Search
Now showing items 121-130 of 182
Retrieval of atmospheric properties of cloudy L dwarfs
(2017-09-01)
We present the first results from applying the spectral inversion technique in the cloudy L dwarf regime. Our new framework provides a flexible approach to modelling cloud opacity which can be built incrementally as the ...
Uncertainties in s-process nucleosynthesis in massive stars determined by Monte Carlo variations
(2017-08-01)
The $s$-process in massive stars produces the weak component of the $s$-process (nuclei up to $A \sim 90$), in amounts that match solar abundances. For heavier isotopes, such as barium, production through neutron capture ...
A Tale of Three Cities : OmegaCAM discovers multiple sequences in the color-magnitude diagram of the Orion Nebula Cluster
(2017-07-27)
As part of the Accretion Discs in H$\alpha$ with OmegaCAM (ADHOC) survey, we imaged in r, i and H-alpha a region of 12x8 square degrees around the Orion Nebula Cluster. Thanks to the high-quality photometry obtained, we ...
The Gaia Ultracool Dwarf Sample. I. Known L and T dwarfs and the first Gaia data release
(2017-07-01)
We identify and investigate known ultracool stars and brown dwarfs that are being observed or indirectly constrained by the Gaia mission. These objects will be the core of the Gaia ultracool dwarf sample composed of all ...
The metal rich abundance pattern - spectroscopic properties and abundances for 107 main-sequence stars
(2017-07-01)
We report results from the high resolution spectral analysis of the 107 metal rich (mostly [Fe/H]$\ge$7.67 dex) target stars from the Calan-Hertfordshire Extrasolar Planet Search program observed with HARPS. Using our ...
Low-resolution near-infrared spectroscopic signatures of unresolved ultracool companions to M dwarfs
(2017-06-01)
We develop a method to identify the spectroscopic signature of unresolved L-dwarf ultracool companions, which compares the spectra of candidates and their associated control stars using spectral ratio differences and ...
2MASS 0213+3648 C: : A wide T3 benchmark companion to an an active, old M dwarf binary
(2017-05-01)
We present the discovery of a 360 AU separation T3 companion to the tight (3.1 AU) M4.5+M6.5 binary 2MASS J02132062+3648506. This companion was identified using Pan-STARRS1 data and, despite its relative proximity to the ...
Sc and neutron-capture abundances in Galactic low- and high-alpha field halo stars
(2017-05-01)
We determine relative abundance ratios for the neutron-capture elements Zr, La, Ce, Nd and Eu for a sample of 27 Galactic dwarf stars with −1.5 < [Fe/H] < −0.8. We also measure the iron-peak element Sc. These stars separate ...
Characterization of the VVV Survey RR Lyrae Population across the Southern Galactic Plane
(2017-03-27)
Deep near-IR images from the VISTA Variables in the Vía Láctea (VVV) Survey were used to search for RR Lyrae stars in the Southern Galactic plane. A sizable sample of 404 RR Lyrae of type ab stars was identified across a ...
Parallaxes and Infrared Photometry of three Y0 dwarfs
(2017-03-24)
We have followed up the three Y0 dwarfs WISEPA J041022.71+150248.5, WISEPA J173835.53+273258.9 and WISEPC J205628.90+145953.3 using the UKIRT/WFCAM telescope/instruments. We find parallaxes that are more consistent and ...