Search Publications
Extreme-ultraviolet Spectroscopic Observation of Direct Coronal Heating during a C-class Solar Flare
Brosius, Jeffrey W.
With the Coronal Diagnostic Spectrometer operating in rapid cadence (9.8 s) stare mode during a C6.6 flare on the solar disk, we observed a sudden brightening of Fe XIX line emission (formed at temperature T ≈ 8 MK) above the pre-flare noise without a corresponding brightening of emission from ions formed at lower temperatures, including He I (0.0…
Empirical near-infrared colors for low-mass stars and brown dwarfs in the Orion Nebula Cluster. An empirical near-infrared isochrone at ~1 Myr
Robberto, M.; Scandariato, G.; Da Rio, N. +2 more
Context. Current atmospheric and evolutionary models for low-mass stars and brown dwarfs rely on approximate assumptions on the physics of the stellar structure and the atmospheric radiative transfer. This leads to biased theoretical predictions on the photospheric spectral energy distributions of these system, especially when applied to low surfa…
Maser Observations of Westerlund 1 and Comprehensive Considerations on Maser Properties of Red Supergiants Associated with Massive Clusters
Hsia, Chih-Hao; Yung, Bosco H. K.; Nakashima, Jun-ichi +2 more
We report the results of Australia Telescope Compact Array observations of the Westerlund 1 (Wd1) region in the SiO v = 1, J = 1-0, and H2O 616-523 maser lines, and we also report the analysis of maser properties of red supergiants (RSGs) associated with six massive clusters including Wd1. The primary purpose of th…
Abrupt Changes of the Photospheric Magnetic Field in Active Regions and the Impulsive Phase of Solar Flares
Petrie, G. J. D.; Ling, A. G.; Cliver, E. W.
We compared time profiles of changes of the unsigned photospheric magnetic flux in active regions with those of their associated soft X-ray (SXR) bursts for a sample of 75 >= M5 flares well observed by Global Oscillation Network Group longitudinal magnetographs. Sixty-six of these events had stepwise changes in the spatially integrated unsigned…
The electromagnetic pickup of submicron-sized dust above Enceladus's northern hemisphere
Gurnett, Donald A.; Farrell, William M.; Kurth, William S. +3 more
As the saturnian magnetoplasma sweeps past Enceladus, it experiences both a decrease in electron content and sharp slowdown in the northern hemisphere region within ∼5 Enceladus Radii (Re). This slowdown is observed by Cassini in regions not obviously associated with the southern directed plume-originating ions. We suggest herein that t…
Kinematics of stars in the northern and southern galactic hemispheres
Tsvetkov, A. S.; Vityazev, V. V.
We use vector spherical harmonics for a kinematic analysis of the proper motions of stars from the Hipparcos, Tycho-2, and UCAC3 catalogues in the northern and southern Galactic hemispheres. We have found that the statistically reliable values of the Ogorodnikov-Milne model parameters M {32/+} and M {32/-
Ptolemy operations and results during the Lutetia flyby
Andrews, D. J.; Leese, M. R.; Zarnecki, J. C. +6 more
The September 5th 2008 Rosetta flyby of asteroid 2867 Šteins raised tantalising questions concerning the possibility of outgassing and extant exospheres surrounding small bodies within the asteroid belt. With this in mind and recognising the size and composition of asteroid 21 Lutetia it was decided to attempt a detection of such possible outgassi…
Orbits of the visual binaries ADS 8814 and ADS 8065 from observations along a short arc
Kiselev, A. A.; Romanenko, L. G.; Kiyaeva, O. V. +1 more
The orbits of the visual binaries ADS 8814 and ADS 8065 are determined for the first time. The orbits were calculated using the parameters of the apparent motion, based on position observations along short arcs obtained on the 26-inch refrector of the Pulkovo Observatory, supplemented with radial-velocity observations for the stellar components in…
The rates and time-delay distribution of multiply imaged supernovae behind lensing clusters
Richard, Johan; Hjorth, Jens; Li, Xue
Time delays of gravitationally lensed sources can be used to constrain the mass model of a deflector and determine cosmological parameters. We here present an analysis of the time-delay distribution of multiply imaged sources behind 17 strong lensing galaxy clusters with well-calibrated mass models. We find that for time delays less than 1000 days…
Proper Motions of the HH 110/270 System
Bally, J.; Raga, A. C.; Kajdič, P. +2 more
We present a study of the HH 110/270 system based on three sets of optical images obtained with the ESO New Technology Telescope, the Subaru Telescope, and the Hubble Space Telescope (HST). The ground-based observations are made in the Hα and [S II] emission lines and the HST observations are made in the Hα line only. Ground-based observations rev…