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The abundance of S- and Si-bearing molecules in O-rich circumstellar envelopes of AGB stars
Cernicharo, J.; Agúndez, M.; Velilla-Prieto, L. +1 more
Aims: We aim to determine the abundances of SiO, CS, SiS, SO, and SO2 in a large sample of oxygen-rich asymptotic giant branch (AGB) envelopes covering a wide range of mass loss rates to investigate the potential role that these molecules could play in the formation of dust in these environments.
Methods: We surveyed a sample …
Endogenic and Exogenic Contributions to Visible-wavelength Spectra of Europa's Trailing Hemisphere
Brown, Michael E.; Hand, Kevin P.; Trumbo, Samantha K.
The composition of Europa's trailing hemisphere reflects the combined influences of endogenous geologic resurfacing and exogenous sulfur radiolysis. Using spatially resolved visible-wavelength spectra of Europa obtained with the Hubble Space Telescope, we map multiple spectral features across the trailing hemisphere and compare their geographies w…
A spectroscopic test of the rotational modulation origin of periodic Kepler photometric variability of A-type stars
Wade, G. A.; Sikora, J.; Rowe, J.
High-precision space-based photometry obtained by the Kepler and TESS missions has revealed evidence of rotational modulation associated with main-sequence (MS) A- and late B-type stars. Generally, such variability in these objects is attributed to inhomogeneous surface structures (e.g. chemical spots), which are typically linked to strong magneti…
Activity and differential rotation of the early M dwarf Kepler-45 from transit mapping
Marsden, S. C.; Carter, B. D.; Valio, A. +1 more
Little is known of the activity and differential rotation of low luminosity, early M dwarfs from direct observation. We present the first stellar activity analysis of star-spots and faculae for the hot Jupiter hosting M1V dwarf Kepler-45 from Kepler transit light curves. We find star-spot and facula temperatures contrasting a few hundred degrees w…
Braking indices of young radio pulsars: theoretical perspective
Igoshev, Andrei P.; Popov, Sergei B.
Recently, Parthsarathy et al. analysed long-term timing observations of 85 young radio pulsars. They found that 15 objects have absolute values of braking indices ranging ∼10-3000, far from the classical value n = 3. They also noted a mild correlation between measured value of n and characteristic age of a radio pulsar. In this article, we systema…
From birth associations to field stars: mapping the small-scale orbit distribution in the Galactic disc
Xiang, Maosheng; Rix, Hans-Walter; El-Badry, Kareem +3 more
Stars born at the same time in the same place should have formed from gas of the same element composition. But most stars subsequently disperse from their birth siblings, in orbit and orbital phase, becoming 'field stars'. Here, we explore and provide direct observational evidence for this process in the Milky Way disc, by quantifying the probabil…
The Influence of Varying Spacecraft Potentials and Debye Lengths on In Situ Low-Energy Ion Measurements
Stenberg Wieser, Gabriella; Wieser, Martin; Eriksson, Anders +2 more
Low-energy ions are difficult to measure, mainly due to spacecraft charging. The ions are attracted to or repelled from the charged surface prior to detection, which changes both the energy and travel direction of the ions. This results in distortions of the data, and the changed travel directions distort the effective field of view (FOV) of the i…
Characteristics of solar wind suprathermal halo electrons
Fichtner, H.; Pierrard, V.; Lazar, M. +1 more
A suprathermal halo population of electrons is ubiquitous in space plasmas, as evidence of their departure from thermal equilibrium even in the absence of anisotropies. The origin, properties, and implications of this population, however, are poorly known. We provide a comprehensive description of solar wind halo electrons in the ecliptic, contras…
SCExAO/CHARIS Near-infrared Integral Field Spectroscopy of the HD 15115 Debris Disk
Henning, Thomas; Currie, Thayne; Schneider, Glenn +23 more
We present new, near-infrared (1.1-2.4 µm) high-contrast imaging of the debris disk around HD 15115 with the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system coupled with the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS). The SCExAO/CHARIS resolves the disk down to ρ ∼ 0"2 (rproj ∼ 10 au), a facto…
Hubble Space Telescope Imaging of Antlia B: Star Formation History and a New Tip of the Red Giant Branch Distance
Carlin, J. L.; Dolphin, A. E.; Crnojević, D. +8 more
A census of the satellite population around dwarf galaxy primary hosts in environments outside the Local Group is essential to understanding Λ cold dark matter galaxy formation and evolution on the smallest scales. We present deep optical Hubble Space Telescope imaging of the gas-rich, faint dwarf galaxy Antlia B (M V = -9.4)—a likely…