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Is the Young Star Association ϵ Cha Double?
Bobylev, V. V.; Bajkova, A. T.
The kinematics of the ϵ Cha young stellar association close to the Sun has been studied based on a list of candidate stars from the Dickson-Vandervelde et al. work. The working sample consists of 26 stars with parallaxes, proper motions from the Gaia DR3 catalog and radial velocities taken from literary sources. The orbits of the stars back to the…
XUV irradiation of young planetary atmospheres. Results from a joint XMM-Newton and HST observation of HIP67522
Micela, G.; Benatti, S.; Pillitteri, I. +3 more
Context. The evaporation and the chemistry of the atmospheres of warm and hot planets are strongly determined by the high-energy irradiation they receive from their parent stars. This is more crucial among young extra-solar systems because of the high activity of stars at early ages. In particular, the extreme-ultraviolet (EUV) part of the stellar…
An X-Ray Significantly Variable, Luminous, Type 2 Quasar at z = 2.99 with a Massive Host Galaxy
Marchesi, Stefano; Gilli, Roberto; Zhao, Xiurui +8 more
We present a comprehensive X-ray analysis and spectral energy distribution (SED) fitting of WISEA J171419.96+602724.6, an extremely luminous type 2 quasar at z = 2.99. The source was suggested as a candidate Compton-thick (column density N H > 1.5×1024 cm‑2) quasar by a short XMM-Newton observation in 2011. We r…
KM UMa: An Active Short-period Detached Eclipsing Binary in a Hierarchical Quadruple System
Meng, Fangbin; Zhu, Liying; Liu, Nianping +4 more
The first detailed photometric and spectroscopic analysis of the G-type eclipsing binary KM UMa is presented, which indicates that the system is a short-period detached eclipsing binary. The radial velocity curves were calculated using the cross-correlation function method based on Large Sky Area Multi-Object Fiber Spectroscopic Telescope, Sloan D…
Variability of the Ultraluminous X-ray Source M 74 X-1 in X-ray and Optical Ranges
Atapin, K. E.; Vinokurov, A. S.; Solovyeva, Yu. N. +1 more
Using observations of M 74 X-1 obtained with the Chandra X-ray Observatory and the Hubble Space Telescope, we identified this source in the optical range. Analysis of other archival data allowed us to track the evolution of M 74 X-1 over two decades of observations, as well as to search for a correlation between the object's variability in the X-r…
Detection of Two Totally Eclipsing B-type Binaries with Extremely Low Mass Ratios
Qian, Shengbang; Li, Fuxing; Zang, Lei +1 more
The detection of O- and B-type stars with extremely low-mass companions is very important for understanding the formation and evolution of binary stars. However, finding them remains a challenge because the low-mass components in such systems contribute such small flux to the total. During our search for pulsations among O- and B-type stars using …
The Digitized First Byurakan Survey Database Late-Type Stars Candidates. New Confirmations. II
Gigoyan, K. K.; Gigoyan, K. S.; Kostandyan, G. R. +5 more
Three new carbon C stars was confirmed among the sample of the Late-Type Stars candidates, selected on the Digitized First Byurakan Survey (DFBS) spectral plates. The DFBS is the digitized version of the First Byurakan Survey (FBS, or Markarian survey). The FBS was the first systematic survey of the extragalactic sky. This objective-prism survey w…
The GAPS Programme at TNG: LVIII. Two multi-planet systems with long-period substellar companions around metal-rich stars
Scandariato, G.; Marzari, F.; Sozzetti, A. +20 more
Context. Due to observational biases, a large fraction of known exoplanets are short-period objects. However, the search for planets began more than 20 yr ago, and so it is already possible – with the use of a suitable dataset – to begin exploring a wider range of the parameter space, such as that encompassing long-period planets. Aims. The aim of…
First deep X-ray observations of the Fermi-detected steep-spectrum source and radio-loud NLS1 galaxy 3C 286
Komossa, S.; Grupe, D.; Kraus, A. +1 more
A well-known calibrator source in radio astronomy, 3C 286 ($z=0.85$), is a compact steep-spectrum (CSS) radio source and spectroscopically classified as a narrow-line Seyfert 1 (NLS1) galaxy. It is also known for its damped Ly $\alpha$ system from an intervening galaxy at $z=0.692$ detected in both ultraviolet (UV) and radio spectra. In addition, …
X Persei: A study on the origin of its high-energy emission
Fiocchi, M.; Natalucci, L.; Rodi, J.
Aims. The origin of the hard X-ray emission in the Be/X-ray binary system X Persei has long been debated as its atypical 'two-hump' spectrum can be modelled in multiple ways. The main debate focuses on the the high-energy hump, which is fit as either a cyclotron resonance scatter frequency (CRSF) or inverse Comptonization due to bulk Comptonizatio…