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Scaling slowly rotating asteroids with stellar occultations
Geier, S.; Urbanik, M.; Pál, A. +176 more
Context. As evidenced by recent survey results, the majority of asteroids are slow rotators (spin periods longer than 12 h), but lack spin and shape models because of selection bias. This bias is skewing our overall understanding of the spins, shapes, and sizes of asteroids, as well as of their other properties. Also, diameter determinations for l…
Generating Photospheric Vector Magnetograms of Solar Active Regions for SOHO/MDI Using SDO/HMI and BBSO Data with Deep Learning
Xu, Yan; Jing, Ju; Wang, Haimin +6 more
Solar activity is often caused by the evolution of solar magnetic fields. Magnetic field parameters derived from photospheric vector magnetograms of solar active regions (ARs) have been used to analyze and forecast eruptive events, such as solar flares and coronal mass ejections. Unfortunately, the most recent Solar Cycle 24 was relatively weak wi…
Ion Energization and Thermalization in Magnetic Reconnection Exhaust Region in the Solar Wind
Verscharen, Daniel; He, Jiansen; Fedorov, Andrey +7 more
Plasma energization and thermalization in magnetic reconnection is an important topic in astrophysical studies. We select two magnetic reconnection exhausts encountered by Solar Orbiter and analyze the associated ion heating in the kinetic regime. Both cases feature asymmetric plasma merging in the exhaust and anisotropic heating. For a quantitati…
Automated classification of Chandra X-ray point sources using machine learning methods
Bhattacharyya, Sudip; Kumaran, Shivam; Mandal, Samir +1 more
A large number of unidentified sources found by astronomical surveys and other observations necessitate the use of an automated classification technique based on machine learning (ML) methods. The aim of this paper is to find a suitable automated classifier to identify the point X-ray sources in the Chandra Source Catalogue (CSC) 2.0 in the catego…
PENELLOPE. V. The magnetospheric structure and the accretion variability of the classical T Tauri star HM Lup
Kóspál, Á.; Alcalá, J. M.; Manara, C. F. +9 more
HM Lup is a young M-type star that accretes material from a circumstellar disk through a magnetosphere. Our aim is to study the inner disk structure of HM Lup and to characterize its variability. We used spectroscopic data from HST/STIS, X-shooter, and ESPRESSO taken in the framework of the ULLYSES and PENELLOPE programs, together with photometric…
Photospheric and Chromospheric Magnetic Field Evolution during the X1.6 Flare in Active Region NOAA 12192
Guglielmino, S. L.; Romano, P.; Zuccarello, F. +2 more
We report on observations acquired by the Interferometric Bidimensional Spectropolarimeter (IBIS) during SOL2014-10-22T14:02, an X1.6 flare that occurred in active region NOAA 12192, taken in the Fe I 617.30 nm and Ca II 854.2 nm line profiles. We analyze polarization signatures in the Stokes profiles of the two lines across one of the flare ribbo…
Slowly rotating close binary stars in Cassini states
Fuller, Jim; Felce, Catherine
Recent asteroseismic measurements have revealed a small population of stars in close binaries, containing primaries with extremely slow rotation rates. Such stars defy the standard expectation of tidal synchronization in such systems, but they can potentially be explained if they are trapped in a spin-orbit equilibrium known as Cassini state 2 (CS…
Cassini Radio Occultation Observations of Saturn's Ionosphere: Electron Density Profiles From 2005 to 2013
Withers, Paul; Dalba, P. A.; Moore, L. +2 more
A set of electron density profiles of Saturn's ionosphere acquired by Cassini radio occultations is archived at the NASA Planetary Data System. However, the reference surface that defines zero altitude in these profiles is unknown and appears to vary by 1,500 km at fixed latitude. These profiles are immensely valuable for addressing questions pert…
Supersoft luminous X-ray sources in galactic nuclei
Miniutti, G.; Risaliti, G.; Sacchi, A.
Context. Tidal disruption events (TDEs) are usually discovered at X-ray or optical wavelengths through their transient nature. A characteristic spectral feature of X-ray detected TDEs is a `supersoft' X-ray emission, not observed in any other extragalactic source, with the exception of a few rapidly variable hyperluminous X-ray sources (HLXs) or s…
Atmospheric and Fundamental Parameters of the Individual Components of Multiple Stellar Systems
Al-Wardat, Mashhoor A.; Abu-Alrob, Enas M.; Hussein, Abdallah M.
We present detailed analyses of eight triple stellar systems (lying between 20 and 155 pc) and nine quadruple stellar systems (lying between 20 and 250 pc) with different configurations. Most of these systems are hierarchical. The systems are HIP 4239, HIP 5588, HIP 11072, HIP 12548, HIP 13498, HIP 17895, HIP 19915, HIP 22607, HIP 25240, HIP 28614…