J/ApJ/812/12ivo://CDS.VizieR/J/ApJ/812/12doi:10.26093/cds/vizier.18120012CDSEgeland R.Metcalfe T.S.Hall J.C.Henry G.W.2017-06-20T13:16:11Z2016-02-22T13:07:12ZCDS support team

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

cds-question@unistra.frvisible-astronomymedium-band-photometryg-starsA growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial (~2yr) variation, which is superimposed upon the dominant 11 year cycle. A well-characterized stellar sample suggests at least two different relationships between rotation period and cycle period, with some stars exhibiting long and short cycles simultaneously. Within this sample, the solar cycle periods are typical of a more rapidly rotating star, implying that the Sun might be in a transitional state or that it has an unusual evolutionary history. In this work, we present new and archival observations of dual magnetic cycles in the young solar analog HD 30495, a ~1Gyr old G1.5V star with a rotation period near 11 days. This star falls squarely on the relationships established by the broader stellar sample, with short-period variations at ~1.7yr and a long cycle of ~12yr. We measure three individual long-period cycles and find durations ranging from 9.6 to 15.5yr. We find the short-term variability to be intermittent, but present throughout the majority of the time series, though its occurrence and amplitude are uncorrelated with the longer cycle. These essentially solar-like variations occur in a Sun-like star with more rapid rotation, though surface differential rotation measurements leave open the possibility of a solar equivalence.2015ApJ...812...12Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/812/12CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)J/A+A/551/L8 : Chromospheric activity of field stars (Pace, 2013)J/ApJ/763/L26 : SMARTS observations of eps Eridani (Metcalfe+, 2013)J/A+A/531/A8 : Activity indexes and velocities for 890 stars (Jenkins+, 2011)J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)J/A+A/520/A79 : FGK stars chromospheric activity (Martinez-Arnaiz+, 2010)J/AJ/138/312 : Activity of bright solar analogs (Hall+, 2009)J/A+A/483/903 : Mount Wilson index for FGK stars (Buccino+, 2008)J/A+A/469/309 : Chromospheric activity in late-type stars (Cincunegui+, 2007)J/AJ/132/161 : NStars project: The southern sample. I. (Gray+, 2006)J/ApJS/152/261 : Chromospheric Ca II emission in nearby stars (Wright+, 2004)J/A+A/365/545 : Remnant disks around MS stars IR flux (Habing+, 2001)J/ApJ/457/L99 : 25yr CaII-HK obs. of F-K nearby stars (Baliunas+, 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/812/12https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/812/12http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/812/12https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/812/12https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/812/12http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/812/12GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/812/12/table3S-index observations of HD 30495recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD[39787.4/56965.8] Heliocentric Julian Date; HJD-2400000dtime.epochdoubleS[0.24/0.39] The S-index (1)spect.indexdoublee_S[0.0004/0.04] The 1-sigma uncertainty in Sstat.errordoubleInstInstrument used (CPS, HARPS, MWO, SMARTS or SSS)instr.setupcharJ/ApJ/812/12/table4Photometric observations of HD 30495recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD[49239.9/57080.7] Heliocentric Julian Date; HJD-2400000dtime.epochdouble(P-C1)b[-0.5/-0.3] HD30495-HD31414 differential mag in bmagphot.mag;arith.difffloat(P-C1)y[-0.3/-0.1] HD30495-HD31414 differential mag in ymagphot.mag;arith.difffloat(P-C2)b[-0.3/-0.1] HD30495-HD30606 differential mag in bmagphot.mag;arith.difffloat(P-C2)y[-0.3/-0.2] HD30495-HD30606 differential mag in ymagphot.mag;arith.difffloat(C2-C1)b[-0.2/-0.1] HD30606-HD31414 differential mag in bmagphot.mag;arith.difffloat(C2-C1)y[0.04/0.08] HD30606-HD31414 differential mag in ymagphot.mag;arith.difffloat