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Polarization due to rotational distortion in the bright star Regulus
(2018-10-01)
Polarization in stars was first predicted by Chandrasekhar [1] who calculated a substantial linear polarization at the stellar limb for a pure electron-scattering atmosphere. This polarization will average to zero when ...
VISION - Vienna survey in Orion. III. Young stellar objects in Orion A
(2018-09-30)
We extend and refine the existing young stellar object (YSO) catalogs for the Orion A molecular cloud, the closest massive star-forming region to Earth. This updated catalog is driven by the large spatial coverage (18.3 ...
Primeval very low-mass stars and brown dwarfs - III. The halo transitional brown dwarfs
(2018-09-01)
We report the discovery of an esdL3 subdwarf, ULAS J020858.62+020657.0 and a usdL4.5 subdwarf, ULAS J230711.01+014447.1. They were identified as L subdwarfs by optical spectra obtained with the Gran Telescopio Canarias, ...
A focus on L dwarfs with trigonometric parallaxes
(2018-05-14)
We report new parallax measurements for ten L and early T type dwarfs, five of which have no previous published values, using observations over 3 years at the robotic Liverpool Telescope. The resulting parallaxes and proper ...
Searching for Faint Comoving Companions to the α Centauri system in the VVV Survey Infrared Images
(2017-12-21)
The VVV survey has observed the southern disk of the Milky Way in the near infrared, covering 240 deg$^{2}$ in the $ZYJHK_S$ filters. We search the VVV Survey images in a $\sim$19 deg$^{2}$ field around $\alpha$ Centauri, ...
Extreme infrared variables from UKIDSS - II. an end-of-survey catalogue of eruptive YSOs and unusual stars
(2017-12-11)
We present a catalogue of 618 high-amplitude infrared variable stars (1 < ΔK < 5 mag) detected by the two widely separated epochs of 2.2 μm data in the UKIDSS Galactic plane survey, from searches covering ∼1470 deg2. Most ...
In-depth study of moderately young but extremely red, very dusty substellar companion HD206893B
(2017-12-08)
The substellar companion HD206893b has recently been discovered by direct imaging of its disc-bearing host star with the SPHERE instrument. We investigate the atypical properties of the companion, which has the reddest ...
Constraining cosmic scatter in the Galactic halo through a differential analysis of metal-poor stars
(2017-12)
Context. The chemical abundances of metal-poor halo stars are important to understanding key aspects of Galactic formation and evolution. Aims. We aim to constrain Galactic chemical evolution with precise chemical abundances ...
Constraining cosmic scatter in the Galactic halo through a differential analysis of metal-poor stars
(2017-12)
Context. The chemical abundances of metal-poor halo stars are important to understanding key aspects of Galactic formation and evolution. Aims. We aim to constrain Galactic chemical evolution with precise chemical abundances ...
Extinction ratios in the inner Galaxy as revealed by the VVV survey
(2017-11-01)
Interstellar extinction towards the Galactic Center is large and significantly differential. Its reddening and dimming effects in red clump stars in the Galactic Bulge can be exploited to better constrain the extinction ...