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Fundamental parameters of the Ap-stars GO And, 84 UMa, and κ Psc
Sitnova, T. M.; Romanovskaya, A. M.; Ryabchikova, T. A. +1 more
Aims: The aim of this work is to determine fundamental parameters of three Ap stars, GO And (HD 4778), κ Psc (HD 220825), and 84 UMa (HD 120198), using spectroscopic techniques. By analysing these stars, we complete the sample of Ap stars for which fundamental parameters have additionally been derived by means of interferometry. This enables …
A nonlinear solar magnetic field calibration method for the filter-based magnetograph by the residual network
Ji, Kaifan; Su, Jiangtao; Deng, Yuanyong +6 more
Context. The method of solar magnetic field calibration for the filter-based magnetograph is normally the linear calibration method under weak-field approximation that cannot generate the strong magnetic field region well due to the magnetic saturation effect.
Aims: We try to provide a new method to carry out the nonlinear magnetic calibratio…
Subion-Scale Flux Rope Nested Inside Ion-Scale Flux Rope in Earth's Magnetotail
Wang, Z.; Liu, Y. Y.; Fu, H. S. +2 more
Magnetic flux ropes (MFRs)—transient magnetic structures widely observed in Earth's magnetosphere—play crucial roles in particle acceleration and energy dissipation. MFRs above ion scale have been well studied, while MFRs at subion scales and their coupling with larger-scale ropes still remains not well understood. In this paper, we present the fi…
Fe XVII 2p-3s Line Ratio Diagnostic of Shock Formation Radius in O Stars
Leutenegger, Maurice A.; Grell, Gabriel J.; Shah, Chintan
The 2p-3s lines of Fe XVII in the X-ray spectrum of the O-type star ζ Puppis exhibit an anomalous (3G + M2)/(3F) line ratio of ~1.4, in comparison with ~2.4 for almost all other collisionally excited astrophysical spectra. Based on the work of Mauche et al., we conjectured that the strong UV field of ζ Puppis produces the observed ratio by depopul…
VLBI Data Processing on Coronal Radio-sounding Experiments of Mars Express
Zhang, Peijin; Xiong, Ming; Xia, Bo +13 more
The ESA's Mars Express solar corona experiments were performed at two solar conjunctions in the years 2015 and 2017 by a number of radio telescopes in the European VLBI Network. This paper presents the methods to measure the frequency and phase fluctuations of the spacecraft radio signal, and the applications to study the characteristics of the pl…
Discovery of an M-type companion to the Herbig Ae Star V1787 Ori
Arun, R.; Mathew, Blesson; Manoj, P. +4 more
The intermediate-mass Herbig Ae star V1787 Ori is a member of the L1641 star-forming region in the Orion A molecular cloud. We report the detection of an M-type companion to V1787 Ori at a projected separation of 6.66 arcsec (corresponding to 2577 au), from the analysis of VLT/NACO adaptive optics Ks-band image. Using astrometric data f…
Configuration of a Magnetic Cloud from Solar Orbiter and Wind Spacecraft In-situ Measurements
Zhao, Lingling; Hu, Qiang; He, Wen +1 more
Coronal mass ejections (CMEs) represent one type of the major eruption from the Sun. Their interplanetary counterparts, the interplanetary CMEs (ICMEs), are the direct manifestations of these structures when they propagate into the heliosphere and encounter one or more observing spacecraft. The ICMEs generally exhibit a set of distinctive signatur…
Reconstructing the infilling history within Robert Sharp crater, Mars: Insights from morphology and stratigraphy
Mangold, Nicolas; Le Deit, Laetitia; Hauber, Ernst +2 more
Recent mineralogical studies suggest past aqueous activities in the 150-km-wide Robert Sharp impact crater, the western neighbor of Gale crater on Mars. Despite their mineralogical similarities, Robert Sharp and Gale craters display very different morphologies. Using high-resolution orbital images, we made morphological and stratigraphical analyse…
Thermal Pressures in the Interstellar Medium away from Stellar Environments
Tripp, Todd M.; Jenkins, Edward B.
Interstellar thermal pressures can be measured using C I absorption lines that probe the pressure-sensitive populations of the fine-structure levels of its ground state. In a survey of C I absorption toward Galactic hot stars, Jenkins & Tripp found evidence of small amounts (~0.05%) of gas at high pressures ( $p/k\gg {10}^{4}\,{\mat…
Infrared photometry and CaT spectroscopy of globular cluster M 28 (NGC 6626)
Minniti, D.; Zoccali, M.; Contreras Ramos, R. +12 more
Context. Recent studies show that the inner Galactic regions host genuine bulge globular clusters, but also halo intruders, complex remnants of primordial building blocks, and objects likely accreted during major merging events.
Aims: In this study we focus on the properties of M 28, a very old and massive cluster currently located in the Gal…