Super-He-Rich populations in globular clusters

Chul Chung, Young Wook Lee, Suk Jin Yoon, Seok Joo Joo, Sang Il Han

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Recently observations of the color-magnitude diagrams (CMDs) of the massive globular cluster ω Centauri have shown that it has a striking double main sequence (MS). Here we confirm, with the most up-to-date Y2 isochrones, that this special feature can only be reproduced by assuming a large variation (δ Y=0.15) of primordial helium abundance among several distinct populations in this cluster (Fig. 1). We further show that the same helium enhancement required for this special feature on the MS can by itself reproduce the extreme horizontal branch (HB) stars observed in ω Cen (Fig. 1). Similarly, the complex features on the HBs of other globular clusters, such as NGC 2808, NGC 6388 and NGC 6441, are explained by large internal variations of helium abundance (Fig. 2). The presence of super-helium-rich populations in some globular clusters suggests that a third parameter, other than metallicity and age, also influences the CMD morphology of these clusters.

Original languageEnglish
Title of host publicationGlobular Clusters - Guides to Galaxies
Subtitle of host publicationProceedings of the Joint ESO-FONDAP Workshop on Globular Clusters
EditorsTom Richtler, Soren Larsen
Pages29-30
Number of pages2
DOIs
Publication statusPublished - 2009 Jan 1

Publication series

NameESO Astrophysics Symposia
Volume2009
ISSN (Print)1431-2433
ISSN (Electronic)1611-6143

Fingerprint

globular clusters
helium
color-magnitude diagram
horizontal branch stars
metallicity
augmentation

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Physics and Astronomy (miscellaneous)

Cite this

Chung, C., Lee, Y. W., Yoon, S. J., Joo, S. J., & Han, S. I. (2009). Super-He-Rich populations in globular clusters. In T. Richtler, & S. Larsen (Eds.), Globular Clusters - Guides to Galaxies: Proceedings of the Joint ESO-FONDAP Workshop on Globular Clusters (pp. 29-30). (ESO Astrophysics Symposia; Vol. 2009). https://doi.org/10.1007/978-3-540-76961-3_7
Chung, Chul ; Lee, Young Wook ; Yoon, Suk Jin ; Joo, Seok Joo ; Han, Sang Il. / Super-He-Rich populations in globular clusters. Globular Clusters - Guides to Galaxies: Proceedings of the Joint ESO-FONDAP Workshop on Globular Clusters. editor / Tom Richtler ; Soren Larsen. 2009. pp. 29-30 (ESO Astrophysics Symposia).
@inproceedings{b699fea3b6404ff4b146865ed6cbb543,
title = "Super-He-Rich populations in globular clusters",
abstract = "Recently observations of the color-magnitude diagrams (CMDs) of the massive globular cluster ω Centauri have shown that it has a striking double main sequence (MS). Here we confirm, with the most up-to-date Y2 isochrones, that this special feature can only be reproduced by assuming a large variation (δ Y=0.15) of primordial helium abundance among several distinct populations in this cluster (Fig. 1). We further show that the same helium enhancement required for this special feature on the MS can by itself reproduce the extreme horizontal branch (HB) stars observed in ω Cen (Fig. 1). Similarly, the complex features on the HBs of other globular clusters, such as NGC 2808, NGC 6388 and NGC 6441, are explained by large internal variations of helium abundance (Fig. 2). The presence of super-helium-rich populations in some globular clusters suggests that a third parameter, other than metallicity and age, also influences the CMD morphology of these clusters.",
author = "Chul Chung and Lee, {Young Wook} and Yoon, {Suk Jin} and Joo, {Seok Joo} and Han, {Sang Il}",
year = "2009",
month = "1",
day = "1",
doi = "10.1007/978-3-540-76961-3_7",
language = "English",
isbn = "9783540769606",
series = "ESO Astrophysics Symposia",
pages = "29--30",
editor = "Tom Richtler and Soren Larsen",
booktitle = "Globular Clusters - Guides to Galaxies",

}

Chung, C, Lee, YW, Yoon, SJ, Joo, SJ & Han, SI 2009, Super-He-Rich populations in globular clusters. in T Richtler & S Larsen (eds), Globular Clusters - Guides to Galaxies: Proceedings of the Joint ESO-FONDAP Workshop on Globular Clusters. ESO Astrophysics Symposia, vol. 2009, pp. 29-30. https://doi.org/10.1007/978-3-540-76961-3_7

Super-He-Rich populations in globular clusters. / Chung, Chul; Lee, Young Wook; Yoon, Suk Jin; Joo, Seok Joo; Han, Sang Il.

Globular Clusters - Guides to Galaxies: Proceedings of the Joint ESO-FONDAP Workshop on Globular Clusters. ed. / Tom Richtler; Soren Larsen. 2009. p. 29-30 (ESO Astrophysics Symposia; Vol. 2009).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

TY - GEN

T1 - Super-He-Rich populations in globular clusters

AU - Chung, Chul

AU - Lee, Young Wook

AU - Yoon, Suk Jin

AU - Joo, Seok Joo

AU - Han, Sang Il

PY - 2009/1/1

Y1 - 2009/1/1

N2 - Recently observations of the color-magnitude diagrams (CMDs) of the massive globular cluster ω Centauri have shown that it has a striking double main sequence (MS). Here we confirm, with the most up-to-date Y2 isochrones, that this special feature can only be reproduced by assuming a large variation (δ Y=0.15) of primordial helium abundance among several distinct populations in this cluster (Fig. 1). We further show that the same helium enhancement required for this special feature on the MS can by itself reproduce the extreme horizontal branch (HB) stars observed in ω Cen (Fig. 1). Similarly, the complex features on the HBs of other globular clusters, such as NGC 2808, NGC 6388 and NGC 6441, are explained by large internal variations of helium abundance (Fig. 2). The presence of super-helium-rich populations in some globular clusters suggests that a third parameter, other than metallicity and age, also influences the CMD morphology of these clusters.

AB - Recently observations of the color-magnitude diagrams (CMDs) of the massive globular cluster ω Centauri have shown that it has a striking double main sequence (MS). Here we confirm, with the most up-to-date Y2 isochrones, that this special feature can only be reproduced by assuming a large variation (δ Y=0.15) of primordial helium abundance among several distinct populations in this cluster (Fig. 1). We further show that the same helium enhancement required for this special feature on the MS can by itself reproduce the extreme horizontal branch (HB) stars observed in ω Cen (Fig. 1). Similarly, the complex features on the HBs of other globular clusters, such as NGC 2808, NGC 6388 and NGC 6441, are explained by large internal variations of helium abundance (Fig. 2). The presence of super-helium-rich populations in some globular clusters suggests that a third parameter, other than metallicity and age, also influences the CMD morphology of these clusters.

UR - http://www.scopus.com/inward/record.url?scp=57049125113&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=57049125113&partnerID=8YFLogxK

U2 - 10.1007/978-3-540-76961-3_7

DO - 10.1007/978-3-540-76961-3_7

M3 - Conference contribution

AN - SCOPUS:57049125113

SN - 9783540769606

T3 - ESO Astrophysics Symposia

SP - 29

EP - 30

BT - Globular Clusters - Guides to Galaxies

A2 - Richtler, Tom

A2 - Larsen, Soren

ER -

Chung C, Lee YW, Yoon SJ, Joo SJ, Han SI. Super-He-Rich populations in globular clusters. In Richtler T, Larsen S, editors, Globular Clusters - Guides to Galaxies: Proceedings of the Joint ESO-FONDAP Workshop on Globular Clusters. 2009. p. 29-30. (ESO Astrophysics Symposia). https://doi.org/10.1007/978-3-540-76961-3_7