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J/AJ/140/14      Variability of luminous stars in LMC        (Szczygiel+, 2010)
Variability of luminous stars in the Large Magellanic Cloud using 10 years of
ASAS data.
    Szczygiel D.M., Stanek K.Z., Bonanos A.Z., Pojmanski G., Pilecki B.,
    Prieto J.L.
   <Astron. J., 140, 14-24 (2010)>
   =2010AJ....140...14S
ADC_Keywords: Magellanic Clouds ; Stars, variable ; Stars, luminous

Keywords: binaries: eclipsing - Magellanic Clouds - stars: massive -
          stars: variables: general

Abstract:
    Motivated by the detection of a recent outburst of the massive
    luminous blue variable LMC-R71, which reached an absolute magnitude
    MV=-9.3mag, we undertook a systematic study of the optical
    variability of 1268 massive stars in the Large Magellanic Cloud, using
    a recent catalog by Bonanos et al. (2009, Cat. J/AJ/138/1003) as the
    input. The ASAS All Star Catalog provided well-sampled light curves of
    these bright stars spanning 10 years. Combining the two catalogs
    resulted in 599 matches, on which we performed a variability search.
    We identified 117 variable stars, 38 of which were not known before,
    despite their brightness and large amplitude of variation. We found 13
    periodic stars that we classify as eclipsing binary (EB) stars, 8 of
    which are newly discovered bright massive EBs composed of OB-type
    stars. The remaining 104 variables are either semi- or non-periodic,
    the majority (85) being red supergiants (RSGs). Most (26) of the newly
    discovered variables in this category are also RSGs with only three B
    and four O stars.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table3.dat       130      117   Parameters of 117 variable stars identified in
                             this Study


See also:
        II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+ 2002-05)
 J/AJ/138/1003 : IR photometry of massive LMC stars (Bonanos+, 2009)


Byte-by-byte Description of file: table3.dat

   Bytes Format Units   Label     Explanations

   1- 15  A15   ---     Name      Star designation (1)
  17- 26  F10.7 deg     RAdeg     Right Ascension in decimal degrees (J2000)
  28- 38  F11.7 deg     DEdeg     Declination in decimal degrees (J2000)
  40- 44  F5.2  mag     Vmag      Mean ASAS V band magnitude
  46- 49  F4.2  mag     Vamp      Amplitude in V band
  51- 55  F5.2  mag     Imag      ? Mean ASAS I band magnitude
  57- 60  F4.2  mag     Iamp      ? Amplitude in I band
  62- 80  A19   ---     SpType    MK spectral type
  82- 86  F5.3  mag     E(V-I)    ? Mean E(V-I) extinction (2)
  88- 92  A5    ---     GCVS      GCVS LMC designation
  94-130  A37   ---     Notes     Neighbor notes (3)

Note (1): Following Bonanos (2009, Cat. J/AJ/138/1003):
  * Breysacher et al. (BAT99; 1999A&AS..137..117B),
  * Sanduleak (Sk; 1970CoTol..89....1S),
  * Brunet et al. (BI; 1975A&AS...21..109B),
  * Lucke (LH; 1972, PhD thesis, Univ. of Washington, CTIO85 in Simbad),
  * Henize (S; 1956ApJS....2..315H, LHA 120-S in Simbad),
  * Parker et al. (P92; 2001, Cat. J/AJ/121/891, PGMW in Simbad),
  * Massey (M02; 2002, Cat. II/236, [M2002] LMC in Simbad).
  [SP77]39-33 is a misprint for [SP77]29-33 (corrected in the table by CDS).
Note (2): Taken from Pejcha & Stanek (2009ApJ...704.1730P).
  0.000 correspond to negative values for the calculated extinction, which is
  the case for 30 out of 101 stars for which the extinction value was available.
Note (3): Approximate brightness and distance of close neighbors, based on DSS
  images. See Section 3.3 for details.


History:
    From electronic version of the journal
(End)                  Greg Schwarz [AAS], Patricia Vannier [CDS]    08-Jun-2012