Search Publications
Toward Understanding the B[e] Phenomenon. VII. AS 386, a Single-lined Binary with a Candidate Black Hole Component
Reichart, D. E.; Miroshnichenko, A. S.; Manset, N. +24 more
We report the results of spectroscopic and photometric observations of the emission-line object AS 386. For the first time we found that it exhibits the B[e] phenomenon and fits the definition of an FS CMa type object. The optical spectrum shows the presence of a B-type star with the following properties: T eff = 11,000 ± 500 K, log L/L…
VLTI/MIDI atlas of disks around low- and intermediate-mass young stellar objects
Matter, A.; Jaffe, W.; Ábrahám, P. +13 more
Context. Protoplanetary disks show large diversity regarding their morphology and dust composition. With mid-infrared interferometry the thermal emission of disks can be spatially resolved, and the distribution and properties of the dust within can be studied.
Aims: Our aim is to perform a statistical analysis on a large sample of 82 disks ar…
Cas A and the Crab were not stellar binaries at death
Kochanek, C. S.
The majority of massive stars are in binaries, which implies that many core collapse supernovae should be binaries at the time of the explosion. Here we show that the three most recent, local (visual) SNe (the Crab, Cas A and SN 1987A) were not stellar binaries at death, with limits on the initial mass ratios of q = M2/M1 ≲ 0…
Can magnetic fields suppress convection in the atmosphere of cool white dwarfs? A case study on WD2105-820
Gänsicke, B. T.; Jordan, S.; Tremblay, P. -E. +3 more
Around 10 per cent of white dwarfs exhibit global magnetic structures with fields ranging from 1 kG to hundreds of MG. Recently, the first radiation magnetohydrodynamics simulations of the atmosphere of white dwarfs showed that convection should be suppressed in their photospheres for magnetic fields with strengths B ≳ 50 kG. These predictions are…
A Gaia study of the Hyades open cluster
Ventura, Paolo; Zari, Eleonora; de Bruijne, Jos +2 more
We present a study of the membership of the Hyades open cluster, derive kinematically modelled parallaxes of its members, and study the colour-absolute magnitude diagram of the cluster. We use Gaia DR1 Tycho-Gaia Astrometric Solution (TGAS) data complemented by Hipparcos-2 data for bright stars not contained in TGAS. We supplement the astrometric …
WASP-128b: a transiting brown dwarf in the dynamical-tide regime
Smalley, Barry; Hellier, Coel; Triaud, Amaury H. M. J. +15 more
Massive companions in close orbits around G dwarfs are thought to undergo rapid orbital decay due to runaway tidal dissipation. We report here the discovery of WASP-128b, a brown dwarf discovered by the WASP survey transiting a G0V host on a 2.2 d orbit, where the measured stellar rotation rate places the companion in a regime where tidal interact…
KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System
Cargile, Phillip A.; Bieryla, Allyson; Latham, David W. +65 more
We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of {1.586}-0.040+0.039 {R}{{J}}. We set an upper limit on the planetary mass of {M}P< 3.91 {M}{{J}} at 3σ confidenc…
Primeval very low-mass stars and brown dwarfs - IV. New L subdwarfs, Gaia astrometry, population properties, and a blue brown dwarf binary
Rebolo, R.; Zapatero Osorio, M. R.; Martín, E. L. +13 more
We present 27 new L subdwarfs and classify five of them as esdL and 22 as sdL. Our L subdwarf candidates were selected with the UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey. Spectroscopic follow-up was carried out primarily with the OSIRIS spectrograph on the Gran Telescopio Canarias. Some of these new objects were followed up with …
Gaia Data Release 2. Rotational modulation in late-type dwarfs
Audard, M.; Pagano, I.; Rimoldini, L. +12 more
Context. Amongst the ≈5 × 105 sources identified as variable stars in Gaia Data Release 2 (DR2), 26% are rotational modulation variable candidates of the BY Dra class. Gaia DR2 provides their multi-band (G, GBP, and GRP) photometric time series collected by the European Space Agency spacecraft Gaia during the first…
Dust reddening and extinction curves toward gamma-ray bursts at z > 4
Greiner, J.; Schady, P.; Krühler, T. +4 more
Context. Dust is known to be produced in the envelopes of asymptotic giant branch (AGB) stars, the expanded shells of supernova (SN) remnants, and in situ grain growth within the interstellar medium (ISM), although the corresponding efficiency of each of these dust formation mechanisms at different redshifts remains a topic of debate. During the f…