Search Publications
The Ice Content of the Dorsa Argentea Formation From Radar Sounder Data
Plaut, Jeffrey J.; Whitten, Jennifer L.; Campbell, Bruce A.
The Dorsa Argentea Formation (DAF) is an extensive Hesperian plains unit in the south polar region of Mars that was once ice rich and may still contain a substantial fraction of water ice. Given its 3.5-Ga age, the possibility for massive ice in the DAF has significant implications for the preservation of volatiles during large obliquity changes. …
A survey for variable young stars with small telescopes - III. Warm spots on the active star V1598 Cyg
Scholz, Aleks; Eislöffel, Jochen; Froebrich, Dirk +1 more
Magnetic spots on low-mass stars can be traced and characterized using multiband photometric light curves. Here, we analyse an extensive data set for one active star, V1598 Cyg, a known variable K dwarf which is either pre-main sequence and/or in a close binary system. Our light curve contains 2854 photometric data points, mostly in V, Rc
The first stellar parallaxes revisited
Menten, Karl M.; Reid, Mark J.
We have reanalyzed the data used by Bessel, von Struve, and Henderson in the 1830s to measure the first parallax distances to stars. We can generally reproduce their results, although we find that von Struve and Henderson have underestimated some of their measurement errors, leading to optimistic parallax uncertainties. We find that temperature co…
The corona of GJ 1151 in the context of star-planet interaction
Schmitt, J. H. M. M.; Poppenhaeger, K.; Alvarado-Gómez, J. D. +1 more
The low-mass star GJ 1151 has been reported to display variable low-frequency radio emission, which has been interpreted as a signpost of coronal star-planet interactions with an unseen exoplanet. Here we report the first X-ray detection of GJ 1151's corona based on the XMM-Newton data. We find that the star displays a small flare during the X-ray…
Identification of Two Distinct Electron Populations in an Impulsive Solar Energetic Electron Event
Wang, L.; Zhao, L.; Li, G. +2 more
We examine the release times of energetic electrons in the 2001 April 25 event. An M2.7 flare occurred on 2001 April 25, from AR 09433, located at N18W09. The flare was observed in X-rays by GOES and the Yohkoh spacecraft. The Yohkoh observation also included hard X-ray (HXR) images for all four energy channels: L, M1, M2, and H. We use Yohkoh obs…
Comparing Observed Stellar Kinematics and Surface Densities in a Low-latitude Bulge Field to Galactic Population Synthesis Models
Anderson, Jay; Penny, Matthew T.; Bennett, David P. +3 more
We present an analysis of Galactic bulge stars from Hubble Space Telescope Wide Field Camera 3 observations of the Stanek window (l, b = [0.25, -2.15]) from two epochs approximately two years apart. This data set is adjacent to the provisional Wide-field Infrared Survey Telescope (WFIRST) microlensing field. Proper motions are measured for approxi…
A Wide-orbit Exoplanet OGLE-2012-BLG-0838Lb
Soszyński, I.; Udalski, A.; Szymański, M. K. +50 more
We present the discovery of a planet on a very wide orbit in the microlensing event OGLE-2012-BLG-0838. The signal of the planet is well separated from the main peak of the event and the planet-star projected separation is found to be twice the Einstein ring radius, which corresponds to a projected separation of ≈4 au. Similar planets around low-m…
HCN 3-2 survey towards a sample of local galaxies
Fang, Min; Li, Shanghuo; Wang, Junzhi +4 more
We present observations of HCN 3-2 emissions towards 37 local galaxies using the 10 m Submillimeter Telescope. HCN 3-2 emission is detected in 23 galaxies. The correlation of infrared luminosity (LIR) and the luminosity of HCN 3-2 line emission measured in our sample is fitted with a slope of 1.11 and correlation coefficient of 0.91, wh…
Globular Clusters Lost by the Sagittarius Dwarf Spheroidal Galaxy
Sharina, M. E.; Arakelyan, N. R.; Pilipenko, S. V.
—In this work a search was carried out for globular clusters belonging to the Sagittarius (Sgr) tidal stream using the analysis of spatial positions, radial velocities relative to the Galactic Standard of Rest (VGSR), proper motions and ratio of "age–metallicity" ([Fe/H]) for globular clusters and for stars in the tidal stream. As a res…
What Determines Solar Flares Producing Interplanetary Type III Radio Bursts?
Liu, Y.; Cheng, X.; Ding, M. D. +4 more
Energetic electrons accelerated by solar flares often give rise to type III radio bursts at a broad wave band and even interplanetary type III bursts (IT3) if the wavelength extends to a decameter-kilometer. In this Letter, we investigate the probability of the flares that produce IT3, based on the sample of 2272 flares above M-class observed from…