J/A+A/372/85 Detected sources at 12µm in 47 Tuc (Ramdani+, 2001)
Evolution of the dust mass loss with luminosity along the giant branch of the
globular cluster 47 Tuc.
Ramdani A., Jorissen A.
<Astron. Astrophys. 372, 85 (2001)>
=2001A&A...372...85R 2001A&A...372...85R
ADC_Keywords: Clusters, globular ; Infrared sources ; Magnitudes ;
Photometry, infrared ; Stars, giant
Keywords: globular clusters: 47 Tuc - stars: AGB and post-AGB -
circumstellar matter - stars: mass loss - infrared: stars
Abstract:
The present paper investigates the properties of the dust mass loss in
stars populating the giant branch of the globular cluster 47 Tuc, by
combining ISOCAM and DENIS data. Raster maps of 5 fields covering
areas ranging from 4x4 to 15x15arcmin2 at different distances from
the center of the cluster have been obtained with ISOCAM at 11.5µm
(LW10 filter). The covered fields include most of the red variables
known in this cluster. A detection threshold of about 0.2 mJy is
achieved, allowing us to detect giant stars at 11.5µm all the way
down to the horizontal branch. No dust-enshrouded asymptotic giant
branch stars have been found in the observed fields, contrary to the
situation encountered in LMC/SMC globular clusters with larger turnoff
masses. The color index [12]-[2] (based on the ISO 11.5µm flux and
on the DENIS KS magnitude) is used as a diagnostic of dust emission
(and hence dust mass loss). Its evolution with luminosity along the
giant branch reveals that dust mass loss is only present in V3 (the
only cluster Mira variable observed in the present study) and in V18,
a star presenting intermittent variability. This conclusion confirms
the importance of stellar pulsations in the dust formation and ensuing
mass loss.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 54 236 Star positions (from Simbad)
table3.dat 64 247 List of sources detected at 12 microns, in order
of increasing V magnitude
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See also:
B/denis : The DENIS database (Epchtein+, 1999)
V/97 : Updated 3rd Cat Variable Stars in Globular Clusters (Clement+ 1997)
J/A+AS/93/293 : Astrometry of globular clusters (47 Tuc) (Tucholke 1992)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Source name
10- 11 I2 h RAh ? Right ascension (J2000)
13- 14 I2 min RAm ? Right ascension (J2000)
16- 19 F4.1 s RAs ? Right ascension (J2000)
21 A1 --- DE- Declination sign (J2000)
22- 23 I2 deg DEd ? Declination (J2000)
25- 26 I2 arcmin DEm ? Declination (J2000)
28- 29 I2 arcsec DEs ? Declination (J2000)
33- 57 A25 ---- SName Simbad name
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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 --- Name Name of the source (1)
9- 11 A3 --- VName Variable name (2)
13- 17 F5.2 mag Vmag ? V magnitude (3)
19- 23 F5.2 mag Ksmag ? DENIS Ks magnitude (or K when K < 6.5) (4)
25- 28 F4.2 mag V-Ks ? V-Ks color index
30- 34 F5.2 mag 12um ISOCAM magnitude at 12µm (filter LW-10) (5)
36- 40 F5.3 --- F12/F2 ? Flux density ratio at 12 and 2 microns (6)
42- 46 F5.3 --- e_F12/F2 ? Uncertainty on F12/F2 (from F12 only)
48- 49 A2 --- Field Field number
51- 63 A13 --- Remark Remark about non-membership
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Note (1): Source name:
NNNN: Lee (1977A&AS...27..381L 1977A&AS...27..381L, Cl* NGC 104 Lee NNNN)
x-NNN: Chun & Freeman (1978AJ.....83..376C 1978AJ.....83..376C, Cl* NGC 104 CHUN X NNN)
tucNNNN: Tucholke (1992, Cat. J/A+AS/93/293, Cl* NGC 104 TUC NNNN)
X13: [HJV94] 13 (Hasinger et al., 1994A&A...288..466H 1994A&A...288..466H)
Note (2): Variable name: from Sawyer-Hogg (1973, Cat. V/97)
VN = Cl* NGC 104 SAW VN, Sawyer-Hogg (1973, Cat. V/97)
VNN = Cl* NGC 104 SAW NN, Sawyer-Hogg (1973, Cat. V/97)
RNN = Cl* NGC 104 R NN, Feast & Thackeray (1960MNRAS.120..463F 1960MNRAS.120..463F)
LR5 = Cl* NGC 104 SAW 28
Note (3): V magnitude from Lee (1977A&AS...27..381L 1977A&AS...27..381L) or
Chun & Freeman (1978AJ.....83..376C 1978AJ.....83..376C)
Note (4): DENIS K_s magnitude, (except for V3 (d-502), where K is taken from
Frogel et al., 1981ApJ...246..842F 1981ApJ...246..842F)
Note (5): Magnitude at 12 microns [12], derived from the flux in Jy (F12)
using the relation [12] = -2.5 log F12/28.3.
Note (6): F12/F2 ratio, with F2(Jy) = 665x10-0.4Ks.
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Acknowledgements: Alain Jorissen
(End) Alain Jorissen [IAA-ULB], Patricia Bauer [CDS] 29-Mar-2001