J/A+A/547/A109 Parameters of HB stars in ω Cen (Moni Bidin+, 2012)
Spectroscopy of horizontal branch stars in omega Centauri.
Moni Bidin C., Villanova S., Piotto G., Moehler S., Cassisi S., Momany Y.
<Astron. Astrophys. 547, A109 (2012)>
=2012A&A...547A.109M 2012A&A...547A.109M
ADC_Keywords: Clusters, globular ; Stars, horizontal branch ; Stars, subdwarf;
Radial velocities
Keywords: stars: horizontal branch - stars: atmospheres -
stars: fundamental parameters - stars: abundances -
globular clusters: individual: (omega Centauri)
Abstract:
We analyze the reddening, surface helium abundance and spectroscopic
mass of 115 blue horizontal branch (HB) and blue hook (BH) stars in
ω Centauri (NGC5139), spanning the cluster HB from the blue
edge of the instability strip (Teff=8000K) to BH objects with
Teff∼50000K.
Description:
Our observations targeted 115 HB stars in ω Cen, selected from
the optical photometry of Bellini et al. (2009, Cat. J/A+A/493/959).
The data were collected at the Paranal Observatory in service mode,
with the FORS2 spectrograph mounted on the UT1 telescope, in 2006 from
January to April.
The temperatures, gravities, and surface helium abundances were
derived fitting the Balmer and helium lines with synthetic model
spectra. Reddening and mass were estimated from these parameters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 104 115 Spectroscopic parameters of target stars
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See also:
J/AJ/108/1722 : Blue horizontal branch stars (Kinman+ 1994)
J/A+A/493/959 : UBV(RI)cHalpha photometry in omega Cen (Bellini+, 2009)
J/MNRAS/399/195 : Blue & red spectra of ω Cen HB stars (Van Loon+, 2009)
J/AJ/140/1694 : Abundances of non-variable red and blue HB stars (For+, 2010)
J/A+A/526/A136 : Hot HB stars in ω Cen (Moehler+, 2011)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID [75369/236428] Identification number (1)
8- 13 I6 --- BPB ? Sequential number in Bellini's catalog,
Cl* NGC 5139 BPB NNNNNN in Simbad (3) (2)
16- 21 F6.3 mag Vmag [14.715/19.18] V magnitude (3)
24- 29 F6.3 mag U-V U-V color index (3)
32- 37 F6.3 mag B-V B-V color index (3)
40- 44 I5 K Teff [7800/64000] Effective temperature
46- 50 I5 K e_Teff Error on effective temperature
53- 56 F4.2 [cm/s2] logg [2.92/5.89] Surface gravity
59- 62 F4.2 [cm/s2] e_logg Error on surface gravity
65- 69 F5.2 [Sun] log(He/H) [-3.37/1.33] Surface helium abundance
72- 75 F4.2 [Sun] e_log(He/H) Error on surface helium abundance
78- 81 F4.2 Msun Mass [0.12/0.68] Spectroscopic mass
84- 87 F4.2 Msun e_Mass Error on spectroscopic mass
89- 94 F6.3 mag E(B-V) [-0.121/0.402]? Color excess
97- 99 I3 km/s RV [123/308] Radial velocity
102-104 A3 --- Note [M,T ?] Note (4)
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Note (1): From Momany et al. (2003A&A...407..303M 2003A&A...407..303M; catalog not published)
Note (2): Column added by the author, not part of the original table.
Note (3): From Bellini et al. (2009, Cat. J/A+A/493/959) catalog
Note (4): Note as follows:
M = star in common with Moehler et al. (2011, Cat. J/A+A/526/A136)
T = star re-fitted with TLUSTY models
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Acknowledgements:
Christian Moni Bidin, cmbidin(at)astro-udec.cl
History:
* 06-Nov-2012: On-line version
* 20-Nov-2012: Colunm BPB added by the author
(End) Christian Moni Bidin [UdeC, Chile], Patricia Vannier [CDS] 09-Oct-2012