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Tracing Milky Way substructure with an RR Lyrae hierarchical clustering forest
Mahabal, Ashish A.; Rebbapragada, Umaa; Cook, Brian T. +6 more
RR Lyrae variable stars have long been reliable standard candles used to discern structure in the Local Group. With this in mind, we present a routine to identify groupings containing a statistically significant number of RR Lyrae variables in the Milky Way environment. RR Lyrae variable groupings, or substructures, with potential Galactic archaeo…
Spectral Lines in FUV and EUV for Diagnosing Coronal Magnetic Field
Nagaraju, K.; Khan, Raveena
The diagnostic capabilities of spectral lines in the far-ultraviolet (FUV) and extreme-ultraviolet (EUV) wavelength ranges are explored in terms of their Hanle and Zeeman sensitivity to probe the vector magnetic fields in the solar corona. The temperature range covered is log10(T)=5.5 - 6.3. The circular-polarization signal due to longi…
Solar Observations with Single-Dish INAF Radio Telescopes: Continuum Imaging in the 18 - 26 GHz Range
Iacolina, M. N.; Pellizzoni, A.; Egron, E. +28 more
We present a new solar radio imaging system implemented through the upgrade of the large single-dish telescopes of the Italian National Institute for Astrophysics (INAF), not originally conceived for solar observations.
Accurate Ground-based Astrometry of Naked-eye Stars: The United States Naval Observatory Bright-star Astrometric Database
Harris, Hugh C.; Munn, Jeffrey A.; Subasavage, John P. +1 more
We present the United States Naval Observatory (USNO) Bright-star Astrometric Database (UBAD), a current-epoch high-accuracy astrometric catalog. The catalog consists of 364 bright northern hemisphere stars, including all but five such stars with either V < 3.5 or with I < 3.2 and V < 6, as well as a large fraction of slightly fainter sta…
Evidence for a Dense, Inhomogeneous Circumstellar Medium in the Type Ia SNR 0519-69.0
Petre, Robert; Reynolds, Stephen P.; Ghavamian, Parviz +3 more
We perform an expansion study of the Balmer-dominated outer shock of the SNR 0519-69.0 in the LMC by using a combination of new Hubble Space Telescope (HST) WFC3 imagery obtained in 2020 and archival ACS images from 2010 and 2011. Thanks to the very long time baseline, our proper motion measurements are of unprecedented accuracy. We find a wide ra…
HCN and HCO+ in Planetary Nebulae: The Next Level
Ziurys, L. M.; Schmidt, D. R.; Gold, K. R. +2 more
Observations of HCN and HCO+ have been carried out toward 13 planetary nebulae (PNe) using the facilities of the Arizona Radio Observatory (ARO). These nebulae represent a wide range of morphologies and ages (~2000-28,000 yr). For both molecules, the J = 1 → 0 transitions at 88-89 GHz and the J = 3 → 2 lines at 265-267 GHz were measured…
Orbital solution and dynamical masses for the nearby binary system GJ 67 AB
Torres, Guillermo
We report spectroscopic observations of the nearby, 19.5-yr binary system GJ 67AB spanning more than 35 yr. We carry out a global orbital solution combining our radial-velocity measurements with others from the literature going back more than a century, and with all other available astrometric observations. The latter include measurements of the r…
Regional Geology of the Hypanis Valles System, Mars
Bell, James F.; Dobrea, Eldar Noe; Adler, Jacob B. +2 more
We present a geomorphic map of the Hypanis Valles watershed and a geomorphic map of the Hypanis deposit region at its terminus. We mapped these two regions at different scales: 1:2,000,000 for the catchment map (−5° to 10°N and 300°-315°E) and 1:500,000 for the Hypanis deposit map (10°-13.0°N and 313°-316.5°E). Our mapping provides new morphologic…
Optical spectroscopy of the Be/black hole binary MWC 656 - interaction of a black hole with a circumstellar disc
Bode, Michael F.; Stefanov, Stefan Y.; Marchev, Dragomir +7 more
We present new spectroscopic observations of the Be/black hole binary MWC 656 obtained during the period 2015-2021. We measure the equivalent width of Hα (EWα), Hβ (EWβ), and the distance between the peaks of Hα (ΔVα), Hβ (ΔVβ), and FeII (ΔVFeII) lines. Combining new and old data, we find that…
Pulse Timing Discovery of a Three-day Companion to the Hot Subdwarf BPM 36430
Hermes, J. J.; Barlow, Brad N.; Schaffenroth, Veronika +2 more
Hot subdwarf B stars are core-helium-burning objects that have undergone envelope stripping, likely by a binary companion. Using high-speed photometry from the Transiting Exoplanet Survey Satellite, we have discovered the hot subdwarf BPM 36430 is a hybrid sdBVrs pulsator exhibiting several low-amplitude g-modes and a strong p-mode puls…