Search Publications
Spherical models of star clusters with potential escapers
Varri, Anna Lisa; Heggie, Douglas C.; Gieles, Mark +2 more
An increasing number of observations of the outer regions of globular clusters (GCs) have shown a flattening of the velocity dispersion profile and an extended surface density profile. Formation scenarios of GCs can lead to different explanations of these peculiarities, therefore the dynamics of stars in the outskirts of GCs are an important tool …
K2 Ultracool Dwarfs Survey - V. High superflare rates on rapidly rotating late-M dwarfs
Mullan, D. J.; Burgasser, A. J.; Stassun, K. G. +5 more
We observed strong superflares (defined as flares with energy in excess of 1033 erg) on three late-M dwarfs: 2MASS J08315742+2042213 (hereafter 2M0831+2042; M7 V), 2MASS J08371832+2050349 (hereafter 2M0837+2050; M8 V), and 2MASS J08312608+2244586 (hereafter 2M0831+2244; M9 V). 2M0831+2042 and 2M0837+2050 are members of the young (∼700 M…
Age gradients throughout the Galaxy with long-period variables
Evans, N. W.; Belokurov, V.; Grady, J.
We assemble the largest sample of oxygen-rich (O-rich) Miras and associated long-period variables (LPVs) to date and highlight their importance for age dating the components of the Galaxy. Using data from the Catalina Surveys and the All Sky Automated Survey for Supernovae, we extract a clean sample of ∼2200 O-rich LPVs, stretching from the Galact…
The geometric challenge of testing gravity with wide binaries
El-Badry, Kareem
Wide binaries provide promising laboratories for testing general relativity (GR) in the low-acceleration regime. Recent observational studies have found that the difference in the proper motions and/or radial velocities of the components of nearby wide binaries appear larger than predicted by Kepler's laws, indicating a potential breakdown of GR a…
Helium enrichment in intermediate-age Magellanic Clouds clusters: towards an ubiquity of multiple stellar populations?
Martocchia, S.; Salaris, M.; Bastian, N. +1 more
Intermediate-age star clusters in the Magellanic Clouds harbour signatures of the multiple stellar populations long thought to be restricted to old globular clusters. We compare synthetic horizontal branch models with Hubble Space Telescope photometry of clusters in the Magellanic Clouds, with age between ∼2 and ∼10 Gyr, namely NGC 121, Lindsay 1,…
A new study of the variable star population in the Hercules globular cluster (M13; NGC 6205)
Arellano Ferro, A.; Calderón, J. H.; Lázaro, C. +4 more
We present the results from VI CCD time-series photometry of the globular cluster M13 (NGC 6205). From the Fourier decomposition of the light curves of RRab and RRc stars we found an average metallicity of [Fe/H]zw = -1.58 ± 0.09. The distance to the cluster was estimated as 7.1 ± 0.1 kpc from independent methods related to the variable star famil…
60Fe in core-collapse supernovae and prospects for X-ray and gamma-ray detection in supernova remnants
Safi-Harb, Samar; Fryer, Chris L.; Mumpower, Matthew R. +6 more
We investigate 60Fe in massive stars and core-collapse supernovae focussing on uncertainties that influence its production in 15, 20, and 25 M⊙ stars at solar metallicity. We find that the 60Fe yield is a monotonic increasing function of the uncertain 59Fe(n, γ)60Fe cross-section and that a fa…
WASP-166b: a bloated super-Neptune transiting a V = 9 star
Bouchy, F.; Queloz, D.; Hellier, Coel +21 more
We report the discovery of WASP-166b, a super-Neptune planet with a mass of 0.1 MJup (1.9 MNep) and a bloated radius of 0.63 RJup. It transits a V = 9.36, F9V star in a 5.44-d orbit that is aligned with the stellar rotation axis (sky-projected obliquity angle λ = 3 ± 5 deg). Variations in the radial-velocity measur…
Smoking gun of the dynamical processing of solar-type field binary stars
Liu, Chao
I investigate the binarity properties of field stars using more than 50 000 main-sequence stars with stellar mass from 0.4 to 0.85 M⊙ observed by LAMOST and Gaia in the solar neighbourhood. By adopting a power-law shape for the mass-ratio distribution with a power index of γ, I conduct a hierarchical Bayesian model to derive the binary …
HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field - III. Spectral analysis, updated parameters and new systems
Kambe, E.; Pigulski, A.; Maehara, H. +5 more
We present the latest results of our spectroscopic observations and refined modelling of a sample of detached eclipsing binaries, selected from the Kepler Eclipsing Binary Catalog, that are also double-lined spectroscopic binaries (SB2s). New high-resolution spectra obtained with the HIgh-Dispersion Echelle Spectrograph (HIDES), attached to the 1.…