Search Publications
Detection of nitrogen gas in the β Pictoris circumstellar disc
Snellen, I. A. G.; Lecavelier des Etangs, A.; Bourrier, V. +4 more
Context. The gas composition of the debris disc surrounding β Pictoris is rich in carbon and oxygen relative to solar abundances. Two possible scenarios have been proposed to explain this enrichment. The preferential production scenario suggests that the produced gas may be naturally rich in carbon and oxygen, while the alternative preferential de…
Detailed X-ray spectroscopy of the magnetar 1E 2259+586
Tiengo, A.; Israel, G.; Mereghetti, S. +7 more
Magnetic field geometry is expected to play a fundamental role in magnetar activity. The discovery of a phase-variable absorption feature in the X-ray spectrum of SGR 0418+5729, interpreted as cyclotron resonant scattering, suggests the presence of very strong non-dipolar components in the magnetic fields of magnetars. We performed a deep XMM-Newt…
New powerful outburst of the unusual young star V1318 Cygni S (LkHα 225)
Magakian, T. Yu.; Movsessian, T. A.; Andreasyan, H. R. +1 more
Aims: Young double star V1318 Cyg, which is associated with a small isolated star-forming region around HAeBe star BD+40°4124, has very unusual photometric and spectral behavior. We present results of photometric and spectroscopic observations in the optical range.
Methods: We carried out BVRI CCD photometric observations of V1318 Cyg fr…
Molecular gas content of shell galaxies
Duc, P. -A.; Combes, F.; Mancillas, B.
Shells are fine stellar structures that are identified by their arc-like shapes around a galaxy. They are currently thought to be vestiges of galaxy interactions and/or mergers. The study of their number, geometry, stellar populations, and gas content can help us to derive the interaction or merger history of a galaxy. Numerical simulations have p…
Inversion of HIPPARCOS and Gaia photometric data for asteroids. Asteroid rotational properties from sparse photometric data
Tanga, P.; Cellino, A.; Hestroffer, D. +2 more
Context. Sparse photometric data can be used to determine the spin properties and infer information about the shapes of asteroids. The algorithm adopted for the inversion of Gaia photometric data assumes, for the sake of simplicity and to minimize CPU execution time, that the objects have triaxial ellipsoid shapes. In the past, this algorithm was …
The origin of R CrA variability. A complex triple system hosting a disk
Messina, S.; D'Orazi, V.; Desidera, S. +5 more
Context. R CrA is the brightest member of the Coronet star-forming region and is the closest Herbig AeBe star with a spectrum dominated by emission lines. Its luminosity has been monitored since the end of the nineteenth century, but the origin of its variability, which shows a stable period of 65.767 ± 0.007 days, is still unknown.
Aims: We …
Three-Dimensional Optimal Spectral Extraction (TDOSE) from integral field spectroscopy
Inami, H.; Schmidt, K. B.; Krajnović, D. +8 more
The amount of integral field spectrograph (IFS) data has grown considerably over the last few decades. The demand for tools to analyze such data is therefore bigger now than ever. We present a flexible Python tool for Three-Dimensional Optimal Spectral Extraction (TDOSE) from IFS data cubes. TDOSE works on any three-dimensional data cube and bases…
Precise radial velocities of giant stars. XIII. A second Jupiter orbiting in 4:3 resonance in the 7 CMa system
Quirrenbach, A.; Grundahl, F.; Albrecht, S. +8 more
We report the discovery of a second planet orbiting the K giant star 7 CMa based on 166 high-precision radial velocities obtained with Lick, HARPS, UCLES, and SONG. The periodogram analysis reveals two periodic signals of approximately 745 and 980 d, associated with planetary companions. A double-Keplerian orbital fit of the data reveals two Jupit…
The Hubble Catalog of Variables (HCV)
Hatzidimitriou, D.; Rest, A.; Georgantopoulos, I. +33 more
Aims: Over its lifetime and despite not being a survey telescope, the Hubble Space Telescope (HST) has obtained multi-epoch observations by multiple, diverse observing programs, providing the opportunity for a comprehensive variability search aiming to uncover new variables. We have therefore undertaken the task of creating a catalog of varia…
Pronounced morphological changes in a southern active zone on comet 67P/Churyumov-Gerasimenko
Lamy, P. L.; Lara, L. M.; Bertaux, J. -L. +30 more
A smooth deposit in the southern Khonsu region has been seen in ESA/Rosetta observations as active during the second half of 2015, when the southern summer coincided with the perihelion passage of 67P/Churyumov-Gerasimenko (67P). Image color sequences acquired by the OSIRIS instrument in the period of January 2015 to July 2016, pre- and post-perih…