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On the Decay of Sunspot Groups and Their Internal Parts in Detail
Muraközy, Judit
The decay of sunspot groups is a relatively unknown field since most studies have focused mainly on the decay of sunspots or sunspot groups, but only on small samples. As an extension of the recent work of Muraközy (2020), which is based on a large verified sample, this study investigates not only the long-term behavior of the decay of sunspot gro…
Transport Characteristics of the Near-Surface Layer of the Nucleus of Comet 67P/Churyumov-Gerasimenko
Blum, J.; Agarwal, J.; Rezac, L. +4 more
The paper considers the free molecular flow of gas through the dusty porous surface layer of a comet nucleus. The study is based on computer models of generation of a porous medium and Knudsen gas diffusion. We consider various types of homogeneous and heterogeneous layers constructed from nonintersecting spheres, including layers that contain mic…
Solar wind temperature-velocity relationship over the last five solar cycles and Forbush decreases associated with different types of interplanetary disturbance
Melkumyan, A. A.; Belov, A. V.; Abunina, M. A. +4 more
The behaviour of the solar wind (SW) proton temperature and velocity and their relationship during Forbush decreases (FDs) associated with various types of solar source - coronal mass ejections (CMEs) and coronal holes (CHs) - have been studied. Analysis of cosmic ray variations, SW temperature, velocity, density, plasma beta, and magnetic field (…
Confirmation of ξ1 CMa's ultra-slow rotation: magnetic polarity reversal and a dramatic change in magnetospheric UV emission lines
Wade, G. A.; Fullerton, A. W.; Shultz, M. E. +5 more
The magnetic β Cep pulsator ξ1 CMa has the longest rotational period of any known magnetic B-type star. It is also the only magnetic B-type star with magnetospheric emission that is known to be modulated by both rotation and pulsation. We report here the first unambiguous detection of a negative longitudinal magnetic field in ξ1
Switchback-like structures observed by Solar Orbiter
Fedorov, A.; Lavraud, B.; Andre, N. +19 more
Context. Rapid polarity reversals of the radial heliospheric magnetic field were discovered by Ulysses and they are now frequently observed as a common near-Sun phenomenon by NASA's Parker Solar Probe (PSP). Other solar wind missions, including ESA-NASA Solar Orbiter (SolO), also observe similar phenomena. The nature of these fluctuations is uncle…
The Orbit and Density of the Jupiter Trojan Satellite System Eurybates-Queta
Buie, Marc W.; Noll, Keith S.; Levison, Harold F. +8 more
We report observations of the Jupiter Trojan asteroid (3548) Eurybates and its satellite Queta with the Hubble Space Telescope and use these observations to perform an orbital fit to the system. Queta orbits Eurybates with a semimajor axis of 2350 ± 11 km at a period of 82.46 ± 0.06 days and an eccentricity of 0.125 ± 0.009. From this orbit we der…
TOI-220 b: a warm sub-Neptune discovered by TESS
Bouchy, F.; Deeg, H.; Deleuil, M. +77 more
In this paper, we report the discovery of TOI-220 b, a new sub-Neptune detected by the Transiting Exoplanet Survey Satellite (TESS) and confirmed by radial velocity follow-up observations with the HARPS spectrograph. Based on the combined analysis of TESS transit photometry and high precision radial velocity measurements, we estimate a planetary m…
Multiwavelength view of SPT-CL J2106-5844. The radio galaxies and the thermal and relativistic plasmas in a massive galaxy cluster merger at z ≃ 1.13
Koribalski, Bärbel S.; Churazov, Eugene; Hopkins, Andrew M. +12 more
Context. SPT-CL J2106-5844 is among the most massive galaxy clusters at z > 1 yet discovered. While initially used in cosmological tests to assess the compatibility with Λ Cold Dark Matter cosmology of such a massive virialized object at this redshift, more recent studies indicate SPT-CL J2106-5844 is undergoing a major merger and is not an iso…
Magnetic properties on the boundary of an evolving pore
Jurčák, J.; Bello González, N.; García-Rivas, M.
Context. Analyses of the magnetic properties on umbrae boundaries have led to the Jurčák criterion, which states that umbra-penumbra boundaries in stable sunspots are equally defined by a constant value of the vertical magnetic field, Bvercrit, and by a 50% continuum intensity of the quiet Sun, IQS. Umbrae with ver…
Quiet-Sun Mg II h and k Line Profiles Derived from IRIS Full-Sun Mosaics. I. Reference Profiles and Center-to-limb Variation
Heinzel, Petr; Gunár, Stanislav; Koza, Július +2 more
We derived high-precision reference profiles of the Mg II h and k lines that represent the quiet Sun during a minimum of the solar activity. To do so, we used the broad catalog of full-Sun mosaics obtained by the Interface Region Imaging Spectrograph (IRIS). To minimize the influence of the local variations due to the on-disk solar features and to…