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Updated values of solar gravitational moments J2n using HMI helioseismic inference of internal rotation
Meftah, M.; Mecheri, R.
The solar gravitational moments J2n are important astronomical quantities whose precise determination is relevant for solar physics, gravitational theory and high precision astrometry, and celestial mechanics. Accordingly, we propose in the present work to calculate new values of J2n (for n = 1, 2, 3, 4, and 5) using recent t…
Solar Orbiter's first Venus flyby. MAG observations of structures and waves associated with the induced Venusian magnetosphere
Maksimovic, M.; Bale, S. D.; Horbury, T. S. +18 more
Context. The induced magnetosphere of Venus is caused by the interaction of the solar wind and embedded interplanetary magnetic field with the exosphere and ionosphere of Venus. Solar Orbiter entered Venus's magnetotail far downstream, > 70 Venus radii, of the planet and exited the magnetosphere over the north pole. This offered a unique view o…
Nonlinear Magnetic Gradients and Complete Magnetic Geometry From Multispacecraft Measurements
Russell, C. T.; Rong, Zhaojin; Shen, Chao +8 more
Topological configurations of the magnetic field play key roles in the dynamics of space plasmas. This study presents a novel algorithm that can estimate the quadratic magnetic gradient as well as the complete geometrical features of magnetic field lines, based on magnetic field and current density measurements by a multiple spacecraft constellati…
BAT99-9 - a WC4 Wolf-Rayet star with nitrogen emission: evidence for binary evolution?
Aadland, Erin; Massey, Philip; Hillier, D. John +1 more
An analysis of the Large Magellanic Cloud (LMC) WC4 star BAT99-9 (HD 32125, FD 4, Brey 7, WS 3) shows that the star still contains photospheric nitrogen. Three N emission features (N V λλ1238, 1242, N IV λ1719, and N IV λλ3479-3485) are unambiguously identified in the spectrum. CMFGEN models of the star yield an N/C ratio of 0.004 ± 0.002 (by numb…
Using Chandra Localizations and Gaia Distances and Proper Motions to Classify Hard X-Ray Sources Discovered by INTEGRAL
Hare, Jeremy; Fornasini, Francesca M.; Bodaghee, Arash +7 more
Here, we report on X-ray observations of ten 17-60 keV sources discovered by the International Gamma-Ray Astrophysics Laboratory satellite. The primary new information is sub-arcsecond positions obtained by the Chandra X-ray Observatory. In six cases (IGR J17040-4305, IGR J18017-3542, IGR J18112-2641, IGR J18434-0508, IGR J19504+3318, and IGR J200…
Angular Diameters and Fundamental Parameters of Forty-four Stars from the Navy Precision Optical Interferometer
van Belle, Gerard T.; Schmitt, Henrique R.; Baines, Ellyn K. +9 more
We measured the angular diameters of 44 stars with the Navy Precision Optical Interferometer, obtaining uncertainties on the limb-darkened diameter of 2% or less for all but four stars. We then used our diameters with Gaia or Hipparcos parallaxes to calculate each star's physical radius. We gathered information from the literature to determine bol…
A Deep Study of an Intermediate-age Open Cluster SAI 35 (Juchert 20) Using Ground-based Imaging and Gaia EDR3 Astrometry
Bisht, D.; Rangwal, Geeta; Yadav, R. K. S. +4 more
We present a CCD UBVI photometric study of poorly studied intermediate-age open cluster SAI 35 (Juchert 20) for the first time. To accomplish this study, we also used LAMOST DR5, Two Micron All Sky Survey, and Gaia EDR3 databases. We identified 214 most probable cluster members with membership probability higher than 50%. The mean proper motion of…
Neutral-neutral synthesis of organic molecules in cometary comae
Charnley, S. B.; Cordiner, M. A.
Remote and in situ observations of cometary gases have revealed the presence of a wealth of complex organic molecules, including carbon chains, alcohols, imines, and the amino acid glycine. Such chemical complexity in cometary material implies that impacts by comets could have supplied reagents for prebiotic chemistry to young planetary surfaces. …
The Geographic Distribution of Dense-phase O2 on Ganymede
Brown, Michael E.; Trumbo, Samantha K.; Adams, Danica
Ground-based spectroscopy of Ganymede's surface has revealed the surprising presence of dense-phase molecular oxygen (O2) via weak absorptions at visible wavelengths. To date, the state and stability of this O2 at the temperatures and pressures of Ganymede's surface are not understood. Its spatial distribution in relation to …
Short-period Variability in the Globular Cluster NGC 419 and the SMC Field
Martínez-Vázquez, C. E.; Vivas, A. K.; Salinas, R.
Delta Scuti (δ Sct) stars have been extensively studied in our Galaxy but far less in extragalactic systems. Here we study the population of δ Sct variables in NGC 419, an intermediate-age globular cluster of the Small Magellanic Cloud (SMC), using g, r, and i Gemini-S/Gemini Multi-Object Spectrograph (GMOS) time-series observations. Our goal is t…