J/AJ/135/1117 Spectroscopic study of red giants in M15 (Meszaros+, 2008)
Mass outflow and chromospheric activity of red giant stars in globular clusters.
I. M15.
Meszaros Sz., Dupree A.K., Szentgyorgyi A.
<Astron. J., 135, 1117-1135 (2008)>
=2008AJ....135.1117M 2008AJ....135.1117M
ADC_Keywords: Stars, giant ; Photometry, infrared ; Photometry, UBV ;
Radial velocities ; Spectroscopy ; Clusters, globular
Keywords: globular clusters: general - globular clusters: individual (M15) -
stars: AGB and post-AGB - stars: chromospheres - stars: mass loss
Abstract:
High-resolution spectra of 110 selected red giant stars in the
globular cluster M15 (NGC 7078) were obtained with Hectochelle at the
MMT telescope in 2005 May, 2006 May, and 2006 October. Echelle orders
containing Hα and CaII H&K are used to identify emission and
line asymmetries characterizing motions in the extended atmospheres.
Emission in Hα is detected to a luminosity of
log(L/L☉)=2.36, in this very metal-deficient cluster, comparable
to other studies, suggesting that the appearance of emission wings is
independent of stellar metallicity. The faintest stars showing
Hα emission appear to lie on the asymptotic giant branch (AGB)
in M15. A line-bisector technique for Hα reveals outflowing
velocities in all stars brighter than log(L/L☉)=2.5, and this
outflow velocity increases with stellar luminosity, indicating the
mass outflow increases smoothly with luminosity. Many stars lying low
on the AGB show exceptionally high outflow velocities (up to
10-15km/s) and more velocity variability (up to 6-8km/s) than red
giant branch (RGB) stars of similar apparent magnitude. High
velocities in M15 may be related to the low cluster metallicity. Dusty
stars identified from Spitzer Space Telescope infrared photometry as
AGB stars are confirmed as cluster members by radial velocity
measurements, yet their Hα profiles are similar to those of RGB
stars without dust. If substantial mass loss creates the circumstellar
shell responsible for infrared emission, such mass loss must be
episodic.
Description:
Observations of a total of 110 red giant stars in M15 were made in
2005 May, 2006 May, and 2006 October with Hectochelle on the MMT
(Multiple Mirror Telescope, Mount Hopkins, USA).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 88 110 Photometric data of observed cluster members
table3.dat 43 110 Physical parameters of cluster members
table5.dat 52 110 Radial Velocity of Cluster Members
table7.dat 47 110 Hα bisector velocity of cluster members
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See also:
J/AJ/137/4282 : Red giant stars in clusters. II. M13 and M92 (Meszaros+, 2009)
J/ApJ/602/264 : Proper motions and radial velocities in M15 (Mcnamara+, 2004)
J/AJ/124/3255 : UBV photometry in M15 (van der Marel+, 2002)
J/AJ/119/1268 : CFHT adaptive optics observations of M15 (Gebhardt+, 2000)
J/AJ/119/2274 : JK Photometry of globular clusters M15 + M56 (Ivanov+, 2000)
J/AJ/113/1026 : Fabry-Perot Observations of M15 (Gebhardt+ 1997)
J/A+AS/46/347 : BV photometry of M15 central part (Auriere+, 1981)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Identification number (G1)
9 A1 --- r_ID [def] Reference used (1)
11- 12 I2 h RAh 2MASS Hour of Right Ascension (J2000)
14- 15 I2 min RAm 2MASS Minute of Right Ascension (J2000)
17- 21 F5.2 s RAs 2MASS Second of Right Ascension (J2000)
23 A1 --- DE- Sign of the 2MASS Declination (J2000)
24- 25 I2 deg DEd 2MASS Degree of Declination (J2000)
27- 28 I2 arcmin DEm 2MASS Arcminute of Declination (J2000)
30- 33 F4.1 arcsec DEs 2MASS Arcsecond of Declination (J2000)
35- 39 F5.2 mag Bmag Cudworth, 1976AJ.....81..519C 1976AJ.....81..519C B band magnitude
41 A1 --- r_Bmag [g] Reference used for Bmag (1)
43- 47 F5.2 mag Vmag Cudworth, 1976AJ.....81..519C 1976AJ.....81..519C V band magnitude
49 A1 --- r_Vmag [g] Reference used for Vmag (1)
51- 56 F6.3 mag Jmag 2MASS J band magnitude
58- 63 F6.3 mag Hmag 2MASS H band magnitude
65- 70 F6.3 mag Ksmag 2MASS Ks band magnitude
72- 75 F4.2 mag B-V The (B-V) color index
77- 80 F4.2 mag V-K The (V-K) color index
82- 88 A7 --- Obs Observation code (2)
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Note (1): Reference as follows:
d = Brown (1951ApJ...113..344B 1951ApJ...113..344B);
e = Cudworth (1976AJ.....81..519C 1976AJ.....81..519C);
f = Gebhardt et al. (1997, Cat. J/AJ/113/1026).
g = Data from Auriere & Cordoni (1981, Cat. J/A+AS/46/347).
Note (2): Observation code as follows:
1 = 2005 May 22;
2 = 2006 May 11;
3 = 2006 October 4;
4 = 2006 October 7;
5 = Dusty giants identified by Boyer et al. (2006AJ....132.1415B 2006AJ....132.1415B).
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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- 7 A7 --- ID Identification number (G1)
9- 13 F5.2 mag VMAG Absolute V band magnitude
15- 18 F4.2 mag B-Vi Intrinsic (B-V) color index
20- 24 F5.3 mag V-Ki Intrinsic (V-K) color index
26- 27 I2 % Mm ? Membership probability (1)
29- 32 I4 K Teff Effective temperature
34- 38 F5.3 [solLum] logL Log of the luminosity
40- 43 F4.1 solRad Rad Star radius
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Note (1): From proper motion observations (Cudworth, 1976AJ.....81..519C 1976AJ.....81..519C).
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Identification number (G1)
9- 14 F6.1 km/s RV1 ? Radial velocity obtained 2005 May 22
16- 18 F3.1 km/s e_RV1 ? Uncertainty in RVel1
20- 25 F6.1 km/s RV2 ? Radial velocity obtained 2006 May 11 (3)
27- 29 F3.1 km/s e_RV2 ? Uncertainty in RVel2 (3)
31- 37 F7.2 km/s RV3 ? Radial velocity obtained 2006 Oct. 4
39- 41 F3.1 km/s e_RV3 ? Uncertainty in RVel3
43- 48 F6.1 km/s RV4 ? Radial velocity obtained 2006 Oct. 7 (3)
50- 52 F3.1 km/s e_RV4 ? Uncertainty in RVel4 (3)
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Note (3): Data taken on 2006 May 11 and on 2006 October 7 were corrected
with a velocity offset of +1.9km/s and +0.9km/s, respectively.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Identification number (G1)
9- 14 F6.2 km/s Va1 ? Hα bisector velocity from 2005 May 22
16- 19 F4.2 km/s e_Va1 ? Uncertainty in Va1
21- 25 F5.1 km/s Va2 ? Hα bisector velocity from 2006 May 11
27- 29 F3.1 km/s e_Va2 ? Uncertainty in Va2
31- 34 F4.1 km/s Va3 ? Hα bisector velocity from 2006 Oct. 4
36- 38 F3.1 km/s e_Va3 ? Uncertainty in Va3
40- 43 F4.1 km/s Va4 ? Hα bisector velocity from 2006 Oct. 7
45- 47 F3.1 km/s e_Va4 ? Uncertainty in Va4
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Global Notes:
Note (G1): Kustner (1921VeBon..15....1K 1921VeBon..15....1K) is the identification for the
majority of the stars denoted by K. ID as follows in Simbad:
BNN = Cl* NGC 7078 BRO NN,
CNN = Cl* NGC 7078 CUD NN,
GEB NNN = Cl* NGC 7078 Geb NNN,
KNNNN = NGC 7078 NNNN in Simbad.
History:
From electronic version of the journal
References:
Meszaros et al., Paper II, 2009AJ....137.4282M 2009AJ....137.4282M, Cat. J/AJ/137/4282
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 28-Jun-2010