J/A+A/580/A64ivo://CDS.VizieR/J/A+A/580/A64doi:10.26093/cds/vizier.35800064CDSVida K.Korhonen H.Ilyin I.V.Olah K.Andersen M.I.Hackman T.2017-10-02T19:28:28Z2015-08-04T06:51:41ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frvariable-starsspectroscopyWe study the connection between the chromospheric and photospheric behaviour of the active late-type star FK Comae. We use spot temperature modelling, light curve inversion based on narrow- and wide-band photometric measurements, Halpha observations from 1997-2010, and Doppler maps from 2004-2010 to compare the behaviour of chromospheric and photospheric features. Investigating low-resolution H{alpha} spectra we find that the changes in the chromosphere seem to happen mainly on a time scale longer than a few hours, but shorter variations were also observed. According to the Halpha measurements prominences are often found in the chromosphere that reach to more than a stellar radius and are stable for weeks, and which seem to be often, but not every time connected with dark photospheric spots. The rotational modulation of the H{alpha} emission seems to typically be anticorrelated with the light curve, but we did not find convincing evidence of a clear connection in the long-term trends of the Halpha emission and the brightness of the star. In addition, FK Com seems to be in an unusually quiet state in 2009-2010 with very little chromospheric activity and low spot contrast, that might indicate the long-term decrease of activity.2015A&A...580A..64Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/580/A64CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/278/449 : Long-term photometry of FK Com (Jetsu+ 1993)J/A+A/282/L9 : "flip-flop" in FK Com (Jetsu+ 1994)J/A+AS/103/183 : UVBRI photometry of FK Com (Jetsu+ 1994)J/A+A/374/1049 : Photometry of FK Com for 1993-2001 (Korhonen+, 2001)J/A+A/390/179 : Study of FK Comae Berenices. IV. (Korhonen+ 2002)J/A+A/467/229 : UBV photometry of FK Com and HD 199178 (Panov+, 2007)J/A+A/476/881 : Differential photometry of FK Com (Korhonen+, 2007)J/A+A/553/A40 : UBVI light curves of FK Com (Hackman+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/580/A64https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/580/A64http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/580/A64https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/580/A64https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/580/A64http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/580/A64GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/580/A64/spectraList of available spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintInstSimbad column added by the CDSmeta.code;obscharspShow the spectrummeta.ref.urlcharFileNameSpectrum file name in subdirectory spmeta.id;meta.filecharJDJulian date of observationdtime.epochdoublefileDownload the spectrum (2-column table)meta.ref.urlchar