J/MNRAS/476/114 Stellar properties of Kron 3 stars (Hollyhead+, 2018)
Kron 3: a fourth intermediate age cluster in the SMC with evidence of multiple
populations.
Hollyhead K., Lardo C., Kacharov N., Bastian N., Hilker M., Rejkuba M.,
Koch A., Grebel E.K., Georgiev I.
<Mon. Not. R. Astron. Soc., 476, 114-121 (2018)>
=2018MNRAS.476..114H 2018MNRAS.476..114H (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Associations, stellar ; Stars, giant ;
Effective temperatures ; Abundances
Keywords: Magellanic Clouds - galaxies: star clusters: individual: Kron 3
Abstract:
We present the results of a spectroscopic study of the intermediate
age (~=6.5Gyr) massive cluster Kron 3 in the Small Magellanic
Cloud. We measure CN and CH band strengths (at ~=3839 and 4300Å,
respectively) using VLT FORS2 spectra of 16 cluster members and find a
sub-population of five stars enriched in nitrogen. We conclude that
this is evidence for multiple populations in Kron 3, the fourth
intermediate age cluster, after Lindsay 1, NGC 416 and NGC 339 (ages
6-8Gyr), to display this phenomenon originally thought to be a unique
characteristic of old globular clusters. At ~=6.5Gyr this is one of
the youngest clusters with multiple populations, indicating that the
mechanism responsible for their onset must operate until a redshift of
at least 0.75, much later than the peak of globular cluster formation
at redshift ∼3.
Description:
FORS2 spectroscopy of 35 RGB stars in the intermediate age massive
cluster Kron 3 in the SMC have yielded 16 member stars after a
conservative membership selection process. We were able to derive CN
and CH index measurements and C and N abundances for 16 stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 132 35 *Stellar properties for all 35 stars in our
programme
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Note on table1.dat: Stars that were found to be non-members using the criteria
specified in Section 3 are indicated. The faintest stars 220, 285, and 791 are
excluded from our analysis due either to their low S/N and the presence of
artefacts/defects within the molecular spectra.
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star Star identification number
6- 13 F8.6 deg RAdeg Right ascension (J2000)
15- 23 F9.5 deg DEdeg Declination (J2000)
25- 29 F5.2 mag Vmag V magnitude
31- 34 I4 K Teff ?=- Effective temperature
36- 37 I2 K e_Teff ?=- rms uncertainty on Teff
39- 41 F3.1 [cm/s2] logg ?=- Surface gravity
43- 45 F3.1 [cm/s2] e_logg ?=- rms uncertainty on logg
47- 51 F5.2 [-] [C/Fe] ?=- Abundance [C/Fe]
53- 56 F4.2 [-] e_[C/Fe] ?=- rms uncertainty on [C/Fe]
58- 62 F5.2 [-] [N/Fe] ?=- Abundance [N/Fe]
64- 67 F4.2 [-] e_[N/Fe] ?=- rms uncertainty on [N/Fe]
69- 74 F6.3 mag CN ?=- CN index
76- 80 F5.3 mag e_CN ?=- rms uncertainty on CN
82- 87 F6.3 mag CH ?=- CH index
89- 93 F5.3 mag e_CH ?=- rms uncertainty on CH
95-100 F6.3 mag Ca(HK) ?=- Ca(HK) index
102-107 F6.3 mag e_Ca(HK) ?=- rms uncertainty on Ca(HK)
109-114 F6.3 mag Fe ?=- Fe index
116-120 F5.3 mag e_Fe ?=- rms uncertainty on Fe
121-125 F5.1 km/s RV Radial velocity
127-132 A6 --- Notes Notes
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Apr-2021