ; Radial velocities
Keywords: stars: activity - stars: starspots - stars: imaging -
stars: individual: σ2 CrB - stars: late-type
Abstract:
We present the first Doppler image for both stellar components of the
F9+G0 ZAMS binary σ2 CrB and found evidence for the
coexistence of cool and warm spots on both stars. Cool spots appear
mainly at polar or high latitudes while a confined equatorial warm
belt appears on the trailing hemisphere of each of the two stars with
respect to the orbital motion. We also present an update of the
TempMap imaging code that allows us to solve the stellar surface
temperature distribution on both binary components simultaneously,
including photometric input. Several test reconstructions are
performed to demonstrate its reliability and robustness. Our new
orbital solution results in very precise masses for both components -
good to 0.4% - and confirms the spectral classifications of F9 and G0
for the primary and secondary, respectively. The visual component,
σ1, seems to be G4 rather than G0. All three components are on
or very close to the ZAMS which is also confirmed by the relatively
high lithium abundance of about twenty times the solar abundance.
Description:
High-resolution spectroscopic observations were obtained with the
Gecko Coude spectrograph at the 3.6-m Canada-France-Hawaii telescope
(CFHT) in two observing runs each two nights long in May 17-18, 2000
and May 21-22, 2000. This splitting of nights was mandatory in order
to obtain full phase coverage because the orbital period (and the
rotational periods) is 1.14 days, and thus close to the day-night
cycle.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1a.dat 42 224 σ2 CrB Star 1 radial velocities,
CFHT-Gecko May2000
table1b.dat 42 226 σ2 CrB Star 2 radial velocities,
CFHT-Gecko May2000
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Byte-by-byte Description of file: table1a.dat table1b.dat
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Bytes Format Units Label Explanations
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1- 11 F11.3 d HJD Heliocentric Julian date
14- 18 F5.3 --- Phase Orbital phase according to "Table3" section
21- 25 F5.1 km/s RV Radial velocity in km/s
28- 32 F5.1 km/s O-C ? O-C from the orbital computation
35- 38 A4 --- Obs Observatory name
(CFHT: Canada-France-Hawaii Telescope)
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Table3: Improved orbital element
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Elemenet (unit) Value
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Porb (days) 1.1397912 (adopted)
T0 (HJD) 2451683.4400
γ (km/s) -12.3 ± 0.06
K1 (km/s) 61.34 ± 0.06
K2 (km/s) 62.91 ± 0.08
e 0.0 (adopted)
a1sini (km) 0.96138±0.00093x106
a2sini (km) 0.9861 ±0.0012 x106
a (i=28°) (km) 4.148 x 106
m1(sini)3 (solMass) 0.1147
m2(sini)3 (solMass) 0.1118
mass ratio 0.975 ± 0.002
m1 (i=28°) (solMass) 1.108 ± 0.004
m2 (i=28°) (solMass) 1.108 ± 0.004
RMS for solution (km/s) 0.71
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Acknowledgements: Klaus G. Strassmeier
(End) Patricia Bauer [CDS] 19-Feb-2003