2007A&A...476..881K


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.06CEST20:25:25

2007A&A...476..881K - Astronomy and Astrophysics, volume 476, 881-891 (2007/12-3)

Study of FK Comae Berenices. V. Spot evolution and detection of surface differential rotation.

KORHONEN H., BERDYUGINA S.V., HACKMAN T., ILYIN I.V., STRASSMEIER K.G. and TUOMINEN I.

Abstract (from CDS):

We investigate the spot evolution and the surface differential rotation of the single late-type giant FK Com. A total of 18 new surface temperature maps of FK Com are calculated with the Doppler imaging technique for the years 1993-2003. Photometric observations from 2002-2004 are also given. The new and previously published spectroscopic and photometric observations are used to study the spot locations and lifetimes, and to estimate the value of the surface differential rotation. The phases of the active regions determined from the Doppler images follow closely the active longitudes determined earlier from the long-term photometric observations. One active longitude can remain active for several years, but the exact spot configuration within the active longitude changes on much shorter time scales, indicating that the spot lifetime is months instead of years. There are periods during which the spot configuration changes even within days. Measurements using spot latitudes from the Doppler images and spot rotation periods from the photometric observations yield a surface differential rotation law of Ω=(151.30°/day±0.09°/day)-(1.78°/day ±0.12°/day)sin2ψ and the relative differential rotation coefficient α=0.012±0.002 for FK Comae.

Abstract Copyright:

Journal keyword(s): stars: activity - stars: late-type - stars: starspots - stars: individual: FK Comae Berenices

VizieR on-line data: <Available at CDS (J/A+A/476/881): table2a.dat table2b.dat table2c.dat>

Simbad objects: 2

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Number of rows : 2

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 V* FK Com Ro* 13 30 46.7993742986 +24 13 57.786184235   9.04 8.245   7.204 G4III 346 1
2 HD 199178 Ro* 20 53 53.6522297846 +44 23 11.078229740   7.98 7.24     G5III-IV 199 1

    Equat.    Gal    SGal    Ecl

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2020.07.06-20:25:25

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