J/AJ/155/50 WISE photometry of Be stars in young open clusters (Granada+, 2018)
Quiescent and active phases in Be stars: a WISE snapshot of young Galactic open
clusters.
Granada A., Jones C.E., Sigut T.A.A., Semaan T., Georgy C., Meynet G.,
Ekstrom S.
<Astron. J., 155, 50-50 (2018)>
=2018AJ....155...50G 2018AJ....155...50G (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, open ; Stars, Be ; Photometry, infrared ;
Spectral types ; Effective temperatures ; Equivalent widths
Keywords: infrared: stars - open clusters and associations: general -
stars: activity - stars: emission-line, Be
Abstract:
Through the modeling of near-infrared photometry of star-plus disk
systems with the codes BEDISK/BERAY, we successfully describe the
Wide-Field Infrared Survey Explorer (WISE) photometric characteristics
of Be stars in five young open clusters, NGC 663, NGC 869, NGC 884,
NGC 3766, and NGC 4755, broadly studied in the literature. WISE
photometry allows previously known Be stars to be detected and to find
new Be candidates which could be confirmed spectroscopically. The location
of Be stars in the WISE color-magnitude diagram, separates them in two
groups; active (Be stars hosting a developed circumstellar disk) and
quiescent objects (Be stars in a diskless phase), and this way, we can
explore how often stars are observed in these different stages. The
variability observed in most active variable Be stars is compatible
with a disk dissipation phase. We find that 50% of Be stars in the
studied open clusters are in an active phase. We can interpret this as
Be stars having a developed circumstellar disk one-half of the time.
The location of Be stars with a developed disk in the color-magnitude
diagram require mass loss rates in agreement with values recently
reported in the literature. For these objects, we expect to have a
tight relation between the equivalent width of the Hα line and
the mass of the disk, if the inclination is known. Also, near-infrared
photometry of Be stars in stellar clusters has the potential of being
useful to test whether there is a preferential viewing angle.
Description:
In the present article, we use the IR photometry provided by the
AllWISE source catalog (Cutri et al. 2013, Cat. II/328) for a group of
five open clusters with ages between 10 and 30 Myr, well known for
hosting Be stars and which have been extensively studied in the
literature. We explore how these cluster Be stars are distributed in
the WISE color-magnitude diagram (CMD) and investigate whether the
location of Be stars in these plots can provide global information on
the characteristics of the circumstellar disks and activity cycles for
these stars. In order to interpret the observed near-IR characteristics
of Be stars in open clusters, we generate a grid of synthetic WISE
magnitudes and colors for star-plus-disk systems using the beray code
(Sigut 2011IAUS..272..426S 2011IAUS..272..426S).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 53 5 Selected Open Clusters
table2.dat 147 95 95 Be Stars Analyzed in This Work
table3.dat 139 17 Be Candidates and Other Interesting Objects
that Deserve Further Study
table4.dat 60 120 Synthetic Infrared Magnitudes and Colors
Computed for n=2
table5.dat 60 120 Synthetic Infrared Magnitudes and Colors
Computed for n=2.5
table6.dat 60 120 Synthetic Infrared Magnitudes and Colors
Computed for n=3
table7.dat 60 120 Synthetic Infrared Magnitudes and Colors
Computed for n=3.5
table8.dat 60 120 Synthetic Infrared Magnitudes and Colors
Computed for n=4
table9.dat 21 120 Disk Masses
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See also:
III/277 : Halpha emission objects in the southern Milky Way (Wray, 1966)
III/67 : Catalogue of Be stars (Jaschek+, 1982)
III/205 : H-alpha Stars in Northern Milky Way (Kohoutek+ 1997)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
II/328 : AllWISE Data Release (Cutri+ 2013)
J/A+A/335/565 : Be stars variability (Hubert+ 1998)
J/ApJS/116/263 : VI photometry of open clusters (Piatti+ 1998)
J/A+A/369/511 : Open star clusters. III. NGC 4103, 5281, 4755
(Sanner+, 2001)
J/A+A/376/144 : BV(RI)CHα photometry of NGC 663 (Pigulski+, 2001)
J/ApJ/576/880 : CCD UBV photometry of h and χ Per (Slesnick+, 2002)
J/A+A/437/467 : VLT-FLAMES survey of massive stars (Evans+, 2005)
J/ApJ/622/1052 : byHα photometry of NGC 3766 (McSwain+, 2005)
J/ApJS/161/118 : byHα photometry in open clusters (McSwain+, 2005)
J/MNRAS/358/66 : uvbyβ photometry of NGC 663 (Fabregat+, 2005)
J/ApJ/648/580 : Rotational velocities in 19 open clusters (Huang+, 2006)
J/A+A/496/841 : VLT-FLAMES survey of massive stars (Hunter+, 2009)
J/ApJ/700/1216 : Spectroscopy of Be stars in open clusters
(McSwain+, 2009)
J/ApJ/722/605 : A stellar rotation census of B stars (Huang+, 2010)
J/other/BASI/39.517 : Spectroscopy of classical Be stars (Mathew+, 2011)
J/AJ/144/158 : Properties of B and Be stars in h and χ Persei
(Marsh+, 2012)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Cluster Cluster name
10- 11 I2 h RAh Simbad Hour of Right Ascension (J2000)
13- 14 I2 min RAm Simbad Minute of Right Ascension (J2000)
16- 19 F4.1 s RAs Simbad Second of Right Ascension (J2000)
21 A1 --- DE- Simbad Sign of the Declination (J2000)
22- 23 I2 deg DEd Simbad Degree of Declination (J2000)
25- 26 I2 arcmin DEm Simbad Arcminute of Declination (J2000)
28- 29 I2 arcsec DEs Simbad Arcsecond of Declination (J2000)
31- 34 F4.2 [yr] logAge [7.2/7.5] Log of Age (1)
35 A1 --- n_logAge [b] Note on logAge (2)
37- 41 F5.2 mag muO [11.13/11.85] Distance modulus µO (1)
43- 47 F5.3 mag E(B-V) [0.208/0.7] Reddening (1)
49- 52 F4.1 arcmin Rad [10.5/14.4] Radius of cluster (1)
53 A1 --- n_Rad [c] Note on Rad (3)
--------------------------------------------------------------------------------
Note (1): Kharchenko et al. (2013, J/A+A/558/A53) estimate errors for E(B-V),
age, distance, and radius of 7%, 39%, 11%, and 25%, respectively. The error
estimate in distance of 11% corresponds to an error of the absolute distance
modulus of 0.275 mag.
Note (2): Note as follows:
b = This cluster age, which adequately describes the cluster turn-off and
presence of red supergiant stars using SYCLIST, was not taken from
Kharchenko et al. (2013, J/A+A/558/A53).
Note (3): Note as follows:
c = The cluster radii considered for these two clusters correspond to the
angular radius of the central part (R1) by Kharchenko et al.
(2013, J/A+A/558/A53), instead of the angular radius of the cluster (R2).
This is to avoid cluster overlapping.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 21 F10.6 deg DEdeg Declination in decimal degrees (J2000)
23- 27 F5.2 mag W1Mag [-4.69/0.75] WISE W1 (3.4µm) band absolute
magnitude
29- 32 F4.2 mag e_W1Mag [0.02/0.17] Uncertainty in W1Mag
34- 38 F5.2 mag W1-W2 [-0.18/0.36] WISE W1-W2 color index
40- 43 F4.2 mag e_W1-W2 [0.03/0.17] Uncertainty in W1-W2
45- 49 F5.2 mag W2-W3 [-1.15/2.34] WISE W2-W3 color index
51- 54 F4.2 mag e_W2-W3 [0.02/0.44]? Uncertainty in W2-W3
56- 60 F5.2 mag JMag [-3.89/0.85] 2MASS J band absolute magnitude
62- 65 F4.2 mag e_JMag [0.02/0.05] Uncertainty in JMag
67- 71 F5.2 mag HMag [-3.86/0.84] 2MASS H band absolute magnitude
73- 76 F4.2 mag e_HMag [0.02/0.07] Uncertainty in HMag
78- 82 F5.2 mag KsMag [-4.1/0.8] 2MASS Ks band absolute magnitude
84- 87 F4.2 mag e_KsMag [0.02/0.05] Uncertainty in KsMag
89 I1 --- Var [0/3]? WISE variability of the star (1)
91- 94 F4.1 --- SpType [0/10]? Spectral type (0 corresponds to B0,
1 to B1, and so on)
96 I1 --- LClass [1/5]? Luminosity class
98-123 A26 --- Simbad Simbad name
125-129 I5 K Teff [13254/26700]? Effective temperature
131-134 F4.2 [cm/s2] logg [3.23/4.24]? Surface gravity
136-137 I2 --- r_BeClass [1/15] Reference relevant to the Be star
classification (2)
139 A1 --- Note [*] Note (3)
141-145 A5 --- BeClass Be class assigned to the object in this work
(early, mid, or late Be star)
147 A1 --- n_SpType [+] Note on SpType (4)
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Note (1): WISE variability defined as follows:
0 = No variability flag could be assigned;
1 = Stars that are stable;
2 = Stars without a clear variability signature;
3 = Stars that are variable.
Note (2): Reference as follows:
1 = Mathew & Subramaniam (2011, J/other/BASI/39.517);
2 = Pigulski et al. (2001, J/A+A/376/144);
3 = Kohoutek & Wehmeyer (1997, Cat. III/205);
4 = Coyne et al. (1978PVatO...1..257C 1978PVatO...1..257C);
5 = Abad & Garcia (1995RMxAA..31...15A 1995RMxAA..31...15A);
6 = Slesnick et al. (2002, J/ApJ/576/880);
7 = Marsh Boyer et al. (2012, J/AJ/144/158);
8 = Hog et al. (2000, Cat. I/259);
9 = McSwain et al. (2009, J/ApJ/700/1216);
10 = Huang et al. (2010, J/ApJ/722/605);
11 = Slettebak (1985ApJS...59..769S 1985ApJS...59..769S);
12 = Sanner et al. (2001, J/A+A/369/511);
13 = Jaschek & Egret (1982, Cat. III/67);
14 = McSwain & Gies (2005, J/ApJS/161/118);
15 = Wray (1966, Cat. III/277).
Note (3): Note as follows:
* = There is a source within 8 arcsec of the target, for most of them
significantly weaker.
Note (4): Note as follows:
+ = This is the first time an estimate of the spectral type is given for
the star.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Group [CI] Object group (1)
3- 10 A8 --- Cluster Cluster name
12- 13 I2 h RAh Hour of Right Ascension (J2000)
15- 16 I2 min RAm Minute of Right Ascension (J2000)
18- 23 F6.3 s RAs Second of Right Ascension (J2000)
25 A1 --- DE- Sign of the Declination (J2000)
26- 27 I2 deg DEd Degree of Declination (J2000)
29- 30 I2 arcmin DEm Arcminute of Declination (J2000)
32- 36 F5.2 arcsec DEs Arcsecond of Declination (J2000)
38- 43 F6.3 mag W1Mag [-2.63/0.952] WISE W1 (3.4µm) band absolute
magnitude
45- 50 F6.3 mag W1-W2 [-0.18/0.427] WISE W1-W2 color index
52- 56 F5.3 mag W2-W3 [0.451/2.34]? WISE W2-W3 color index
58- 69 A12 --- Simbad Simbad name
71- 72 I2 --- r_Simbad [1/11]? Reference for Simbad (2)
74-108 A35 --- Type Object type
110 A1 --- r_Type [3]? Reference for Type (2)
112-114 I3 km/s Vproj [165/278]? Projected velocity
116-117 I2 --- r_Vproj [4/12]? Reference for Vproj (2)
119-123 I5 K Teff [14210/20566]? Effective temperature
125 I1 --- r_Teff [4/8]? Reference for Teff (2)
127-131 F5.3 [cm/s2] logg [3.944/4.21]? Surface gravity
133 I1 --- r_logg [4/8]? Reference for logg (2)
135-139 A5 --- SpType MK spectral type
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Note (1): Group as follows:
C = Candidate Be;
I = Interesting object with W12<0.05 but large W23.
Note (2): Reference as follows:
1 = Moffat & Vogt (1974VeBoc...2....1M 1974VeBoc...2....1M);
2 = Gushee (1919AJ.....32..117G 1919AJ.....32..117G);
3 = Huang & Gies (2006, J/ApJ/648/580);
4 = Marsh Boyer et al. (2012, J/AJ/144/158);
5 = Huang et al. (2010, J/ApJ/722/605);
6 = Lavdovsky (1961TrPul..73....5L 1961TrPul..73....5L);
7 = McSwain & Gies (2005, J/ApJS/161/118);
8 = McSwain et al. (2009, J/ApJ/700/1216);
9 = Wildey (1964ApJS....8..439W 1964ApJS....8..439W);
10 = Sanner et al. (2001, J/A+A/369/511);
11 = Evans et al. (2005, J/A+A/437/467);
12 = Hunter et al. (2009, J/A+A/496/841).
All data available in SIMBAD astronomical database (Wenger et al.
2000A&AS..143....9W 2000A&AS..143....9W).
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Byte-by-byte Description of file: table[45678].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- SpType [B1 B3 B7] Spectral type
4- 8 F5.1 10-12g/cm3 rho0 [1/100] Density at the base of the disk
ρ0
10- 11 I2 deg i [18/84] Inclination angle
13- 18 F6.3 mag W1mag [-6.557/-0.167] WISE W1 (3.4µm) band
synthetic magnitude
20- 25 F6.3 mag W1-W2 [-0.041/0.49] WISE W1-W2 synthetic color index
27- 32 F6.3 mag W2-W3 [-0.02/1.393] WISE W2-W3 synthetic color index
34- 39 F6.3 mag Jmag [-5.519/4.335] 2MASS J band synthetic
magnitude
41- 46 F6.3 mag Hmag [-5.577/4.413] 2MASS H band synthetic
magnitude
48- 53 F6.3 mag Ksmag [-5.996/4.716] 2MASS Ks band synthetic
magnitude
55- 60 F6.2 0.1nm EWHa [-64.74/42.79] Equivalent width of the
Hα line (Å)
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Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- SpType [B1 B3 B7] Spectral type
4- 6 F3.1 --- n [2/4] The power-law exponent that determines
how the density decreases with distance in
the equatorial plane from the star
8- 12 F5.1 10-12g/cm3 rho0 [1/100] Density at the base of the disk
ρ0
14- 21 E8.3 --- Md [7.28e-13/2.74e-08] Disk mass, in units of
the stellar mass (M*) (1)
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Note (1): The assumed stellar mass for each spectral type is 13.2 M☉ for
spectral type B1, 7.6 M☉ for spectral type B3 and 4.2 M☉ for
spectral type B7, so conversion to solar masses is straightforward.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 27-Sep-2018