J/A+A/588/A54ivo://CDS.VizieR/J/A+A/588/A54doi:10.26093/cds/vizier.35880054CDSWeiss W.W.H.-E. FrohlichPigulski A.Popowicz A.Huber D.Kuschnig R.,Moffat A.F.J.Matthews J.M.Saio H.Schwarzenberg-Czerny A.Grant C.C.,Koudelka O.Luftinger T.Rucinski S.M.Wade G.A.Alves J.Guedel M.,Handler G.Mochnacki St.Orleanski P.Pablo B.Pamyatnykh A.,Ramiaramanantsoa T.Rowe J.Whittaker G.Zawistowski T.Zoclonska E.,Zwintz K.2022-05-14T15:19:27Z2016-03-17T08:02:04ZCDS support team

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

cds-question@unistra.frvariable-starsphotometryWe report on an analysis of high-precision, multi-colour photometric observations of the rapidly-oscillating Ap (roAp) star alpha Cir. These observations were obtained with the BRITE-Constellation, which is a coordinated mission of five nanosatellites that collects continuous millimagnitude-precision photometry of dozens of bright stars for up to 180-days at a time in two colours (~Johnson B and R). BRITE stands for BRight Target Explorer. The object Cir is the brightest roAp star and an ideal target for such investigations, facilitating the determination of oscillation frequencies with high resolution. This star is bright enough for complementary interferometry and time-resolved spectroscopy. Four BRITE satellites observed alpha Cir for 146d or 33 rotational cycles. Phasing the photometry according to the 4.4790d rotational period reveals qualitatively different light variations in the two photometric bands. The phased red-band photometry is in good agreement with previously-published WIRE data, showing a light curve symmetric about phase 0.5 with a strong contribution from the first harmonic. The phased blue-band data, in contrast, show an essentially sinusoidal variation. We model both light curves with Bayesian Photometric Imaging, which suggests the presence of two large-scale, photo- metrically bright (relative to the surrounding photosphere) spots. We also examine the high-frequency pulsation spectrum as encoded in the BRITE photometry. Our analysis establishes the stability of the main pulsation frequency over the last ~20-years, confirms the presence of frequency f_7_, which was not detected (or the mode not excited) prior to 2006, and excludes quadrupolar modes for the main pulsation frequency.2016A&A...588A..54Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/588/A54CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/386/2039 : Elemental abundances of {alpha} Cir (Bruntt+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/588/A54https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/588/A54http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/588/A54https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/588/A54https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/588/A54http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/588/A54GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/588/A54/alpcirbProcessed BRITE-Constellation light curve in BLUE filter (central wavelength ~420nm)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian date (HJD-2456000)dtime.epochdoubleindexedmagMagnitudemagphot.magdoublee_magrms uncertainty on magmagstat.error;phot.magdoubleXcenInstrument X position of centerpixpos.cartesian.x;instr.detfloatYcenInstrument Y position of centerpixpos.cartesian.y;instr.detfloatTInstrument temperature (in Celcius degrees)phys.temperature;instrfloatDiffDifference between autocorrelation and averaged correlation with image shifted by 1 pixel in each of four sidesobs.param;arith.diffdoubleSatName of the satellite (1)meta.id;meta.maincharJ/A+A/588/A54/alpcirrProcessed BRITE-Constellation light curve in RED filter (central wavelength ~620nm)XcenInstrument X position of centerpixpos.cartesian.x;instr.detfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian date (HJD-2456000)dtime.epochdoubleindexedmagMagnitudemagphot.magdoublee_magrms uncertainty on magmagstat.error;phot.magdoubleYcenInstrument Y position of centerpixpos.cartesian.y;instr.detfloatTInstrument temperature (in Celcius degrees)phys.temperature;instrfloatDiffDifference between autocorrelation and averaged correlation with image shifted by 1 pixel in each of four sidesobs.param;arith.diffdoubleSatName of the satellite (1)meta.id;meta.mainchar