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Investigating the origin of gypsum in Olympia Undae: Characterizing the mineralogy of the basal unit
Mustard, J. F.; Das, E.; Tarnas, J. D. +2 more
The Olympia Undae sand sea contains the largest known deposit of gypsum discovered on the surface of Mars. The origin of this gypsum, a hydrated sulfate mineral requiring liquid water for its formation, remains largely unconstrained. We examine the hypothesis that gypsum was derived from the early-Amazonian aged Basal Unit, which is suggested to c…
Uniting the Sun's Hale magnetic cycle and "extended solar cycle" paradigms
McIntosh, Scott W.; Leamon, Robert J.; Scherrer, Philip H. +1 more
Through meticulous daily observation of the Sun's large-scale magnetic field the Wilcox Solar Observatory (WSO) has catalogued two magnetic (Hale) cycles of solar activity. Those two (∼22-year long) Hale cycles have yielded four (∼11-year long) sunspot cycles (numbers 21 through 24). Recent research has highlighted the persistence of the "Extended…
Could the Magnetic Star HD 135348 Possess a Rigidly Rotating Magnetosphere?
Gagliano, Robert; Jayaraman, Rahul; Ricker, George R. +5 more
We report the detection and characterization of a new magnetospheric star, HD 135348, based on photometric and spectropolarimetric observations. The TESS light curve of this star exhibited variations consistent with stars known to possess rigidly rotating magnetospheres (RRMs), so we obtained spectropolarimetric observations using the Robert Stobi…
Atmospheric processes affecting methane on Mars
Rauer, H.; Arnold, G.; Herbst, K. +6 more
It is currently uncertain as to whether methane exists on Mars. Data from the Curiosity Rover suggests a background methane concentration of a few tenths parts per billion whereas data from the Trace Gas Orbiter suggest an upper limit of twenty parts per trillion. If methane exists on Mars then we do not understand fully the physical and chemical …
Probing the megaparsec-scale environment of hyperluminous infrared galaxies at 2 < z < 4
Wang, L.; Farrah, D.; Clements, D. +3 more
Context. Protoclusters are progenitors of galaxy clusters and they serve as an important key in studies of how halo mass and stellar mass assemble in the early universe. Finding the signposts of such overdense regions, such as bright dusty star-forming galaxies (DSFG), is a popular method for identifying protocluster candidates.
Aims: Hyperlu…
A machine learning approach to photometric metallicities of giant stars
Sanders, Jason L.; Fallows, Connor P.
Despite the advances provided by large-scale photometric surveys, stellar features - such as metallicity - generally remain limited to spectroscopic observations often of bright, nearby low-extinction stars. To rectify this, we present a neural network approach for estimating the metallicities and distances of red giant stars with 8-band photometr…
GRB 190919B: Rapid optical rise explained as a flaring activity
Karpov, Sergey; Hu, Y. -D.; Castro-Tirado, Alberto J. +17 more
Following the detection of a long GRB 190919B by INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory), we obtained an optical photometric sequence of its optical counterpart. The light curve of the optical emission exhibits an unusually steep rise ∼100 s after the initial trigger. This behaviour is not expected from a `canonical' GRB optical…
Probing the innermost region of the AU Microscopii debris disc
Milli, J.; Boccaletti, A.; Girard, J. H. +5 more
Context. AU Mic is a young and nearby M-dwarf star harbouring a circumstellar debris disc and one recently discovered planet on an eight-day orbit. Large-scale structures within the disc were also discovered and are moving outwards at high velocity.
Aims: We aim to study this system with the highest spatial resolution in order to probe the in…
No globular cluster progenitors in Milky Way satellite galaxies
Bovy, Jo; Boldrini, Pierre
In order to find the possible progenitors of Milky Way (MW) globular clusters, we perform orbit integrations to track the orbits of 170 Galactic globular clusters and the 11 classical MW satellite galaxies backwards in time for 11 Gyr in an MW-plus-satellites potential including the response of the MW to the infall of the Large Magellanic Cloud an…
CoSHA: Code for Stellar Properties Heuristic Assignment-for the MaStar Stellar Library
Yan, Renbin; Drory, Niv; Bruzual, Gustavo +5 more
We introduce COSHA: a Code for Stellar properties Heuristic Assignment. In order to estimate the stellar properties, COSHA implements a Gradient Tree Boosting algorithm to label each star across the parameter space (T eff, $\mathrm{log}g$ , [Fe/H], and [α/Fe]). We use COSHA to estimate the stellar atmospheric parameters of 22,000 unique…