Identifying multiple populations in M71 using CN Virtual Observatory Resource

Authors
  1. Gerber J.M.
  2. Friel E.D.
  3. Vesperini E.
  4. Published by
    CDS
Abstract

We have observed their cyanogen CN features at ~3800 and 4120{AA} as well as the CH band at ~4300{AA} for 145 evolved stars in the Galactic globular cluster M71 using the multi-object spectrograph, Hydra, on the Wisconsin-Indiana-Yale- NOAO-3.5 m telescope. We use these measurements to create two {delta}CN indices finding that both distributions are best fit by two populations: a CN-enhanced and CN-normal. We find that 42%{+/-}4% of the red giant branch stars in our sample are CN-enhanced. The percentage of CN-enhanced is 40%{+/-}13% for the asymptotic giant branch and 33%{+/-}9% for the horizontal branch stars (HB stars), which suggests there are no missing second generation stars at these stages of stellar evolution. The two generations also separate in magnitude and color on the HB, which allows us to find the difference in He abundance between the two populations by fitting appropriate zero-age horizontal branches. The broad range of distances from the cluster's center covered by our sample allows us to study the dependence of the ratio of the number of first to second population stars on the distance from the cluster's center, and we find that this ratio does not vary radially and that the two populations are spatially mixed. Finally, we compare our identification of multiple populations with the classification based on the Na-O anti-correlation and the Hubble Space Telescope UV photometry, and we find good agreement with both methods.

Keywords
  1. Globular star clusters
  2. Effective temperature
  3. Absolute magnitude
  4. Radial velocity
  5. Giant stars
  6. Chemical abundances
  7. Horizontal branch stars
  8. Optical astronomy
  9. Spectroscopy
Bibliographic source Bibcode
2020AJ....159...50G
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/159/50
IVOA Identifier IVOID
ivo://CDS.VizieR/J/AJ/159/50
Document Object Identifer DOI
doi:10.26093/cds/vizier.51590050

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/159/50
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/159/50
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/159/50
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
http://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/159/50/table1?
https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/159/50/table1?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/159/50/table1?

History

2020-03-25T13:42:03Z
Resource record created
2020-03-25T13:42:03Z
Created
2022-09-12T06:46:43Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr