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Constraining the orbit of the planet-hosting binary τ Boötis. Clues about planetary formation and migration
Albrecht, S.; Justesen, A. B.
Context. The formation of planets in compact or highly eccentric binaries and the migration of hot Jupiters are two outstanding problems in planet formation. Detailed characterisation of known systems is important for informing and testing models. The hot Jupiter τ Boo Ab orbits the primary star in the long-period (P ≳ 1000 yr), highly eccentric (…
X-ray spectra of Sagittarius A East and diffuse X-ray background near the Galactic center
Koyama, Katsuji; Nobukawa, Masayoshi; Uchiyama, Hideki +3 more
This paper reports the analysis procedure and results of simultaneous spectral fits of the Suzaku archive data for Sagittarius (Sgr) A East and the nearby Galactic center X-ray emission (GCXE). The results are that the mixed-morphology supernova remnant Sgr A East has a recombining plasma (RP) with Cr and Mn Heα lines, and a power-law component (P…
Spectroscopic study of the extremely young O-type triple system Herschel 36 A in the Hourglass nebula - I. Orbital properties
Morrell, Nidia I.; Barbá, Rodolfo H.; Maíz Apellániz, Jesús +3 more
We present a detailed spectroscopic study of Herschel 36 A (H36A), the main stellar component of the massive multiple system Herschel 36 in the Hourglass nebula, based on high-resolution optical spectra obtained along an 11 yr span. The three stellar components present in the spectrum of H36A are separated by means of a spectral disentangling tech…
Nearly coeval intermediate-age Milky Way star clusters at very different dynamics evolutionary stages
Piatti, Andrés E.; Dias, Wilton S.; Angelo, Mateus S.
We report astrophysical properties of 12 Milky Way open clusters located beyond a 2 kpc circle around the Sun by using deep optical photometry. We estimated their age and metallicities on the basis of a maximum likelihood approach using astrometric members determined from Gaia DR2 data. The studied clusters turned out to be of intermediate-age (0.…
Optical and X-ray correlations during the 2015 outburst of the black hole V404 Cyg
Dhillon, V. S.; Gandhi, P.; Marsh, T. R. +6 more
We present a serendipitous multiwavelength campaign of optical photometry simultaneous with Integral X-ray monitoring of the 2015 outburst of the black hole V404 Cyg. Large-amplitude optical variability is generally correlated with X-rays, with lags of order a minute or less compatible with binary light travel time-scales or jet ejections. Rapid o…
Near-infrared polarimetric study of near-Earth object 252P/LINEAR: an implication of scattered light from the evolved dust particles
Kwon, Jungmi; Tamura, Motohide; Im, Myungshin +7 more
Context. Comets undergo resurfacing due to solar radiation, while their primordial interiors remain unchanged. Multi-epoch observations of comets enable us to characterize a change in sublimation pattern as a function of heliocentric distance, which in turn provides information on the dust environments of comets.
Aims: We aim to constrain the…
Approximation for attraction field of irregular celestial bodies using four massive points
Burov, Alexander A.; Guerman, Anna D.; Nikonova, Ekaterina A. +1 more
Approximation of the gravitational field of an irregular celestial body by the gravitational attraction field of four massive points is studied here in the framework of K-means method, known from the theory of pattern recognition. Using this approach, the simplified models for gravitational fields of asteroid (1620) Geographos and comet (67P) Chur…
Investigating the origin of the spectral line profiles of the Hot Wolf-Rayet Star WR 2
Crowther, P. A.; Wade, G. A.; Chené, A. -N. +12 more
The hot WN star WR 2 (HD 6327) has been claimed to have many singular characteristics. To explain its unusually rounded and relatively weak emission line profiles, it has been proposed that WR 2 is rotating close to break-up with a magnetically confined wind. Alternatively, the line profiles could be explained by the dilution of WR 2's spectrum by…
The Arches cluster revisited. III. An addendum to the stellar census
Najarro, F.; Clark, J. S.; Patrick, L. R. +1 more
The Arches is one of the youngest, densest and most massive clusters in the Galaxy. As such it provides a unique insight into the lifecycle of the most massive stars known and the formation and survival of such stellar aggregates in the extreme conditions of the Galactic Centre. In a previous study we presented an initial stellar census for the Ar…
Arbitrariness of potentials in interacting quintessence models
Bamba, Kazuharu; Roy, Nandan
Though we have entered an era of high precision cosmology the form of the quintessence potentials still remain arbitrary. In this work we explore the interacting quintessence models considering a parametrization of the quintessence potentials and tried to constrain the form of potentials using the recent cosmological observations. The particular p…