No evidence for activity correlations in the radial velocities of Kapteyn's star
| Autor: | Julien Morin, Matías R. Díaz, Z. M. Berdiñas, Mikko Tuomi, L. F. Sarmiento, Steven S. Vogt, Stephen A. Shectman, Guillem Anglada-Escudé, S. V. Jeffers, E. Gerlach, Pamela Arriagada, Stefan Dreizler, Cristina Rodríguez-López, Paul Butler, C. J. Marvin, James S. Jenkins, Jeffrey D. Crane, Ansgar Reiners, Mathias Zechmeister, Aviv Ofir, Hugh R. A. Jones, P. J. Amado |
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| Přispěvatelé: | Queen Mary University of London (QMUL), University of Hertfordshire, Carnegie Institution of Washington, Queen Mary University London, Universidad de Chile, Weizmann Institute of Science [Rehovot, Israël], Institut für Astrophysik [Göttingen], Georg-August-University [Göttingen], Institut für Planetare Geodäsie [Dresden], Technische Universität Dresden = Dresden University of Technology (TU Dresden), UC Santa Cruz, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Ministerio de Economía y Competitividad (España), German Research Foundation, European Research Council, Fondos de Desarrollo de la Astronomía Nacional (Chile) |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Rotation period
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] Stars: individual (Kapteyn's star) FOS: Physical sciences Astrophysics Star (graph theory) 01 natural sciences symbols.namesake Planet 0103 physical sciences techniques: radial velocities data analysis [Methods] 010303 astronomy & astrophysics Global optimization Instrumentation and Methods for Astrophysics (astro-ph.IM) planetary systems stars: individual: Kapteyn’s star Physics Earth and Planetary Astrophysics (astro-ph.EP) radial velocities [Techniques] 010308 nuclear & particles physics Astronomy and Astrophysics Orbital period individual (Kapteyn's star) [Stars] methods: data analysis Exoplanet [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM] Radial velocity Planetary systems 13. Climate action Space and Planetary Science symbols Astrophysics::Earth and Planetary Astrophysics Astrophysics - Instrumentation and Methods for Astrophysics Doppler effect Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | The Astrophysical Journal The Astrophysical Journal, American Astronomical Society, 2016, 830 (2), pp.74. ⟨10.3847/0004-637X/830/2/74⟩ Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0004-637X 1538-4357 |
| DOI: | 10.3847/0004-637X/830/2/74⟩ |
| Popis: | Guillem Anglada-Escude et. al. Stellar activity may induce Doppler variability at the level of a few m s which can then be confused by the Doppler signal of an exoplanet orbiting the star. To first order, linear correlations between radial velocity measurements and activity indices have been proposed to account for any such correlation. The likely presence of two super-Earths orbiting Kapteyn's star was reported in Anglada-Escudé et al., but this claim was recently challenged by Robertson et al., who argued for evidence of a rotation period (143 days) at three times the orbital period of one of the proposed planets (Kapteyn's b, P = 48.6 days) and the existence of strong linear correlations between its Doppler signal and activity data. By re-analyzing the data using global statistics and model comparison, we show that such a claim is incorrect given that (1) the choice of a rotation period at 143 days is unjustified, and (2) the presence of linear correlations is not supported by the data. We conclude that the radial velocity signals of Kapteyn's star remain more simply explained by the presence of two super-Earth candidates orbiting it. We note that analysis of time series of activity indices must be executed with the same care as Doppler time series. We also advocate for the use of global optimization procedures and objective arguments, instead of claims based on residual analyses which are prone to biases and incorrect interpretations.© 2016. The American Astronomical Society. All rights reserved.. We acknowledge AYA2014-54348-C3-1-R by MINECO/Spain and FEDER funds/EU (P.J.A., C.R.-L., and Z.M.B.); FPIBES-2011-049647 MINECO/Spain (Z.M.B.). A.R. acknowledges research funding from ERC Starting Grant 279347 and DFG Grant RE1664/9-2. M.Z. is funded through DFG Grant RE 1664/12-1. J.S.J. acknowledges funding by Fondecyt through grant 1161218 and partial support from CATA-Basal (PB06, Conicyt). |
| Databáze: | OpenAIRE |
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