Search Publications
Classification of low-luminosity stellar X-ray sources in the field of the Draco dwarf spheroidal galaxy
Stelzer, Beate; Sasaki, Manami; Saeedi, Sara +1 more
Aims: A previous study of the X-ray luminosity function of the X-ray sources in the Draco dwarf spheroidal (dSph) galaxy field indicates the presence of a population of unknown X-ray sources in the soft energy range of 0.5-2 keV. In 2015, there were twenty-six further deep XMM-Newton observations of Draco dSph, providing an opportunity for a …
Comparison of neutral outgassing of comet 67P/Churyumov-Gerasimenko inbound and outbound beyond 3 AU from ROSINA/DFMS
Wurz, P.; Altwegg, K.; Berthelier, J. J. +16 more
Context. Pre-equinox measurements of comet 67P/Churyumov-Gerasimenko with the mass spectrometer ROSINA/DFMS on board the Rosetta spacecraft revealed a strongly heterogeneous coma. The abundances of major and various minor volatile species were found to depend on the latitude and longitude of the nadir point of the spacecraft. The observed time var…
A study of accretion and disk diagnostics in the NGC 2264 cluster
Alencar, Silvia H. P.; Calvet, Nuria; Sousa, Alana P. +3 more
Context. Understanding disk dissipation is essential for studying how planets form. Disk gaps and holes, which almost correspond to dust-free regions, are inferred from infrared observations of T Tauri stars (TTS), indicating the existence of a transitional phase between thick accreting disks and debris disks. Transition disks are usually referred…
Analysis of a long-lived, two-cell lightning storm on Saturn
Gurnett, D. A.; Kurth, W. S.; Delcroix, M. +4 more
Lightning storms in Saturn's atmosphere can last for a few days up to several months. In this paper we analyze a lightning storm that raged for seven and a half months at a planetocentric latitude of 35° south from the end of November 2007 until mid-July 2008. Thunderstorms observed by the Cassini spacecraft before this time were characterized by …
Hα emission-line stars in molecular clouds. III. Canis Major
Reipurth, Bo; Pettersson, Bertil
A deep objective-prism survey for Hα emission stars towards the Canis Major star-forming clouds was performed. A total of 398 Hα emitters were detected, 353 of which are new detections. There is a strong concentration of these Hα emitters towards the molecular clouds surrounding the CMa OB1 association, and it is likely that these stars are young …
Long X-ray flares from the central source in RCW 103. XMM-Newton and VLT observations in the aftermath of the 2016 outburst
Tiengo, A.; Rea, N.; Esposito, P. +7 more
We observed the slowly revolving pulsar 1E 161348-5055 (1E 1613, spin period of 6.67 h) in the supernova remnant RCW 103 twice with XMM-Newton and once with the Very Large Telescope (VLT). The VLT observation was performed on 2016 June 30, about a week after the detection of a large outburst from 1E 1613. At the position of 1E 1613, we found a nea…
The high-energy radiation environment of the habitable-zone super-Earth LHS 1140b
Campana, S.; Ghirlanda, G.; Ghisellini, G. +4 more
Context. In the last few years many exoplanets in the habitable zone (HZ) of M-dwarfs have been discovered, but the X-ray/UV activity of cool stars is very different from that of our Sun. The high-energy radiation environment influences the habitability, plays a crucial role for abiogenesis, and impacts the chemistry and evolution of planetary atm…
Colour-dependent accurate modelling of dynamical parallaxes and masses of visual binaries. Application to the VB+SB2 systems with definitive orbits
Andrade, Manuel
Context. Two fundamental characteristics of binary systems are the masses of their components and their distance to the Earth. In this way, the dynamical parallax is an accurate and very helpful tool. Nevertheless, there has been some concern with regard to the use of a unique linear mass-luminosity relation (MLR) for the entire main sequence (MS)…
Observational study of hydrocarbons in the bright photodissociation region of Messier 8
Menten, K. M.; Lee, M. -Y.; Wyrowski, F. +3 more
Aims: Hydrocarbons are ubiquitous in the interstellar medium, but their formation is still not well understood, depending on the physical environment in which they are found. Messier 8 (M8) is host to one of the brightest H II regions and photodissociation regions (PDRs) in our galaxy. With the observed C2H and c-C3H
Exploring the role of X-ray reprocessing and irradiation in the anomalous bright optical outbursts of A0538-66
Mereghetti, S.; Santangelo, A.; Ducci, L. +2 more
Context. In 1981, the Be/X-ray binary A0538-66 showed outbursts characterized by high peak luminosities in the X-ray (Lx ≈ 1039 erg s-1) and optical (Lopt ≈ 3 × 1038 erg s-1) bands. The bright optical outbursts were qualitatively explained as X-ray reprocessing in a gas cloud surrou…