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502Re: [vsx-dis] Re: [AAVSO-DIS] Question About the Variable Types in the Variable StarIndex

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  • Sebasti├ín Otero
    Sep 5, 2010
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      > IAUS 272 on Actives OB stars
      > http://www.shelyak.com/dossier.php?id_dossier=50&lang=2

      The SPB and BCEP descriptions in that webpage are interchanged. The longer
      period stars are the SPB ones.

      You can also add DPV's
      http://arxiv.org/abs/0910.4359v1
      Binary Be stars showing the orbital variability (EA, EB or ELL) superposed
      to a longer term variation (30-40 times longer than the orbital period)
      caused by the periodic formation and dissipation of a disk.

      A couple of YSO (Young Stellar Objects) classes are (and can be defined as):

      EX= EXors or Subfuors, subspecies of the FU class. They are named after EX
      Lupi. They are eruptive T Tauri stars that show brightening episodes of
      several magnitudes in time scales of several months or a few years. They
      possibly represent an intermediate state between normal T Tauri stars and FU
      Ori stars. (Examples: EX Lup, V1118 Ori, V1143 Ori)

      UX= UXors (UX Ori stars). Herbig Ae/Be stars that show irregular variations
      with a wide range of amplitudes from barely detectable to more than 4 mag in
      V. Large-amplitude variability is confined to stars with spectral types
      later than B8. There are two principal components: (1) irregular variations
      on timescales of days around a mean brightness level that changes on a much
      longer timescale (typically years), sometimes in a quasi-cyclic fashion, and
      (2) occasional episodes of deep minima, occurring at irregular intervals but
      more frequently near the low points of the brightness cycles (extracted from
      ref. 0081) (Examples: UX Ori, CQ Tau, BF Ori)

      Cheers,
      Sebastian.
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