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Hot gas heating via magnetic arms in spiral galaxies. The case of M 83
Ehle, M.; Weżgowiec, M.; Soida, M. +3 more
Context. Reconnection heating has been considered as a potential source of the heating of the interstellar medium. In some galaxies, significant polarised radio emission has been found between the spiral arms. This emission has a form of "magnetic arms" that resembles the spiral structure of the galaxy. Reconnection effects could convert some of t…
A Dust Trap in the Young Multiple System HD 34700
Wilner, David J.; Zhang, Qizhou; Rich, Evan A. +6 more
Millimeter observations of disks around young stars reveal substructures indicative of gas pressure traps that may aid grain growth and planet formation. We present Submillimeter Array observations of HD 34700: two Herbig Ae stars in a close binary system (Aa/Ab, ∼0.25 au), surrounded by a disk presenting a large cavity and spiral arms seen in sca…
A search for the modern counterparts of the Far Eastern guest stars 369 CE, 386 CE and 393 CE
Hoffmann, Susanne M.; Vogt, Nikolaus
In this study, we apply our previously developed method to investigate ancient transient sightings in order to derive consequences for modern astrophysical problems. We present case studies of three observations of so-called guest stars in the fourth century CE, which lasted several months each. These three observations had been discussed and sugg…
A Model of the Dust Envelope of the Carbon Mira Star V CrB from Photometry, Infrared Spectroscopy, and Speckle Polarimetry
Safonov, B. S.; Tatarnikov, A. M.; Shenavrin, V. I. +2 more
$UBVJHKLM$ photometry for the carbon Mira star V CrB are presented. The infrared observations were carried out in the time interval 1989-2018, while the $U$, $B$, and $V$ data were obtained in 2001-2014. The light and color curves are analyzed. The pulsation period of V CrB has been found to be $355\overset{\textrm{d}}{.}2$ in the infrared $JHKLM$…
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…