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dc.contributor.authorJenkins, J.S.
dc.contributor.authorMurgas, F.
dc.contributor.authorRojo, P.
dc.contributor.authorJones, H.R.A.
dc.contributor.authorDay-Jones, A.C.
dc.contributor.authorJones, M.I.
dc.contributor.authorClarke, J.R.A.
dc.contributor.authorRuiz, M.
dc.contributor.authorPinfield, D.J.
dc.date.accessioned2011-06-27T14:05:39Z
dc.date.available2011-06-27T14:05:39Z
dc.date.issued2011
dc.identifier.citationJenkins , J S , Murgas , F , Rojo , P , Jones , H R A , Day-Jones , A C , Jones , M I , Clarke , J R A , Ruiz , M & Pinfield , D J 2011 , ' Chromospheric activities and kinematics for solar type dwarfs and subgiants : analysis of the activity distribution and the AVR ' , Astronomy and Astrophysics . https://doi.org/10.1051/0004-6361/201016333
dc.identifier.issn0004-6361
dc.identifier.otherPURE: 170611
dc.identifier.otherPURE UUID: 5ab83332-91d0-4994-9b30-13d0df92d84d
dc.identifier.otherdspace: 2299/6045
dc.identifier.otherScopus: 79957819465
dc.identifier.urihttp://hdl.handle.net/2299/6045
dc.descriptionOriginal article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory
dc.description.abstractAims : In this work we present chromospheric activity indices, kinematics, radial-velocities, and rotational velocities for more than 850 FGK-type dwarfs and subgiant stars in the southern hemisphere and test how best to calibrate and measure S-indices from echelle spectra. Methods. We measured our parameters using the high-resolution and high-S/N FEROS echelle spectra acquired for this purpose. Results. We confirm the bimodal distribution of chromospheric activities for such stars and highlight the role that the more active K-dwarfs play in biasing the number of active stars. We show that the age-activity relationship does appear to continue to ages older than the Sun if we simply compare main sequence stars and subgiant stars with an offset of around 2.5 Gyr between the peaks of both distributions. Also we show evidence of an increased spin-down timescale for cool K dwarfs compared with earlier F and G type stars. We highlight that activities drawn from low-resolution spectra (R < 2500) significantly increase the rms scatter when calibrating onto common systems of measurements like the Mt. Wilson system. Also we show that older and widely used catalogues of activities in the south appear to be offset compared to more recent works at the ∼0.1 dex level in RHK through calibrator drift. In addition, we show how kinematics can be used to preselect inactive stars for future planet search projects. We see the well known trend between projected rotational velocity and activity, however we also find a correlation between kinematic space velocity and chromospheric activity. It appears that after the Vaughan-Preston gap there is a quick step function in the kinematic space motion towards a significantly broader spread in velocities. We speculate on reasons for this correlation and provide some model scenarios to describe the bimodal activity distribution through magnetic saturation, residual low level gas accretion, or accretion by the star of planets or planetesimals. Finally, we provide a new empirical measurement for the disk-heating law, using the latest age-activity relationships to reconstruct the age-velocity distribution for local disk stars. We find a value of 0.337 ± 0.045 for the exponent of this power law (i.e. σtot t0.337), in excellent agreement with those found using isochrone fitting methods and with theoretical disk-heating models.en
dc.language.isoeng
dc.relation.ispartofAstronomy and Astrophysics
dc.rightsOpen
dc.subjectplanetary systems
dc.subjectstars : activity
dc.subjectstars : atmospheres
dc.subjectstars : fundamental parameters
dc.subjectstars : kinematics and dynamics
dc.subjectstars : rotation
dc.titleChromospheric activities and kinematics for solar type dwarfs and subgiants : analysis of the activity distribution and the AVRen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.description.statusPeer reviewed
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dcterms.dateAccepted2011
rioxxterms.versionofrecordhttps://doi.org/10.1051/0004-6361/201016333
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeOpen


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