Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades

Publication: Research - peer-reviewJournal article


  • T. R. White
  • B. J. S. Pope
    B. J. S. PopeOxford University, Oxford, UK.
  • V. Antoci
  • P. I. Papics
    P. I. PapicsKU Leuven
  • C. Aerts
    C. AertsRadboud University Nijmegen
  • D. R. Gies
    D. R. GiesGeorgia State Univ, Georgia State University, University System of Georgia, Dept Phys & Astron
  • K. Gordon
    K. GordonGeorgia State Univ, Georgia State University, University System of Georgia, Dept Phys & Astron
  • D. Huber
    D. HuberSETI Inst
  • G. H. Schaefer
    G. H. SchaeferGeorgia State Univ, Georgia State University, University System of Georgia, Dept Phys & Astron
  • S. Aigrain
    S. AigrainOxford University, Oxford, UK.
  • S. Albrecht
  • T. Barclay
    T. BarclayBay Area Environm Res Inst
  • G. Barentsen
    G. BarentsenBay Area Environm Res Inst
  • P. G. Beck
    P. G. BeckCNRSLaboratoire AIM, CEA/DSM – CNRS – Univ. Paris Diderot – IRFU/SAp, Centre de SaclayUniv Paris Diderot, CEA, University of Paris Diderot - Paris VII, Universite Sorbonne Paris Cite-USPC (COMUE), Centre National de la Recherche Scientifique (CNRS), Lab AIM, CEA, DRF,CNRS,IRFU,SAp,Ctr SaclayUniv Paris Diderot, PRES University Sorbonne Paris Cite, University of Paris Diderot - Paris VIICEAUniv Paris, Universite Sorbonne Paris Cite-USPC (COMUE), University of Paris Diderot - Paris VII, Lab Interuniv Syst AtmospherUniv Paris 11, Universite Paris Saclay (ComUE), University of Paris Sud - Paris XI, Inst Astrophys SpatialeCNRS Centre National de la Recherche Scientifique
  • T. R. Bedding
    T. R. BeddingSydney University, Sydney
  • M. Fredslund Andersen
  • F. Grundahl
  • S. B. Howell
    S. B. HowellNASA Ames Research Center
  • M. J. Ireland
    M. J. IrelandRSPAS, Australian National University
  • S. J. Murphy
  • M. B. Nielsen
    M. B. NielsenMax Planck Inst Sonnensyst Forsch, Max Planck SocietyMax Planck Inst Halbleiterlabor, Max Planck SocietyNew York Univ Abu Dhabi, Ctr Space Sci, NYUAD InstSpace Sci Inst, Ctr Extrasolar Planetary Syst
  • V. Silva Aguirre
  • P. G. Tuthill
    P. G. TuthillSydney University, Sydney

The most powerful tests of stellar models come from the brightest stars in the sky, for which complementary techniques, such as astrometry, asteroseismology, spectroscopy and interferometry, can be combined. The K2 mission is providing a unique opportunity to obtain high-precision photometric time series for bright stars along the ecliptic. However, bright targets require a large number of pixels to capture the entirety of the stellar flux, and CCD saturation, as well as restrictions on data storage and bandwidth, limit the number and brightness of stars that can be observed. To overcome this, we have developed a new photometric technique, which we call halo photometry, to observe very bright stars using a limited number of pixels. Halo photometry is simple, fast and does not require extensive pixel allocation, and will allow us to use K2 and other photometric missions, such as TESS, to observe very bright stars for asteroseismology and to search for transiting exoplanets. We apply this method to the seven brightest stars in the Pleiades open cluster. Each star exhibits variability; six of the stars show what are most likely slowly pulsating B-star pulsations, with amplitudes ranging from 20 to 2000 ppm. For the star Maia, we demonstrate the utility of combining K2 photometry with spectroscopy and interferometry to show that it is not a 'Maia variable', and to establish that its variability is caused by rotational modulation of a large chemical spot on a 10 d time-scale.

Original languageEnglish
JournalRoyal Astronomical Society. Monthly Notices
Issue number3
Pages (from-to)2882-2901
Number of pages20
StatePublished - Nov 2017


  • asteroseismology, techniques: photometric, stars: early type, stars: variables: general, open clusters and associations: individual: Pleiades, B-TYPE STARS, ICCD SPECKLE OBSERVATIONS, CHEMICALLY PECULIAR STARS, PALOMAR TESTBED INTERFEROMETER, PIXEL-LEVEL DECORRELATION, SPACE-BASED PHOTOMETRY, DETECTS G-MODES, ORDER G-MODES, V-SIN-I, BINARY STARS

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