Related papers: Helium-Core White Dwarfs in Globular Clusters

To investigate the dynamical properties of globular clusters, the surface brightness and kinematic data were collected and fitted to a family of lowered isothermal models called LIMEPY models. For 18 studied globular clusters, the amounts…

We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the…

Recent years have witnessed the discovery of many low-mass ($\lesssim 0.45 M_{\odot}$) white dwarf (WD) stars --- expected to harbor He cores--- in the field of the Milky Way and in several galactic globular and open clusters. Recently,…

In this work, we use $N-$body simulations performed on GPU to trace the past 10 Gyr dynamical history of a globular cluster (GC) similar to NGC~6397 in the tidal field of a Milky Way-like galaxy and we compare our simulated GCs with data…

We provide a fine and homogeneous grid of evolutionary sequences for He-core white dwarfs with masses 0.15-0.45 Msun, including the mass range for ELM white dwarfs (<0.20Msun). The grid is appropriate for mass and age determination, and to…

We present VI photometry of the metal-poor inner halo globular clusters NGC6293 and NGC6541 using the planetary camera of the WFPC2 on board HST. Our color-magnitude diagrams of the clusters show well-defined BHB populations, consistent…

White dwarfs (WDs) are the stellar core remnants of low mass stars. They are typically divided into three main composition groups: Oxygen Neon (ONe), Carbon Oxygen (CO) and Helium (He) WDs. The evolution of binary systems can significantly…

(Abridged) We investigate the hypothesis that some fraction of the globular clusters presently observed in the Galactic halo formed in external dwarf galaxies, by means of a detailed comparison between Zinn's "old halo", "young halo", and…

We have obtained high resolution (<1") deep x-ray images of the globular cluster 47Tucanae (NGC 104) with the Chandra X-ray Observatory to study the population of compact binaries in the high stellar density core. A 70 kilosec exposure of…

We present a new time-series VI CCD photometry of the globular cluster NGC 6397, from which we obtained and analysed the light curves of 35 variables carefully identified in the cluster field. We assessed the membership of the variables…

We describe here the reduction methods that we developed to study the faintest red dwarfs and white dwarfs in an outer field of NGC6397, which was observed by \hst for 126 orbits in 2005. The particular challenge of this data set is that…

Spectroscopic observations of binary stars in globular clusters are essential to shed light on the poorly constrained period, eccentricity, and mass ratio distributions and to develop an understanding of the formation of peculiar stellar…

The persistence of planetary systems after their host stars evolve into their post-main sequence phase is poorly constrained by observations. Many young white dwarf systems exhibit infrared excess emission and/or spectral absorption lines…

We present observations of the two closest globular clusters, NGC 6121 and NGC 6397, taken with the NIRISS detector of JWST. The combination of our new JWST data with archival Hubble Space Telescope (HST) images allows us to compute proper…

This is the second of two papers presenting a detailed examination of Fokker-Planck models for the globular cluster NGC 6397 and is concerned with extracting information on the cluster from the models. The models give a current cluster mass…

Hydrogen deficient stars include the cool R CrB variable (RCBs) and hydrogen-deficient carbon (HdCs) giants through extreme helium stars (EHes) to the very hot helium-rich subdwarfs (He-sdO and O(He) stars) and white dwarfs. With surfaces…

White dwarfs with a F, G or K type companion represent the last common ancestor for a plethora of exotic systems throughout the galaxy, though to this point very few of them have been fully characterised in terms of orbital period and…

Numerical simulations of the disruption of a dwarf companion moving in the polar plane of a massive galaxy are presented. The constructed model is compared with observational data on the recently discovered low-surface-brightness stellar…

We present the results of our Hubble Space Telescope far-ultraviolet survey of the blue lurkers (BLs) in M67. We find evidence for two white dwarf companions among the BLs that are indicative of mass transfer from an evolved companion, one…

Globular clusters (GCs) are spheroidal concentrations typically containing of the order of 10^5 to 10^6, predominantly old, stars. Historically, they have been considered as the closest counterparts of the idealized concept of "simple…