J/ApJ/703/420 Red supergiants in M31 (Massey+, 2009)
Red supergiants in the Andromeda galaxy (M31).
Massey P., Silva D.R., Levesque E.M., Plez B., Olsen K.A.G., Clayton G.C.,
Meynet G., Maeder A.
<Astrophys. J., 703, 420-440 (2009)>
=2009ApJ...703..420M 2009ApJ...703..420M
ADC_Keywords: Stars, supergiant ; Radial velocities ; Photometry, infrared ;
Spectrophotometry ; Magnitudes ; Galaxies, nearby ; Surveys
Keywords: stars: atmospheres - stars: evolution -
stars: fundamental parameters - stars: late-type
Abstract:
Red supergiants (RSGs) are a short-lived stage in the evolution of
moderately massive stars (10-25M☉), and as such their location
in the H-R diagram provides an exacting test of stellar evolutionary
models. Since massive star evolution is strongly affected by the
amount of mass loss a star suffers, and since the mass-loss rates
depend upon metallicity, it is highly desirable to study the physical
properties of these stars in galaxies of various metallicities. Here
we identify a sample of RSGs in M31, the most metal-rich of the Local
Group galaxies. We determine the physical properties of these stars
using both moderate resolution spectroscopy and broadband V-K
photometry. We find that on average the RSGs of our sample are
variable in V by 0.5mag, smaller but comparable to the 0.9mag found
for Magellanic Cloud (MC) RSGs. No such variability is seen at K, also
in accord with what we know of Galactic and MC RSGs.
Description:
437 stars from the LGGS (Local Group Galaxies Survey) catalog of
Massey et al. (2006, Cat. J/AJ/131/2478 and 2007, Cat. J/AJ/133/2393)
met the photometric criteria required (see table 1).
To confirm their membership in M31, we measured radial velocities
using the CaII triplet (8498, 8542, 8662) observed with the Hydra
multi-object fiber spectrograph on the WIYN 3.5m telescope. The
observations were obtained on 2005 September 27, 28, and 30 (see table
2). Our optical spectroscopy was carried out with the 6.5m MMT
telescope on 2.5 nights of 2006 October 26-28 using the Blue Channel
spectrograph.
All of the stars in our sample had broadband optical photometry in the
LGGS, obtained circa 2000-2001, and many of the stars have Ks band
from Two Micron All Sky Survey (2MASS), obtained 1997-2000. For this
paper, the Ks photometry data were obtained on 2006 October 4 UTC at
the Kitt Peak National Observatory Mayall 4m telescope using the
Florida Multi-object Imaging Near-IR Grism Observational Spectrometer
(FLAMINGOS) (see table 3).
For the V-band photometry, we availed ourselves of two nights on the
Lowell Observatory Perkins 1.8m telescope, 2008 November 21 and 22
(see table 4).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 437 Photometrically selected RSG candidates in M31
table2.dat 79 124 New Radial Velocities (RV) of photometrically
selected RSG candidates
table3.dat 61 71 New Ks photometry and comparison with 2MASS PSC
table4.dat 66 65 New V photometry and comparison with LGGS
table5.dat 112 16 Physical properties of stars with spectrophotometry
table6.dat 79 154 Derived bolometric luminosities for RSGs
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/236 : UBVR CCD survey of the Magellanic clouds (Massey+, 2002)
J/ApJ/687/230 : Survey of M31 with Spitzer (Mould+, 2008)
J/AJ/133/2393 : UBVRI phot. in seven Local Group dwarfs galaxies (Massey+,
2007)
J/AJ/131/2478 : M31 and M33 UBVRI photometry (Massey+, 2006)
J/ApJ/501/153 : VRB photometry of red supergiants (Massey 1998)
J/AJ/96/1884 : BVRJHK photometry of M31 red supergiants (Humphreys+ 1988)
J/MNRAS/289/729 : BVRIJHK photometry of red LMC supergiants (Oestreicher+ 1997)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- [MSL2009] Star identification (JHHMMSS.ss+DDMMSS.s) (1)
21- 25 F5.2 mag Vmag LGGS V band magnitude
27- 30 F4.2 mag B-V LGGS (B-V) color index
32- 35 F4.2 mag V-R LGGS (V-R) color index
37- 41 F5.2 mag R-I ? LGGS (R-I) color index
43- 47 F5.2 mag Ksmag ? 2MASS Ks band magnitude
49 I1 --- r_Ksmag ?=0 Reference for Ksmag: 1=2MASS, 2=this work
51- 54 F4.2 mag V-K ? (V-Ks) color index
56 I1 --- r_V-K ?=0 Reference for V-K (2)
58- 63 F6.1 km/s RV ? Radial velocity
65 I1 --- r_RV ?=0 Reference for RVel (1: this work or
2: Massey, 1998, Cat. J/ApJ/501/153)
67 I1 --- Crowd [0/3] Crowding code (3)
69- 77 A9 --- OID Other identification (4)
79- 84 A6 --- SpT MK spectral type
86 I1 --- r_SpT ?=0 Reference for SpT (5)
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Note (1): From Massey et al. 2006 (LGSS; Cat. J/AJ/131/2478).
Note (2): Code reference as follows:
1 = V from LGGS (Cat. J/AJ/131/2478) and Ks from 2MASS (Cat. II/246);
2 = V from LGGS (Cat. J/AJ/131/2478) and Ks from present work;
3 = V and Ks both from present work.
Note (3): Crowding was determined by computing the contamination from
neighbors under 1.2" seeing with a 1.2" slit; the value reported
is the worst fraction in B, V, or R:
0 = <1%;
1 = 1-5%;
2 = 5-10%;
3 = >10%.
Note (4): From Massey 1998, Cat. J/ApJ/501/153 for OB cross-IDs, and
from Humphreys et al. 1988, Cat. J/AJ/96/1884 for R95.
Note (5): Code reference as follows:
1 = present work;
2 = Massey 1998, Cat. J/ApJ/501/153;
3 = Humphreys et al. 1988, Cat. J/AJ/96/1884.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- [MSL2009] Star designation (JHHMMSS.ss+DDMMSS.s)
20 A1 --- f_[MSL2009] [b] b: Crowded
22- 27 F6.1 km/s RV Observed radial velocity
28 A1 --- f_RV [c] Problem on RV (1)
30 I1 --- Nobs Number of observations
32 A1 --- l_Sig Limit flag on Sig
33- 36 F4.1 km/s Sig Standard deviations of RV means
38- 43 F6.3 --- X/R X/R quantity (2)
45- 48 I4 km/s RVrot Radial velocity from rotating models
50- 58 A9 --- OID Previous identification (3)
60- 63 I4 km/s RVp ? Previous observed RV (3)
65- 70 A6 --- SpTp Previous MK spectral type (3)
72- 79 A8 --- SpTn New MK spectral type
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Note (1): Observations made on two different nights of this star differed by
85km/s, although each measurement was well determined.
Note (2): Quantity X/R is defined with X, the distance along the semi-major axis
and R, the radial distance within the plane of M31.
Note (3): From Massey (1998, Cat. J/ApJ/501/153), except for the star R95,
classified as M1-2 I by Humphreys et al. (1988, Cat. J/AJ/96/1884)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- [MSL2009] Star designation (JHHMMSS.ss+DDMMSS.s)
21- 25 F5.2 mag Ksmag FLAMINGOS Ks-band magnitude
27- 30 F4.2 mag e_Ksmag Ksmag standard deviation of the mean
32- 34 I3 --- o_Ksmag Number of frames N used to measure Ks
36- 40 F5.2 mag Ks2M ? 2MASS Johnson Ks-band magnitude
42- 45 F4.2 mag e_Ks2M ? Ks2M uncertainty
47- 51 F5.2 mag DelKs ? ΔKs: Ksmag minus the Ks2M
53- 56 F4.2 mag e_DelKs ? Total uncertainty (the sum of the two errors
added in quadrature)
58- 61 F4.1 --- NSig ? Sigma difference between this work and
2MASS (1)
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Note (1): (Nσ) shows how many sigma different our results were from
the 2MASS values. We can see from this that the 2MASS values always
agree with ours within a few sigma. Of course, we believe that our new
measurements are more accurate due to lower photon noise errors (due
to large telescope aperture and longer effective exposure times) and
better spatial resolution.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- [MSL2009] Star designation (JHHMMSS.ss+DDMMSS.s)
21- 25 F5.2 mag Vmag V-band magnitude
27- 30 F4.2 mag e_Vmag Vmag uncertainty
31 A1 --- f_Vmag [b] b: affected by crowding at the 0.02-0.05mag
level
33- 34 I2 --- o_Vmag Number of observations
36- 40 F5.2 mag Vprev LGGS V-band magnitude
42- 45 F4.2 mag e_Vprev Vprev uncertainty
47- 51 F5.2 mag DelV New Vmag minus the LGGS V-band magnitude
52 A1 --- f_DelV [b] b: affected by crowding at the 0.02-0.05mag
level
54- 57 F4.2 mag e_DelV DelV uncertainty
58 A1 --- feDelV [b] b: affected by crowding at the 0.02-0.05mag
level
60- 65 F6.1 --- NSig Sigma difference between this work and LGGS
66 A1 --- f_NSig [b] b: affected by crowding at the 0.02-0.05mag
level
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- [MSL2009] Star identification (JHHMMSS.ss+DDMMSS.s)
20 A1 --- f_[MSL2009] [e] e: hot companion?
22- 25 A4 --- SpT MK spectral type
27- 31 F5.2 mag Vmag V band magnitude (1)
32 A1 --- f_Vmag [f] f: from LGGS
34- 38 F5.2 mag Ksmag Ks band magnitude (1)
39 A1 --- f_Ksmag [d] d: from 2MASS
41- 44 F4.2 mag AV V-band extinction (2)
45 A1 --- u_AV [:] Uncertainty flag on AV (2)
47- 51 F5.2 mag VMAG Absolute V-band magnitude (MV) (3)
53- 56 I4 K Teff Effective temperature (4)
57 A1 --- u_Teff [:] Uncertainty flag on Teff (4)
59- 62 F4.1 [cm/s2] loggM Model surface gravity
64- 67 F4.1 [cm/s2] loggC Computed surface gravity
69- 72 I4 Rsun R1 Stellar radius from V band (5)
74- 78 F5.2 mag Mbol1 Bolometric magnitude from VMAG
80- 83 I4 Rsun R2 Stellar radius from K band (5)
85- 89 F5.2 mag Mbol2 Bolometric magnitude from KMAG
91- 96 F6.2 mag KMAG Absolute K-band magnitude from (V-K)0
98-101 I4 K Teff2 Effective temperature from (V-K)0
103-106 I4 Rsun R3 Stellar radius from (V-K)0 (5)
108-112 F5.2 mag Mbol Bolometric magnitude from (V-K)0 at a
distance of 0.76Mpc
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Note (1): Contemporaneous with the spectrophotometry, except as noted.
Note (2): Uncertainties are ±0.10mag unless marked ":" (±0.15mag).
Note (3): MV=V0-24.40 where V0=V-AV
Note (4): Uncertainties are ±25K unless marked ":" (±50K).
Note (5): The stellar radius, from the bolometric luminosity as:
R/R☉=(L/L☉)0.5(5770/Teff)2
where we adopt Mbol=4.75 and Teff=5770K for the sun.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Gal Galaxy name (LMC, M31, MW or SMC)
5- 28 A24 --- Name Star identification
30- 36 A7 --- SpT MK spectral type
38- 41 F4.2 mag AV V band extinction
43- 46 I4 K Teff Effective temperature
48- 52 F5.2 mag VMAG Absolute V band magnitude
54- 57 I4 Rsun R1 Radius from V band magnitude
59- 62 F4.2 [Lsun] L1 Bolometric luminosity from V band magnitude
64- 69 F6.2 mag KMAG ? Absolute K band magnitude
71- 74 I4 Rsun R2 ? Radius from K band magnitude
76- 79 F4.2 [Lsun] L2 ? Bolometric luminosity from K band magnitude
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History:
From electronic version of the journal
References:
Levesque et al. Paper I. 2005ApJ...628..973L 2005ApJ...628..973L
Levesque et al. Paper II. 2006ApJ...645.1102L 2006ApJ...645.1102L
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 14-Oct-2011