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A Hydro-based MCMC Analysis of SNR 0509-67.5: Revealing the Explosion Properties from Fluid Discontinuities Alone
Hughes, John P.; Arunachalam, Prasiddha; Hovey, Luke +1 more
Using Hubble Space Telescope/ACS Hα images of SNR 0509-67.5 taken ~10 yr apart, we measure the forward shock (FS) proper motions (PMs) at 231 rim locations. The average shock radius and velocity are 3.66 ± 0.036 pc and 6315 ± 310 km s-1. Hydrodynamic simulations, recast as similarity solutions, provide models for the supernova remnant's…
Study of the Magnetic Properties of Sunspot Umbrae
Obridko, V. N.; Fainshtein, V. G.; Rudenko, G. V. +1 more
The paper presents the results of the study of sunspots, obtained by the authors and other researchers in recent years. The results regarding the atmosphere above sunspot umbrae, based on the observational data in the spectral lines of the upper chromosphere and lower corona, are discussed. It is shown that individual parameters of the profile of …
Winds From the Visible (513 nm) Images Obtained by the Venus Monitoring Camera Onboard Venus Express
Ignatiev, N. I.; Zasova, L. V.; Titov, D. V. +4 more
We present more than 250,000 wind vectors derived from the visible (513 nm) images captured by the Venus Monitoring Camera (VMC) onboard ESA's Venus Express orbiter in the Southern hemisphere from 01 July 2007 to 29 January 2013. From comparison to the wind velocity derived from tracking of the descent probes, these measurements correspond to 60 ±…
The Dynamic Coupling of Streamers and Pseudostreamers to the Heliosphere
Antiochos, S. K.; Higginson, A. K.; Wyper, P. F. +3 more
The slow solar wind is generally believed to result from the interaction of open and closed coronal magnetic flux at streamers and pseudostreamers. We use three-dimensional magnetohydrodynamic simulations to determine the detailed structure and dynamics of open-closed interactions that are driven by photospheric convective flows. The photospheric …
Observed Rate Variations in Superflaring G-type Stars
Yang, Kai; Crowley, James; Wheatland, Michael S.
Flare occurrence on the Sun is highly variable, exhibiting both short-term variation due to the emergence and evolution of active regions, and long-term variation from the solar cycle. On solar-like stars, more energetic stellar flares (superflares) have been observed, and it is of interest to determine whether the observed rates of superflare occ…
Detection of spicules termed rapid blueshifted excursions as seen in the chromosphere via H α and the transition region via Si IV 1394 Å line emission
Shetye, Juie; Doyle, J. Gerry; Vilangot Nhalil, Nived
We show signatures of spicules termed rapid blueshifted excursions (RBEs) in the Si IV 1394 Å emission line using a semi-automated detection approach. We use the H α filtergrams obtained by the CRISP imaging spectropolarimeter on the Swedish 1-m Solar Telescope and co-aligned Interface Region Imaging Spectrograph data using the SJI 1400 Å channel …
A Ghost in Boötes: The Least-Luminous Disrupted Dwarf Galaxy
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +9 more
We report the discovery of Specter, a disrupted ultrafaint dwarf galaxy revealed by the H3 Spectroscopic Survey. We detected this structure via a pair of comoving metal-poor stars at a distance of 12.5 kpc, and further characterized it with Gaia astrometry and follow-up spectroscopy. Specter is a 25° × 1° stream of stars that is entirely invisible…
External or internal companion exciting the spiral arms in CQ Tau?
Testi, Leonardo; Benisty, Myriam; Pinte, Christophe +9 more
We present new high-contrast images in near-infrared wavelengths (λc = 1.04, 1.24, 1.62, 2.18, and 3.78 µm) of the young variable star CQ Tau, aiming to constrain the presence of companions in the protoplanetary disc. We reached a Ks-band contrast of 14 mag with SPHERE/IRDIS at separations greater than 0${_{.}^{\prime\prime}}$4 fr…
Massive young stellar objects in the Local Group spiral galaxy M 33 identified using machine learning
van Loon, Jacco Th; Oliveira, Joana M.; Kinson, David A.
We present a supervised machine learning classification of stellar populations in the Local Group spiral galaxy M 33. The Probabilistic Random Forest (PRF) methodology, previously applied to populations in NGC 6822, utilizes both near and far-IR classification features. It classifies sources into nine target classes: young stellar objects (YSOs), …
The Hubble PanCET Program: Emission Spectrum of Hot Jupiter HAT-P-41b
Deming, Drake; Mikal-Evans, Thomas; Sing, David K. +7 more
We present the most complete emission spectrum for inflated hot Jupiter HAT-P-41b combining new Hubble Space Telescope Wide Field Camera/G141 spectrum from the Hubble Panchromatic Comparative Exoplanet Treasury program with archival Spitzer eclipse observations. We found a near blackbody-like emission spectrum, which is best fitted with an isother…