Search Publications
TYC 8241 2652 1 and the case of the disappearing disk: No smoking gun yet
Kraus, Stefan; Weigelt, Gerd; Sitko, Michael +12 more
Context. TYC8241 2652 1 is a young star that showed a strong mid-infrared (mid-IR, 8-25 µm) excess in all observations before 2008, which is consistent with a dusty disk. Between 2008 and 2010 the mid-IR luminosity of this system dropped dramatically by at least a factor of 30 suggesting a loss of dust mass of an order of magnitude or more. …
Orbit of the mercury-manganese binary 41 Eridani
Hubrig, S.; Hummel, C. A.; Schöller, M. +1 more
Context. Mercury-manganese (HgMn) stars are a class of slowly rotating chemically peculiar main-sequence late B-type stars. More than two-thirds of the HgMn stars are known to belong to spectroscopic binaries.
Aims: By determining orbital solutions for binary HgMn stars, we will be able to obtain the masses for both components and the distanc…
HIP 21539 is not a past very close neighbour of the Sun
Panuzzo, P.; Sartoretti, P.; Soubiran, C. +3 more
Aims: A previous study claimed that the star HIP 21539 passed close to the Sun, at a distance of 1.9 pc, around 0.14 Myr ago. We show that this is not the case.
Methods: We redetermined the trajectory of the star relative to the Sun using a new accurate radial velocity from the HARPS spectrograph combined with the recent Gaia-TGAS astrom…
Distant clusters of galaxies in the 2XMM/SDSS footprint: follow-up observations with the LBT
Takey, A.; Schwope, A.; Lamer, G. +1 more
Context. Galaxy clusters at high redshift are important to test cosmological models and models for the growth of structure. They are difficult to find in wide-angle optical surveys, however, leaving dedicated follow-up of X-ray selected candidates as one promising identification route.
Aims: We aim to increase the number of galaxy clusters be…
Solar-insolation-induced changes in the coma morphology of comet 67P/Churyumov-Gerasimenko. Optical monitoring with the Nordic Optical Telescope
Snodgrass, C.; Schulz, R.; Nilsson, K. +4 more
Context. 67P/Churyumov-Gerasimenko (67P/C-G) is a short-period Jupiter family comet with an orbital period of 6.55 yr. Being the target comet of ESA's Rosetta mission, 67P/C-G has become one of the most intensively studied minor bodies of the solar system. The Rosetta Orbiter and the Philae Lander have brought us unique information about the struc…
Dust and gas environment of the young embedded cluster IRAS 18511+0146
Testi, L.; Walmsley, C. M.; Vig, S. +2 more
Context. Since massive and intermediate mass stars form in clusters, a comparative investigation of the environments of the young embedded cluster members can reveal significant information about the conditions under which stars form and evolve.
Aims: IRAS 18511+0146 is a young embedded (proto)cluster located at 3.5 kpc surrounding what appea…
Age of the magnetically active WW Psa and TX Psa members of the β Pictoris association
Messina, S.; Petrucci, R.; Jofré, E. +6 more
Context. There are a variety of different techniques available to estimate the ages of pre-main-sequence stars. Components of physical pairs, thanks to their strict coevality and the mass difference, such as the binary system analyzed in this paper, are best suited to test the effectiveness of these different techniques.
Aims: We consider the…
A test field for Gaia. Radial velocity catalogue of stars in the South Ecliptic Pole
Meisenheimer, K.; Gosset, E.; Boudreault, S. +25 more
Context. Gaia is a space mission that is currently measuring the five astrometric parameters, as well as spectrophotometry of at least 1 billion stars to G = 20.7 mag with unprecedented precision. The sixth parameter in phase space (I.e., radial velocity) is also measured thanks to medium-resolution spectroscopy that is being obtained for the 150 …
A likely detection of a local interplanetary dust cloud passing near the Earth in the AKARI mid-infrared all-sky map
Onaka, T.; Kaneda, H.; Ishihara, D. +8 more
Context. We are creating the AKARI mid-infrared all-sky diffuse maps. Through a foreground removal of the zodiacal emission, we serendipitously detected a bright residual component whose angular size is about 50° × 20° at a wavelength of 9 µm.
Aims: We investigate the origin and the physical properties of the residual component.
Me…
Latitude dependence of the solar granulation during the minimum of activity in 2009
Utz, D.; Hanslmeier, A.; Muller, R.
Context. Knowledge of the latitude variation of the solar granulation properties (contrast and scale) is useful to better understand interactions between magnetic field, convection, differential rotation, and meridional circulation in the solar atmosphere.
Aims: We investigated the latitude dependence of the contrast and scale of the solar gr…