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Title: The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. III. The Main Sequence's Multiple Populations Galore

Abstract

We take advantage of the exquisite quality of the Hubble Space Telescope 26-filter astro-photometric catalog of the core of ω Cen presented in the first paper of this series and the empirical differential-reddening correction presented in the second paper in order to distill the main sequence into its constituent populations. To this end, we restrict ourselves to the five most useful filters: the magic “trio” of F275W, F336W, and F438W, along with F606W and F814W. We develop a strategy for identifying color systems where different populations stand out most distinctly, then we isolate those populations and examine them in other filters where their subpopulations also come to light. In this way, we have identified at least 15 subpopulations, each of which has a distinctive fiducial curve through our five-dimensional photometric space. We confirm the MSa to be split into two subcomponents, and find that both the bMS and the rMS are split into three subcomponents. Moreover, we have discovered two additional MS groups: the MSd (which has three subcomponents) shares similar properties with the bMS, and the MSe (which has four subcomponents) has properties more similar to those of the rMS. We examine the fiducial curves together and use syntheticmore » spectra to infer relative heavy-element, light-element, and helium abundances for the populations. Our findings show that the stellar populations and star formation history of ω Cen are even more complex than inferred previously. Finally, we provide as a supplement to the original catalog a list that identifies for each star which population it is most likely associated with.« less

Authors:
; ;  [1]; ;  [2]; ;  [3];  [4]
  1. Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States)
  2. Research School of Astronomy and Astrophysics, Australian National University, Mt Stromlo Observatory, via Cotter Rd, Weston, ACT 2611 (Australia)
  3. Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, Padova, I-35122 (Italy)
  4. Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)
Publication Date:
OSTI Identifier:
22663305
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 844; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; CATALOGS; CORRECTIONS; FILTERS; HELIUM; PHOTOMETRY; SPACE; SPECTRA; STARS; TELESCOPES; VISIBLE RADIATION

Citation Formats

Bellini, A., Anderson, J., Van der Marel, R. P., Milone, A. P., Marino, A. F., Piotto, G., Bedin, L. R., and King, I. R., E-mail: bellini@stsci.edu. The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. III. The Main Sequence's Multiple Populations Galore. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA7B7E.
Bellini, A., Anderson, J., Van der Marel, R. P., Milone, A. P., Marino, A. F., Piotto, G., Bedin, L. R., & King, I. R., E-mail: bellini@stsci.edu. The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. III. The Main Sequence's Multiple Populations Galore. United States. doi:10.3847/1538-4357/AA7B7E.
Bellini, A., Anderson, J., Van der Marel, R. P., Milone, A. P., Marino, A. F., Piotto, G., Bedin, L. R., and King, I. R., E-mail: bellini@stsci.edu. Tue . "The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. III. The Main Sequence's Multiple Populations Galore". United States. doi:10.3847/1538-4357/AA7B7E.
@article{osti_22663305,
title = {The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. III. The Main Sequence's Multiple Populations Galore},
author = {Bellini, A. and Anderson, J. and Van der Marel, R. P. and Milone, A. P. and Marino, A. F. and Piotto, G. and Bedin, L. R. and King, I. R., E-mail: bellini@stsci.edu},
abstractNote = {We take advantage of the exquisite quality of the Hubble Space Telescope 26-filter astro-photometric catalog of the core of ω Cen presented in the first paper of this series and the empirical differential-reddening correction presented in the second paper in order to distill the main sequence into its constituent populations. To this end, we restrict ourselves to the five most useful filters: the magic “trio” of F275W, F336W, and F438W, along with F606W and F814W. We develop a strategy for identifying color systems where different populations stand out most distinctly, then we isolate those populations and examine them in other filters where their subpopulations also come to light. In this way, we have identified at least 15 subpopulations, each of which has a distinctive fiducial curve through our five-dimensional photometric space. We confirm the MSa to be split into two subcomponents, and find that both the bMS and the rMS are split into three subcomponents. Moreover, we have discovered two additional MS groups: the MSd (which has three subcomponents) shares similar properties with the bMS, and the MSe (which has four subcomponents) has properties more similar to those of the rMS. We examine the fiducial curves together and use synthetic spectra to infer relative heavy-element, light-element, and helium abundances for the populations. Our findings show that the stellar populations and star formation history of ω Cen are even more complex than inferred previously. Finally, we provide as a supplement to the original catalog a list that identifies for each star which population it is most likely associated with.},
doi = {10.3847/1538-4357/AA7B7E},
journal = {Astrophysical Journal},
number = 2,
volume = 844,
place = {United States},
year = {Tue Aug 01 00:00:00 EDT 2017},
month = {Tue Aug 01 00:00:00 EDT 2017}
}