Search Publications
Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?
Li, Ting; Zhang, Jun; Chen, Huadong
From 2014 October 19 to 27, six X-class flares occurred in super active region (AR) 12192. They were all confined flares and were not followed by coronal mass ejections. To examine the structures of the four flares close to the solar disk center from October 22 to 26, we firstly employ composite triple-time images in each flare process to display …
Non-potential Field Formation in the X-shaped Quadrupole Magnetic Field Configuration
Shimizu, T.; Inoue, S.; Kawabata, Y.
Some types of solar flares are observed in X-shaped quadrupolar field configuration. To understand the magnetic energy storage in such a region, we studied non-potential field formation in an X-shaped quadrupolar field region formed in the active region NOAA 11967, which produced three X-shaped M-class flares on 2014 February 2. Nonlinear force-fr…
Long-term monitoring of comet 67P/Churyumov-Gerasimenko's jets with OSIRIS onboard Rosetta
Jorda, L.; Lamy, P. L.; Lara, L. M. +47 more
We used the OSIRIS camera system onboard the Rosetta spacecraft to monitor jet activity of comet 67P/Churyumov-Gerasimenko. With a monthly cadence, we covered an epoch from 2014 December to 2015 October, thereby including the first equinox and the perihelion passage. Jet features were measured in individual images, which were used to perform a sta…
Beyond 3 au from the Sun: The Hypervolatiles CH4, C2H6, and CO in the Distant Comet C/2006 W3 (Christensen)
Villanueva, Geronimo L.; Mumma, Michael J.; DiSanti, Michael A. +5 more
Comet C/2006 W3 (Christensen) remained outside a heliocentric distance (R h) of 3.1 au throughout its apparition, but it presented an exceptional opportunity to directly sense a suite of molecules released from its nucleus. The Cryogenic Infrared Echelle Spectrograph at ESO-VLT detected infrared emissions from the three “hypervolatiles”…
A Large Catalog of Homogeneous Ultra-Violet/Optical GRB Afterglows: Temporal and Spectral Evolution
Gronwall, Caryl; Kuin, N. P. M.; Roming, Peter W. A. +10 more
We present the second Swift Ultra-Violet/Optical Telescope (UVOT) gamma-ray burst (GRB) afterglow catalog, greatly expanding on the first Swift UVOT GRB afterglow catalog. The second catalog is constructed from a database containing over 120,000 independent UVOT observations of 538 GRBs first detected by Swift, the High Energy Transient Explorer 2…
On the east-west longitudinally asymmetric distribution of solar proton events
Wan, W.; He, H. -Q.
A large data set of 78 solar proton events observed near the Earth's orbit during 1996-2011 is investigated. An east-west longitudinal (azimuthal) asymmetry is found to exist in the distribution of flare sources of solar proton events. With the same longitudinal separation between the flare sources and the magnetic field line footpoint of observer…
Angular Momentum Evolution of Young Stars in the nearby Scorpius-Centaurus OB Association
Oberst, Thomas E.; Mamajek, Eric E.; Mellon, Samuel N. +1 more
We report the results of a study of archival SuperWASP light curves for stars in Scorpius-Centaurus (Sco-Cen), the nearest OB association. We use SuperWASP time-series photometry to extract rotation periods for 189 candidate members of the Sco-Cen complex and verify that 162 of those are members of the classic Sco-Cen subgroups of Upper Scorpius (…
HST/COS Far-ultraviolet Spectroscopic Analysis of U Geminorum Following a Wide Outburst
Sion, Edward M.; Godon, Patrick; Shara, Michael M. +1 more
We used the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) to obtain a series of four far-ultraviolet (FUV; 915-2148 Å) spectroscopic observations of the prototypical dwarf nova U Geminorum during its cooling following a two-week outburst. Our FUV spectral analysis of the data indicates that the white dwarf (WD) cools from a…
Faint warm debris disks around nearby bright stars explored by AKARI and IRSF
Inutsuka, Shu-ichiro; Onaka, Takashi; Kaneda, Hidehiro +5 more
Context. Debris disks are important observational clues for understanding planetary-system formation process. In particular, faint warm debris disks may be related to late planet formation near 1 au. A systematic search of faint warm debris disks is necessary to reveal terrestrial planet formation.
Aims: Faint warm debris disks show excess em…
Mid-infrared observations of O-type stars: spectral morphology
Bouret, J. -C.; Audard, M.; Lanz, T. +2 more
We present mid-infrared (mid-IR) observations for a sample of 16 O-type stars. The data were acquired with the NASA Spitzer Space Telescope, using the IRS instrument at moderate resolution (R ∼ 600), covering the range of ∼10-37 µm. Our sample includes early, mid and late O supergiants and dwarfs. We explore for the first time their mid-IR s…