Search Publications
Tidal Quality of the Hot Jupiter WASP-12b
Makarov, Valeri V.; Efroimsky, Michael
WASP-12b stands out among the planets of its class of hot Jupiters because of the observed fast orbital decay attributed to tidal dissipation. The measured rate of the orbital period change is Pṡorb=‑29±3ms/yr= ‑(9.2±1.0)×10‑10s/s. In the literature heretofore, all attempts to explain this high rate were based on the assumption that the orbital ev…
The Effect of Age on the Grouping of Open Clusters: The Primordial Group Hypothesis
Casado, Juan
The Primordial Group hypothesis states that only sufficiently young open clusters (OCs) can be multiple, and old OCs are essentially isolated. We tested this postulate through four different studies using a manual search of Gaia EDR3 and extensive literature. First, we revisited the work of de La Fuente Marcos and de La Fuente Marcos (2009), which…
The C/M Ratio of AGB Stars in the Local Group Galaxies
Yang, Ming; Ren, Yi; Jiang, Biwei +1 more
The number ratio of carbon-rich to oxygen-rich asymptotic giant branch (AGB) stars (the so-called C/M ratio) is closely related to the evolution environment of the host galaxy. This work studies the C/M ratio in 14 galaxies within the Local Group with the most complete and clean sample of member stars identified in our previous works. The borderli…
Solar Orbiter SWA Observations of Electron Strahl Properties Inside 1 AU
Verscharen, Daniel; Louarn, Philippe; Owen, Christopher J. +3 more
The Solar Wind Analyser (SWA) suite on Solar Orbiter includes an Electron Analyser System (SWA-EAS) which is capable of high temporal and angular resolution measurements of solar wind electrons in the energy range ∼1 eV to ∼5 keV. In this article we report early nominal phase observations of the suprathermal electron population at energies ≥70 eV …
Mechanical Properties of Cometary Surfaces
Vincent, Jean-Baptiste; Biele, Jens; Knollenberg, Jörg
Mechanical properties, in particular, strength (tensile, shear, compressive) and porosity, are important parameters for understanding the evolution and activity of comets. However, they are notoriously difficult to measure. Unfortunately, neither Deep Impact nor other comet observations prior to Rosetta provided firm data on the strength of cometa…
Exploring the Fundamental Mechanism in Driving Highest-Velocity Ionized Outflows in Radio AGNs
Xue, Yongquan; Woo, Jong-Hak; He, Zhicheng +4 more
We investigate the ionized gas kinematics relationship with X-ray, radio and accreting properties using a sample of 348 nearby (z<0.4) SDSS-FIRST-X-ray detected AGNs. X-ray properties of our sample are obtained from XMM-Newton, Swift and Chandra observations. We unveil the ionized gas outflows in our sample manifested by the non-gravitational b…
An Updated View of the Milky Way from Maser Astrometry
Immer, Katharina; Rygl, Kazi L. J.
Astrometric observations of maser sources in the Milky Way, using the Very Long Baseline Interferometry (VLBI) technique, have been exploited to determine the spiral structure of our Galaxy. Several major spiral arms have now been pinpointed in the first and second Galactic quadrants. Fundamental Galactic parameters such as the distance to the Gal…
The Stationary Electric Field in the Heliosphere and Its Possible Relation to Current Sheets
Kislov, Roman A.
The nature of the large-scale electric field in the heliosphere is discussed in this paper. The electric potential along each line of the magnetic field should be constant in the ideally conductive solar wind. A high electric potential is supposed to be maintained by the rapidly flowing solar wind far from the Sun and, near the Sun, by the unipola…
The Effect of Age on the Grouping of Open Clusters: II—Are There Old Binary Clusters?
Casado, Juan
In the present study, we continue testing the Primordial Group hypothesis (Casado 2022), which postulates that only sufficiently young open clusters can be binary or multiple, and old clusters are essentially single. To this end, we revisit all the remaining binary cluster candidates in the Galaxy having at least one cluster older than 100 Myr thr…
Ulysses Flyby in the Heliosphere: Comparison of the Solar Wind Model with Observational Data
Malova, Helmi V.; Popov, Victor Yu.; Zelenyi, Lev M. +1 more
A model capable of reproducing a set of solar wind parameters along the virtual spacecraft orbit out of an ecliptic plane has been developed. In the framework of a quasi-stationary axisymmetric self-consistent MHD model the spatial distributions of magnetic field and plasma characteristics at distances from 20 to 1200 Solar radii at almost all sol…