J/ApJ/836/64 Luminous variable stars in M31 & M33. IV. (Humphreys+, 2017)
Luminous and variable stars in M31 and M33.
IV. Luminous blue variables, candidate LBVs, B[e] supergiants, and
the warm hypergiants: how to tell them apart.
Humphreys R.M., Gordon M.S., Martin J.C., Weis K., Hahn D.
<Astrophys. J., 836, 64-64 (2017)>
=2017ApJ...836...64H 2017ApJ...836...64H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Stars, giant ; Photometry, UBVRI ;
Photometry, infrared ; Galaxies, nearby ; Spectroscopy
Keywords: galaxies: individual: (M31, M33); stars: massive; supergiants
Abstract:
In this series of papers we have presented the results of a
spectroscopic survey of luminous stars in the nearby spirals M31 and
M33. Here, we present spectroscopy of 132 additional stars. Most have
emission-line spectra, including luminous blue variables (LBVs) and
candidate LBVs, Fe II emission line stars, the B[e] supergiants, and
the warm hypergiants. Many of these objects are spectroscopically
similar and are often confused with each other. We examine their
similarities and differences and propose the following guidelines that
can be used to help distinguish these stars in future work. (1) The
B[e] supergiants have emission lines of [OI] and [FeII] in their
spectra. Most of the spectroscopically confirmed sgB[e] stars also
have warm circumstellar dust in their spectral energy distributions
(SEDs). (2) Confirmed LBVs do not have the [OI] emission lines in
their spectra. Some LBVs have [FeII] emission lines, but not all.
Their SEDs show free-free emission in the near-infrared but no
evidence for warm dust. Their most important and defining
characteristic is the S Dor-type variability. (3) The warm hypergiants
spectroscopically resemble the LBVs in their dense wind state and the
B[e] supergiants. However, they are very dusty. Some have [FeII] and
[OI] emission in their spectra like the sgB[e] stars, but are
distinguished by their A- and F-type absorption-line spectra. In
contrast, the B[e] supergiant spectra have strong continua and few if
any apparent absorption lines. Candidate LBVs should share the
spectral characteristics of the confirmed LBVs with low outflow
velocities and the lack of warm circumstellar dust.
Description:
Our target selection and observations with the MMT/Hectospec and
LBT/MODS1 were described in Paper I (Humphreys+, 2013ApJ...773...46H 2013ApJ...773...46H).
The observations were made in 2010 October with the Hectospec
Multi-Object Spectrograph on the 6.5m MMT on Mount Hopkins (R∼2000).
A few stars of special interest were also observed with the MODS1
spectrograph on the Large Binocular Telescope (LBT) during
commissioning in 2011 September, and in 2012 October and November, and
2013 January (R∼2000).
Our subsequent new spectra span 2013 Sep 25 to 2015 Sep 20.
All of the hot stars for which we have new spectra are listed in Table 2.
The visual photometry from Massey+ (2006, J/AJ/131/2478) was
cross-identified with the near- and mid-infrared photometry from 2MASS
(Cutri+ 2003, II/246), the Spitzer surveys of M31 (Mould+ 2008,
J/ApJ/687/230) and M33 (McQuinn+ 2007, J/ApJ/664/850; Thompson+ 2009,
J/ApJ/705/1364), and WISE (Wright+ 2010AJ....140.1868W 2010AJ....140.1868W - see also
II/311); see table 4.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 175 153 Luminous stars and variables in M31 and M33:
new spectra 2013-2015
table4.dat 125 144 Multi-wavelength photometry
sp_2010/* . 168 M31 & M33 2010 stellar spectra (individual FITS
files in red (6800Å) and blue (4800Å))
sp_2013/* . 254 M31 & M33 2013 stellar spectra
sp_2014/* . 104 M33 2014 stellar spectra
sp_2015/* . 41 M31 2015 stellar spectra
sp_2017/* . 1 M31 2017 stellar spectra
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See also:
J/AJ/110/2715 : UBV photometry in NGC 6822, M31 and M33 (Massey+ 1995)
J/AJ/115/1016 : M 31B eclipsing binaries and Cepheids (Kaluzny+ 1998)
J/ApJ/505/793 : New WR star in M33 (Massey+, 1998)
J/MNRAS/371/1405 : Variables in M33 (Hartman+, 2006)
J/AJ/131/2478 : M31 and M33 UBVRI photometry (Massey+, 2006)
J/AJ/133/2393 : UBVRI phot. in 7 Local Group dwarfs galaxies (Massey+, 2007)
J/AJ/134/2474 : Hα emission-line stars in 7 dwarfs gal. (Massey+, 2007)
J/ApJ/664/850 : Spitzer observations of stars in M33 (McQuinn+, 2007)
J/ApJ/687/230 : Survey of M31 with Spitzer (Mould+, 2008)
J/MNRAS/395/1409 : Type II-P SN progenitor constraints (Smartt+, 2009)
J/ApJ/705/1364 : MIR catalog of point sources in M33 (Thompson+, 2009)
J/ApJ/733/123 : The Wolf-Rayet content of M33 (NGC 598) (Neugent+, 2011)
J/ApJ/790/48 : Variable stars in M31 & M33. II. LBVs (Humphreys+, 2014)
J/ApJ/795/170 : Sample SNRs for M31 and M33 (Jennings+, 2014)
J/ApJ/825/50 : Variable stars in M31 & M33. III. YSGs & RSGs (Gordon+, 2016)
J/AJ/152/62 : Revised LGGS UBVRI photom. of M31 & M33 stars (Massey+, 2016)
http://etacar.umn.edu/LuminousStars/M31M33/ : M31 & M33 HST Treasury Program
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Gal Galaxy identifier (M31 or M33)
5- 24 A20 --- Star Star identifier
26 A1 --- f_Star [a] Flag on Star (1)
28- 29 I2 h RAh Hour of Right Ascension (J2000)
31- 32 I2 min RAm Minute of Right Ascension (J2000)
34- 38 F5.2 s RAs Second of Right Ascension (J2000)
40 A1 --- DE- [+] Sign of Declination (J2000)
41- 42 I2 deg DEd Degree of Declination (J2000)
44- 45 I2 arcmin DEm Arcminute of Declination (J2000)
47- 50 F4.1 arcsec DEs Arcsecond of Declination (J2000)
52- 56 A5 --- Year Year(s) observed; last two digits
59- 80 A22 --- OType Spectroscopic group
82-175 A94 --- Notes Other identifier(s), notes and/or references
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Note (1):
a = LBT/MODS spectrum, Nov. 2014, see text.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Gal Galaxy identifier (M31 or M33)
5- 24 A20 --- Star Star identifier
26- 30 F5.2 mag Umag [15.3/20]? The Johnson U band magnitude
32- 36 F5.2 mag Bmag [15/22.4] The Johnson B band magnitude
38- 42 F5.2 mag Vmag [14/20.6] The Johnson V band magnitude
44- 48 F5.2 mag Rmag [13.6/20]? The Kron-Cousins R band magnitude
50- 54 F5.2 mag Imag [13.3/19.7] The Kron-Cousins I band magnitude
56- 60 F5.2 mag Jmag [12/17.5]? The 2MASS J band magnitude
62- 66 F5.2 mag Hmag [11.4/17]? The 2MASS H band magnitude
68- 72 F5.2 mag Ksmag [11/16.3]? The 2MASS Ks band magnitude
74- 78 F5.2 mag 3.6mag [10.9/17.6]? Spitzer/IRAC 3.6um band magnitude
80- 84 F5.2 mag 4.5mag [11/17.6]? Spitzer/IRAC 4.5um band magnitude
86- 90 F5.2 mag 5.8mag [11/14.1]? Spitzer/IRAC 5.8um band magnitude
92- 96 F5.2 mag 8mag [7.8/13.4]? Spitzer/IRAC 8.0um band magnitude
98-102 F5.2 mag 3.4mag [10.6/17]? WISE 3.4 micron band magnitude
104-108 F5.2 mag 4.6mag [10.6/16.3]? WISE 4.6 micron band magnitude
110-114 F5.2 mag 12mag [6.9/13.1]? WISE 12 micron band magnitude
116-119 F4.2 mag 22mag [3.9/9.6]? WISE 22 micron band magnitude
121-125 A5 --- Var Varibility flag ("var." (15 occurrences) or
"var.?" (1 occurrence))
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History:
From electronic version of the journal (for tables 2 and 4)
From http://etacar.umn.edu/LuminousStars/M31M33/ (September 2017) for
M31 & M33 spectra
References:
Humphreys et al. Paper I. 2013ApJ...773...46H 2013ApJ...773...46H
Humphreys et al. Paper II. 2014ApJ...790...48H 2014ApJ...790...48H Cat. J/ApJ/790/48
Gordon et al. Paper III. 2016ApJ...825...50G 2016ApJ...825...50G Cat. J/ApJ/825/50
Humphreys et al. Paper IV. 2017ApJ...836...64H 2017ApJ...836...64H This catalog
Humphreys et al. Paper V. 2017ApJ...844...40H 2017ApJ...844...40H Cat. J/ApJ/844/40
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 15-Sep-2017