J/A+A/561/A87 FLAMES observations of Terzan 8 (Carretta+, 2014)
Terzan 8: a Sagittarius-flavoured globular cluster.
Carretta E., Bragaglia A., Gratton R.G., D'Orazi V., Lucatello S.,
Sollima A.
<Astron. Astrophys. 561, A87 (2014)>
=2014A&A...561A..87C 2014A&A...561A..87C
ADC_Keywords: Clusters, globular ; Photometry, UBVRI ; Radial velocities
Keywords: stars: abundances - stars: population II -
globular clusters: general - globular clusters: individual: Terzan 8 -
stars: atmospheres
Abstract:
Massive globular clusters (GCs) contain at least two generations of
stars with slightly different ages and clearly distinct light elements
abundances. The Na-O anticorrelation is the best studied chemical
signature of multiple stellar generations. Low-mass clusters appear
instead to be usually chemically homogeneous. We are investigating
low-mass GCs to understand what is the lower mass limit where multiple
populations can form, mainly using the Na and O abundance
distribution. We used VLT/FLAMES spectra of giants in the low-mass,
metal-poor GC Terzan 8, belonging to the Sagittarius dwarf galaxy, to
determine abundances of Fe, O, Na, alpha-, Fe-peak, and
neutron-capture elements in six stars observed with UVES and 14
observed with GIRAFFE. The average metallicity is [Fe/H]=-2.27±0.03
(rms=0.08), based on the six high-resolution UVES spectra. Only one
star, observed with GIRAFFE, shows an enhanced abundance of Na and we
tentatively assign it to the second generation. In this cluster, at
variance with what happens in more massive GCs, the second generation
seems to represent at most a small minority fraction. We discuss the
implications of our findings, comparing Terzan 8 with the other Sgr
dSph GCs, to GCs and field stars in the Large Magellanic Cloud,
Fornax, and in other dwarfs galaxies.
Description:
We give identification, coordinates, V, Ic, K (2mass) magnitude,
heliocentric radial velocity with error for 101 stars in the Galactic
globular cluster Terzan 8, observed with
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 71 101 ID, coordinates, magnitudes, RVs for stars in
Terzan 8
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See also:
J/A+AS/82/71 : Deep photometry of NGC 5694 and Terzan 8 (Ortolani+, 1990)
J/AJ/136/614 : Arp 2 and Ter 8 red giants equivalent widths (Mottini+, 2008)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID [11/3115] Star identification (from
Montegriffo et al. 1998MNRAS.294..315M 1998MNRAS.294..315M)
6- 7 I2 h RAh Right Ascension J2000 (hours)
9- 10 I2 min RAm Right Ascension J2000 (minutes)
12- 16 F5.2 s RAs Right Ascension J2000 (seconds)
18 A1 --- DE- Declination J2000 (sign)
19- 20 I2 deg DEd Declination J2000 (degrees)
22- 23 I2 arcmin DEm Declination J2000 (minutes)
25- 29 F5.2 arcsec DEs Declination J2000 (seconds)
31- 36 F6.3 mag Vmag Johnson V magnitude
38- 43 F6.3 mag Imag Cousins I magnitude
45- 50 F6.3 mag Kmag ? 2MASS K magnitude
52- 58 F7.2 km/s HRV ? Heliocentric radial velocity
60- 63 F4.2 km/s e_HRV ? Error on HRV
65- 71 A7 --- Note Additional information (1)
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Note (1): Additional information as follows:
UVES = the high-res FLAMES-UVES - otherwise, FLAMES-GIRAFFE
NM = non members
HB = horizontal branch stars
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Acknowledgements:
Eugenio Carretta, eugenio.carretta(at)oabo.inaf.it
(End) Patricia Vannier [CDS] 06-Dec-2013