Search Publications
Variability survey of brightest stars in selected OB associations
Tuvikene, Taavi; Eenmäe, Tõnis; Kolka, Indrek +2 more
Context. The stellar evolution theory of massive stars remains uncalibrated with high-precision photometric observational data mainly due to a small number of luminous stars that are monitored from space. Automated all-sky surveys have revealed numerous variable stars but most of the luminous stars are often overexposed. Targeted campaigns can imp…
Orion revisited. III. The Orion Belt population
Bouy, H.; Burkert, A.; Sarro, L. M. +11 more
Aims: This paper continues our study of the foreground population to the Orion molecular clouds. The goal is to characterize the foreground population north of NGC 1981 and to investigate the star formation history in the large Orion star-forming region. We focus on a region covering about 25 square degrees, centered on the ɛ Orionis supergia…
Temporal and spatial variations of the absolute reflectivity of Jupiter and Saturn from 0.38 to 1.7 µm with PlanetCam-UPV/EHU
Hueso, R.; Sánchez-Lavega, A.; Rojas, J. F. +3 more
Aims: We provide measurements of the absolute reflectivity of Jupiter and Saturn along their central meridians in filters covering a wide range of visible and near-infrared wavelengths (from 0.38 to 1.7 µm) that are not often presented in the literature. We also give measurements of the geometric albedo of both planets and discuss the l…
Automated detection of coronal mass ejections in three-dimensions using multi-viewpoint observations
Morgan, H.; Hutton, J.
A new, automated method of detecting coronal mass ejections (CMEs) in three dimensions for the LASCO C2 and STEREO COR2 coronagraphs is presented. By triangulating isolated CME signal from the three coronagraphs over a sliding window of five hours, the most likely region through which CMEs pass at 5 R⊙ is identified. The centre and size…
CSI 2264: Simultaneous optical and X-ray variability in pre-main sequence stars. I. Time resolved X-ray spectral analysis during optical dips and accretion bursts in stars with disks
Micela, G.; Stauffer, J.; Sciortino, S. +6 more
Context. Pre-main sequence stars are variable sources. The main mechanisms responsible for their variability are variable extinction, unsteady accretion, and rotational modulation of both hot and dark photospheric spots and X-ray-active regions. In stars with disks, this variability is related to the morphology of the inner circumstellar region (≤…
Bars as seen by Herschel and Sloan
Consolandi, Guido; Gavazzi, Giuseppe; Dotti, Massimo +2 more
We present an observational study of the effect of bars on the gas component and on the star formation properties of their host galaxies in a statistically significant sample of resolved objects, the Herschel Reference Sample. The analysis of optical and far-infrared images allows us to identify a clear spatial correlation between stellar bars and…
An abundance analysis from the STIS-HST UV spectrum of the non-magnetic Bp star HR 6000
Leone, F.; Castelli, F.; Catanzaro, G. +2 more
Context. The sharp-line spectrum of the non-magnetic, main-sequence Bp star HR 6000 has peculiarities that distinguish it from those of the HgMn stars with which it is sometimes associated. The position of the star close to the center of the Lupus 3 molecular cloud, whose estimated age is on the order of 9.1 ± 2.1 Myr, has lead to the hypothesis t…
The spectroscopic indistinguishability of red giant branch and red clump stars
Masseron, T.; Hawkins, K.
Context. Stellar spectroscopy provides useful information on the physical properties of stars such as effective temperature, metallicity and surface gravity. However, those photospheric characteristics are often hampered by systematic uncertainties. The joint spectro-sismo project (APOGEE+Kepler, aka APOKASC) of field red giants has revealed a puz…
Observational signatures of past mass-exchange episodes in massive binaries: the case of LSS 3074
Gosset, E.; Rauw, G.; Manfroid, J. +4 more
Context. The role of mass and momentum exchanges in close massive binaries is very important in the subsequent evolution of the components. Such exchanges produce several observational signatures such as asynchronous rotation and altered chemical compositions, that remain after the stars detach again.
Aims: We investigated these effects for t…
Direct probe of the inner accretion flow around the supermassive black hole in NGC 2617
Costantini, E.; Miniutti, G.; Motta, S. E. +12 more
Aims: NGC 2617 is a nearby (z 0.01) active galaxy that recently switched from being a Seyfert 1.8 to be a Seyfert 1.0. At the same time, it underwent a strong increase of X-ray flux by one order of magnitude with respect to archival measurements. We characterise the X-ray spectral and timing properties of NGC 2617 with the aim of studying the…