Search Publications
New Spatially Resolved Imaging of the SR 21 Transition Disk and Constraints on the Small-grain Disk Geometry
van der Marel, N.; Ireland, M. J.; Puglisi, A. +9 more
We present new 0.6-4 µm imaging of the SR 21 transition disk from Keck/NIRC2 and Magellan/MagAO. The protoplanetary disk around SR 21 has a large (∼30-40 au) clearing first inferred from its spectral energy distribution and later detected in submillimeter imaging. Both the gas and small dust grains are known to have a different morphology, w…
Disentangling the Arcturus stream
Kushniruk, Iryna; Bensby, Thomas
Context. The Arcturus stream is an over-density of stars in velocity space and its origin has been much debated recently without any clear conclusion. The (classical) dissolved open cluster origin is essentially refuted; instead the discussions try to distinguish between an accretion, a resonant, or an external-perturbation origin for the stream. …
The GAPS Programme with HARPS-N at TNG. XVIII. Two new giant planets around the metal-poor stars HD 220197 and HD 233832
Scandariato, G.; Pagano, I.; Poretti, E. +40 more
Context. Statistical studies of exoplanets have shown that giant planets are more commonly hosted by metal-rich dwarf stars than low-metallicity stars, while no such correlation is evident for lower mass planets. The search for giant planets around metal-poor stars and the estimate of their occurrence fp is an important element in provi…
Four Metal-poor Stars in the Sagittarius Dwarf Spheroidal Galaxy
Frebel, Anna; Chiti, Anirudh
We present the metallicities and carbon abundances of four newly discovered metal-poor stars with -2.2 < [Fe/H] < -1.6 in the Sagittarius dwarf spheroidal galaxy. These stars were selected as metal-poor member candidates using a combination of public photometry from the SkyMapper Southern Sky Survey and proper-motion data from the second dat…
Multi-scale analysis of the Monoceros OB 1 star-forming region. I. The dense core population
Sanhueza, Patricio; Soam, Archana; Doi, Yasuo +24 more
Context. Current theories and models attempt to explain star formation globally, from core scales to giant molecular cloud scales. A multi-scale observational characterisation of an entire molecular complex is necessary to constrain them. We investigate star formation in G202.3+2.5, a ∼10 × 3 pc sub-region of the Monoceros OB1 cloud with a complex…
Comparing extrapolations of the coronal magnetic field structure at 2.5 R⊙ with multi-viewpoint coronagraphic observations
Sasso, C.; Romoli, M.; Andretta, V. +19 more
The magnetic field shapes the structure of the solar corona, but we still know little about the interrelationships between the coronal magnetic field configurations and the resulting quasi-stationary structures observed in coronagraphic images (such as streamers, plumes, and coronal holes). One way to obtain information on the large-scale structur…
Parametric Study of ICME Properties Related to Space Weather Disturbances via a Series of Three-Dimensional MHD Simulations
Moon, Yong-Jae; Magara, Tetsuya; Hayashi, Keiji +1 more
Interplanetary coronal mass ejections (ICMEs) are important drivers of space-weather disturbances observed at the Earth. We use a parameterized ICME model to investigate the relation between the physical properties of an ICME and these disturbances. Compared to those studies focused on deriving a best set of ICME parameter values matched with obse…
On the Power-Law Distribution of Pitch-Angle Scattering Times in Solar Wind Turbulence
Zimbardo, Gaetano; Perri, Silvia; Pucci, Francesco +1 more
The propagation of energetic particles in the solar wind depends in a sensitive way on the pitch-angle scattering of particles in the presence of magnetic turbulence. The well-known quasi-linear theory gives an expression for the pitch-angle scattering rate under the assumption of small turbulence levels, but both in the solar wind and in other as…
Identifications of faint Chandra sources in the globular cluster M3
Heinke, Craig O.; Cool, Adrienne M.; Zhao, Yue +2 more
We report a 30 ksChandra ACIS-S survey of the globular cluster M3. Sixteen X-ray sources were detected within the half-light radius (2.3 arcmin) with L_X ≳ 2.3 × 10^{31} erg s^{-1}. We used Hubble Space Telescope WFC3/UVIS and ACS/WFC images to find 10 plausible optical/UV counterparts. We fit the spectral energy distribution of the known cataclys…
Diurnal variation of dust and gas production in comet 67P/Churyumov-Gerasimenko at the inbound equinox as seen by OSIRIS and VIRTIS-M on board Rosetta
Lamy, P. L.; Lara, L. M.; Bertaux, J. -L. +53 more
Context. On 27 April 2015, when comet 67P/Churyumov-Gerasimenko was at 1.76 au from the Sun and moving toward perihelion, the OSIRIS and VIRTIS-M instruments on board the Rosetta spacecraft simultaneously observed the evolving dust and gas coma during a complete rotation of the comet.
Aims: We aim to characterize the spatial distribution of d…