A Double White-Dwarf Cooling Sequence in ω Centauri
arXiv:1305.0265 · doi:10.1088/2041-8205/769/2/L32
Abstract
We have applied our empirical-PSF-based photometric techniques on a large number of calibration-related WFC3/UVIS UV-B exposures of the core of ω Cen, and found a well-defined split in the right part of the white-dwarf cooling sequence (WDCS). The redder sequence is more populated by a factor of ~2. We can explain the separation of the two sequences and their number ratio in terms of the He-normal and He-rich subpopulations that had been previously identified along the cluster main sequence. The blue WDCS is populated by the evolved stars of the He-normal component (~0.55 Msun CO-core DA objects) while the red WDCS hosts the end-products of the He-rich population (~0.46 Msun objects, ~10% CO-core and ~90% He-core WDs). The He-core WDs correspond to He-rich stars that missed the central He-ignition, and we estimate their fraction by analyzing the population ratios along the cluster horizontal branch.
6 pages, 4 figures, accepted for publication in ApJ Letters. Fixed a typo in the metadata
References in corpus (4)
Cited by in corpus (31)
- Pulsating white dwarfs: new insights
- The State-of-the-Art HST Astro-Photometric Analysis of the core of Centauri. I. The Catalog
- The HST large programme on Centauri - II. internal kinematics
- Ceci n'est pas a globular cluster: the metallicity distribution of the stellar system Terzan 5
- The Hubble Space Telescope UV Legacy Survey of galactic globular clusters. VI. The internal kinematics of the multiple stellar populations in NGC 2808
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- The HST Large Program on Omega Centauri. I. Multiple stellar populations at the bottom of the main sequence probed in NIR-Optical
- Rapidly rotating second-generation progenitors for the blue hook stars of ω Cen
- The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. VII. Implications from the Nearly Universal Nature of Horizontal Branch Discontinuities
- The HST large programme on Centauri -- III. Absolute proper motion
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- First Detection of the White-Dwarf Cooling Sequence of the Galactic Bulge
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- The HST large programme on omega Centauri -- IV. catalogue of two external fields
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- oMEGACat II -- Photometry and proper motions for 1.4 million stars in Omega Centauri and its rotation in the plane of the sky
- The HST Large Programme on NGC 6752. III. Detection of the Peak of the White Dwarf Luminosity Function
- The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIII. ACS/WFC Parallel-Field Catalogues
- Is Terzan 5 the remnant of a building block of the Galactic bulge? Evidence from APOGEE
- Post-common Envelope Evolution of Helium-core White Dwarfs
- Outliers: multicolour photometry guiding the search for evolved binary systems in the globular cluster 47 Tucanae
- Evolution of long-lived globular cluster stars IV. Initial helium content and white-dwarf properties
- Globular Cluster UVIT legacy Survey (GlobUleS) III. Omega Centauri in Far-Ultraviolet
- The Origin of Young Stellar Populations in NGC 1783: Accretion of External Stars
- An excess of luminous white dwarfs in the peculiar Galactic globular cluster NGC 2808