J/A+A/520/A52 31 Com radial velocities (Strassmeier+, 2010)
Rotation and magnetic activity of the Hertzsprung-gap giant 31 Comae.
Strassmeier K.G., Granzer T., Kopf M., Weber M., Kueker M., Reegen P.,
Rice J.B., Matthews J.M., Kuschnig R., Rowe J.F., Guenther D.B.,
Moffat A.F.J., Rucinski S.M., Sasselov D., Weiss W.W.
<Astron. Astrophys. 520, A52 (2010)>
=2010A&A...520A..52S 2010A&A...520A..52S
ADC_Keywords: Stars, giant ; Radial velocities
Keywords: stars: activity - stars: atmospheres - stars: individual: 31 Comae -
starspots - stars: late-type - stars: rotation
Abstract:
The single rapidly-rotating G0 giant 31 Comae has been a puzzle
because of the absence of photometric variability despite its strong
chromospheric and coronal emissions. As a Hertzsprung-gap giant, it
is expected to be at the stage of rearranging its moment of inertia,
hence likely also its dynamo action, which could possibly be linked
with its missing photospheric activity.
Our aim is to detect photospheric activity, obtain the rotation
period, and use it for a first Doppler image of the star's surface.
Its morphology could be related to the evolutionary status.
Description:
We carried out high-precision, white-light photometry with the MOST
satellite, ground-based Stroemgren photometry with automated
telescopes, and high-resolution optical echelle spectroscopy with the
new STELLA robotic facility.
Objects:
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RA (2000) DE Designation(s)
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12 51 41.9 +27 32 27 31 Com = HR 4883
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 53 186 Radial velocities
table3.dat 48 91 KPNO radial velocities
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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2- 11 A10 "DD.MM.YYYY" Obs.date Observation date
13- 20 A8 "h:m:s" Obs.time Time of observation (hh:mm:ss)
24- 37 F14.6 d HJD Heliocentric Julian date of observation
40- 45 F6.3 km/s RV Radial velocity
49- 53 F5.3 km/s e_RV rms uncertainty on RV
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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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2- 11 A10 "YYYY/DD/MM" Date UT Date
13- 24 F12.4 d HJD Heliocentric Julian date
27- 30 F4.1 km/s RV Radial velocity
32- 35 F4.1 km/s e_RV rms uncertainty on RV (1)
38- 48 A11 --- RefStar Reference star (2)
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Note (1): From 1994-1995 the error of a single unit-weight velocity was
4.5km/s. In 1996, a CCD with smaller pixels but also smaller
wavelength coverage was used and the uncertainties were accordingly
larger, ∼7km/s. In 1998, the larger wavelength coverage with a bigger
CCD reduced this again to 4.0km/s.
Note (2): The cross-correlation reference stars 16 Vir, δ Aur, HR
3145, α Tau, and β Gem were used with an adopted velocity
of +35.70, +7.61, +70.90, +54.1 and +3.30km/s, respectively.
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Acknowledgements:
Klaus G. Strassmeier, kstrassmeier(at)ip.de
(End) Patricia Vannier [CDS] 05-Aug-2010