Search Publications
Venus night-side photometry with "cleaned" Akatsuki/IR2 data: Aerosol properties and variations of carbon monoxide
Sato, Takao M.; Satoh, Takehiko; Horinouchi, Takeshi +2 more
We have developed a novel method called Restoration by Simple Subtraction (RSS) to clean and restore the Venus night-side disk in "contaminated" Akatsuki/IR2 images at 2.26 and 1.735 µm. Light spread from the intense day crescent is cancelled by subtracting a near-simultaneous 2.32-µm image (scaled) from a 2.26-µm image. Net-cont…
Three New Late-type Stellar Companions to Very Dusty WISE Debris Disks Identified with SPHERE Imaging
Mamajek, Eric; Hinkley, Sasha; Crossfield, Ian J. M. +8 more
Debris disk stars are good targets for high-contrast imaging searches for planetary systems, since debris disks have been shown to have a tentative correlation with giant planets. We selected 20 stars identified as debris disk hosts by the WISE mission, with particularly high levels of warm dust. We observed these with the VLT/SPHERE high-contrast…
In-depth investigation of the physical origin of the soft X-ray excess in PG 1448+273
Gu, Qiusheng; Guo, Xiaotong; Ding, Nan +6 more
We present systematic X-ray spectral and variability analyses for the narrow-line Seyfert 1 galaxy (NLsy1), PG 1448+273, using the data from two long-exposure XMM-Newton observations of the source in the different flux states. These X-ray spectral analyses indicate that the two main-stream models of soft X-ray excess, the relativistically smeared …
OGLE-2007-BLG-224L: A Direct Test of Terrestrial Parallax
Yee, Jennifer C.; Bailey, Vanessa P.; Shan, Yutong +4 more
We present limits on the lens flux of OGLE-2007-BLG-224 based on MagAO imaging taken seven years after the microlensing event. At the time of the observations, the lens should have been separated from the microlensing source by 292 mas. However, no new sources are detected with MagAO. We place an upper limit on the lens flux of H > 20.57. This …
The Flux of Flux Ropes Embedded Within Magnetic Clouds Near 5 AU
Zhao, Yan; Feng, Hengqiang; Zhao, Guoqing +3 more
Magnetic clouds (MCs) are an important kind of interplanetary coronal mass ejections and generally treated as giant flux ropes. Previous researches indicates that the rope structure of MCs may be destructed as they move away from the solar surface. In this paper, we made a statistic study of the azimuthal flux of flux ropes embedded within MCs nea…
No Evidence for Time Variation in Saturn's Internal Magnetic Field
Cao, Hao; Bloxham, Jeremy; Moore, Kimberly M. +2 more
The time variation of a planetary magnetic field can reveal important aspects of a planet's interior structure. Searching for time variation in planetary magnetic fields other than Earth has proved challenging owing to the small number of spacecraft missions flown to date, but such a detection may be possible given a sufficiently long baseline for…
Using CME Progenitors to Assess CME Geoeffectiveness
Martens, Petrus; Aparna, V.; Mundra, Kashvi
There have been a few previous studies claiming that the effects of geomagnetic storms strongly depend on the orientation of the magnetic cloud portion of coronal mass ejections (CMEs). Aparna & Martens, using halo-CME data from 2007 to 2017, showed that the magnetic field orientation of filaments at the location where CMEs originate on the Su…
Searching for periodic variations in radial velocities after the removal of orbital motions of spectroscopic binaries
Sato, Bun'ei; Itoh, Yoichi; Katoh, Noriyuki
This study focuses on periodic variations of radial velocities (RVs) after removing the orbital motion of 33 spectroscopic binaries. The RVs were monitored from 2003 to 2012 and published in Katoh et al. (2013, AJ, 145, 41). Their RV precision was determined to be ∼10 m s-1 utilizing an I2 cell. We investigated the periodic v…
Martian roughness analogues of Europan terrains for radar sounder investigations
Gerekos, Christopher; Grima, Cyril; Steinbrügge, Gregor +5 more
Understanding the implications of Europa's roughness on backscattered radar signals is central to ensure that the future radar sounding instruments heading for the Jovian icy moons, the Radar for Icy Moons Exploration (RIME) and the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON), will yield fruitful observations over thei…
Towards realistic estimates of solar global oscillation mode-coupling measurement noise
Woodard, M. F.
Time series of the medium-l spherical-harmonic decomposition of SOHO/MDI Doppler images were used to investigate the noise of solar-oscillation mode-coupling measurements and to reveal the coupling signatures of global-scale Rossby-waves and magnetic activity. A theoretical model of mode-coupling noise was developed starting from the assumption th…