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USNO Bright Star Catalog, Version 1
Harris, Hugh C.; Munn, Jeffrey A.; Subasavage, John P. +3 more
The USNO Bright Star Catalog (UBSC) is a new astrometric catalog of the 1423 brightest stars covering the entire sky, which is published online. It is nearly complete to V = 3 mag except for three stellar systems. A combined astrometric solution of the Hipparcos Intermediate Astrometry Data and two dedicated ground-based campaigns in 2013-2020 is …
Homologous Compact Major Blowout-eruption Solar Flares and their Production of Broad CMEs
Joshi, Bhuwan; Moore, Ronald L.; Sterling, Alphonse C. +2 more
We analyze the formation mechanism of three homologous broad coronal mass ejections (CMEs) resulting from a series of solar blowout-eruption flares with successively increasing intensities (M2.0, M2.6, and X1.0). The flares originated from NOAA Active Region 12017 during 2014 March 28-29 within an interval of ≈24 hr. Coronal magnetic field modelin…
Helium-like X-ray line complexes show that the hottest plasma on the O supergiant ζ Puppis is in its wind
Leutenegger, Maurice A.; Cohen, David H.; Gagné, Marc +3 more
We present an analysis of Chandra grating spectra of key helium-like line complexes to put constraints on the location with respect to the photosphere of the hottest (T ≳ 6 × 106 K) plasma in the wind of the O supergiant ζ Pup and to explore changes in the 18 yr between two sets of observations of this star. We fit two models - one empi…
Data-driven Derivation of Stellar Properties from Photometric Time Series Data Using Convolutional Neural Networks
Angus, Ruth; Huber, Daniel; Ness, Melissa K. +2 more
Stellar variability is driven by a multitude of internal physical processes that depend on fundamental stellar properties. These properties are our bridge to reconciling stellar observations with stellar physics and to understand the distribution of stellar populations within the context of galaxy formation. Numerous ongoing and upcoming missions …
Investigating the Accretion Nature of Binary Supermassive Black Hole Candidate SDSS J025214.67-002813.7
Shi, Fangzheng; Gültekin, Kayhan; Chen, Yu-Ching +3 more
We present results of a multiwavelength analysis of SDSS J025214.67-002813.7, a system that has been previously classified as a binary active galactic nucleus (AGN) candidate based on periodic signals detected in the optical light curves. We use available radio-X-ray observations of the system to investigate the true accretion nature. Analyzing ne…
Three-dimensional Magnetic and Thermodynamic Structures of Solar Microflares
Cheng, X.; Ding, M. D.; Chen, J. +2 more
Microflares, one of the small-scale solar activities, are believed to be caused by magnetic reconnection. Nevertheless, their three-dimensional (3D) magnetic structures, thermodynamic structures, and physical links to reconnection are unclear. In this Letter, based on a high-resolution 3D radiative magnetohydrodynamic simulation of the quiet Sun s…
A Morphometric Investigation of Large-Scale Crustal Shortening on Mars
Byrne, P. K.; Atkins, R. M.; Bohnenstiehl, D. R. +1 more
Mars' surface exhibits abundant topographic expressions of large thrust fault-related folds that have been attributed to global planetary contraction. Morphometric analyses of such structures provide insight into their growth history. With global THEMIS imagery and HRSC-MOLA topographic data, 49 thrusts with lengths between 35 and 544 km were mapp…
Magnetic gradiometry using frequency-domain filtering
Russell, Christopher T.; Raymond, Carol A.; Polanskey, Carol A. +7 more
Accurate measurements of ambient planetary and interplanetary magnetic fields using spacecraft magnetometers typically require accounting for interfering magnetic fields generated by the flight system (FS). The most common method for removing FS-generated time-variable magnetic fields is narrow-band and low-pass filtering of magnetic field data in…
SDSS-IV MaStar: Stellar parameter determination with continuum-supplemented full-spectrum fitting
Bizyaev, Dmitry; Beers, Timothy C.; Holtzman, Jon A. +13 more
Aims: We present a stellar parameter catalog built to accompany the MaStar Stellar Library, which is a comprehensive collection of empirical, medium-resolution stellar spectra.
Methods: We constructed this parameter catalog by using a multicomponent χ2 fitting approach to match MaStar spectra to models generated by interpolati…
Dawn-Dusk Ion Flow Asymmetry in the Plasma Sheet: Interplanetary Magnetic Field By Versus Distance With Respect to the Neutral Sheet
Hamrin, M.; Pitkänen, T.; Chong, Ghai Siung +1 more
Previous studies have shown that the average dawn-dusk component of the perpendicular plasma flow in the plasma sheet (V⊥) can vary depending on the distance relative to the neutral sheet and the dawn-dusk component of the interplanetary magnetic field (IMF By). In this study, we combined 33 years of data from the Geotail, Ti…