Search Publications
X-ray study of high-and-low luminosity modes and peculiar low-soft-and-hard activity in the transitional pulsar XSS J12270-4859
D'Avanzo, P.; Campana, S.; Miraval Zanon, A. +2 more
XSS J12270-4859 (henceforth J12270) is the first low-mass X-ray binary to exhibit a transition, taking place at the end of 2012, from an X-ray active state to a radio pulsar state. The X-ray emission based on archival XMM-Newton observations is highly variable, showing rapid variations (∼10 s) from a high X-ray luminosity mode to a low mode and ba…
Small-scale star formation as revealed by VVVX galactic cluster candidates
Minniti, D.; Chené, A. -N.; Alonso-García, J. +8 more
We report a search and analysis of obscured cluster candidates in the 'VISTA Variables in the Via Lactea eXtended (VVVX)' ESO Public Survey area encompassing the region between 229 ${_{.}^{\circ}}$ 4 < l < 295 ${_{.}^{\circ}}$ 2 and -4 ${_{.}^{\circ}}$ 3 < b < 4 ${_{.}^{\circ}}$ 4 of the southern Galactic disc. We discover and propose …
Astrometry and infrared observations of the Mira variable stars AP Lyncis, V837 Herculis, and BX Camelopardalis: Implications for the period-luminosity relation of the Milky Way
Fujimoto, Masayuki Y.; Nakagawa, Akiharu; Nagayama, Takahiro +6 more
AP Lyn and V837 Her are long-period Mira variable stars in the Milky Way. We performed VLBI Exploration of Radio Astrometry (VERA) phase-referenced observations towards H2O masers associated with AP Lyn and V837 Her. The annual parallaxes of AP Lyn and V837 Her were obtained to be 2.008 ± 0.038 mas and 1.090 ± 0.014 mas, corresponding t…
A Spectroscopic Classification Survey to Search for New ρ Puppis Stars
Gray, Richard O.; McGahee, Courtney; Griffin, R. E. M. +2 more
The ρ Puppis stars are mid-F-type stars that show peculiar chemical-abundance patterns similar to those of the Am stars. Typically they exhibit overabundances of iron-peak elements such as Fe and Ni and s- and r-process elements such as Sr and Eu, and underabundances of certain other elements including He, Ca, and Sc. It has been proposed that the…
A catalogue of open cluster radii determined from Gaia proper motions
Alfaro, Emilio J.; Sánchez, Néstor; López-Martínez, Fátima
In this work, we improve a previously published method to calculate in a reliable way the radius of an open cluster (OC). The method is based on the behaviour of stars in the proper motion space as the sampling changes in the position space. Here, we describe the new version of the method and show its performance and robustness. Additionally, we a…
Following the TraCS of exoplanets with Pan-Planets: Wendelstein-1b and Wendelstein-2b
Saglia, R. P.; Henning, Th.; Bender, R. +13 more
Hot Jupiters seem to get rarer with decreasing stellar mass. The goal of the Pan-Planets transit survey was the detection of such planets and a statistical characterization of their frequency. Here, we announce the discovery and validation of two planets found in that survey, Wendelstein-1b and Wendelstein-2b, which are two short-period hot Jupite…
The near-infrared companion to HD 94660 (=KQ Vel)
Hubrig, S.; Robrade, J.; Hummel, C. A. +4 more
Context. The Bp star HD 94660 is a single-lined spectroscopic binary. Some authors have suggested that the unseen companion of at least 2 M⊙ may be a compact object.
Aims: We intend to study this multiple system in detail, especially to learn more about the thus far unseen companion.
Methods: We have collected and analyzed PIO…
The Quadruple System HIP 45734
Tokovinin, Andrei
HIP 45734 is a quadruple system of 2 + 2 architecture located at 68 pc from the Sun. The outer 9″ system A,B has a period of ∼104 yr. The subsystem Aa,Ab is a visual binary with a period of 20.1 yr and an eccentricity of 0.78. Its periastron in 2019.1 was observed spectroscopically, yielding masses (1.10 ± 0.04 and 0.98 ± 0.03 ${{ \math…
X-ray Flux and Spectral Variability of Blazar H 2356-309
Gaur, Haritma; Wani, Kiran A.
We present the results of timing and spectral analysis of the blazar H 2356-309 using XMM-Newton observations. This blazar is observed during 13 June 2005–24 December 2013 in total nine observations. Five of the observations show moderate flux variability with amplitude 1.7–2.2%. We search for the intra-day variability timescales in these five lig…
Contribution of polar plumes to fast solar wind
Zangrilli, L.; Giordano, S. M.
Context. Several physical properties of solar polar plumes have been identified by different published studies, however such studies are rare and sometimes in disagreement.
Aims: The purpose of the present work is to analyze a set of SOHO/UVCS data dedicated to the observation of plumes and to obtain a picture of the physical properties of pl…