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Dampening long-period doppler shift oscillations using deep machine learning techniques in the solar network and internetwork
Tavabi, Ehsan; Sadeghi, Rayhaneh
This study aimed to explore the Doppler shift at different wavelengths in the IRIS solar spectrum and analyze the evolution and statistical properties of longitudinal oscillations with damping in chromosphere and transition region bright points (BPs). Understanding the damping mechanism and statistical properties of oscillations in BPs is crucial …
How Does the Structure of Rarefaction Regions Develop?
Němeček, Zdeněk; Ďurovcová, Tereza; Šafránková, Jana
A rarefaction region (RR) occurs at the trailing edge of the fast solar wind stream. It comes from an area of small longitudinal extent on the solar surface and exhibits a fine and complex structure. In our study, we did a superposed epoch analysis of the proton and α parameters across the RR and observed their gradual evolution. We did not find a…
Comparison of Solar Multifrequency Microwave Data with Other Solar Indices for Understanding Solar and Stellar Microwave Data
Namekata, Kosuke; Shimojo, Masumi; Watanabe, Kyoko +2 more
Thermal microwave emissions detected from stellar atmospheres contain information on stellar activity. However, even for the Sun, the relationship between multifrequency microwave data and other activity indices remains unclear. We investigated the relationships among the thermal microwave fluxes with 1, 2, 3.75, and 9.4 GHz, their circular polari…
Long-term Speckle Interferometric Monitoring of Binary Systems: 2007–2023 Positional Measurements and Orbits of Seven Objects
Mitrofanova, Arina; Dyachenko, Vladimir; Beskakotov, Anatoly +3 more
The results of seventeen years of speckle interferometric monitoring of seven objects (Chara 122Aa, GJ 3010, HIP 1987, GJ 3076, HIP 11253, HIP 11352, and HIP 14929) are presented. Observational data were obtained at the 6 m Big Telescope Alt-azimuthal Special Astrophysical Observatory of the Russian Academy of Science (BTA SAO RAS) from 2007 to th…
Discovery of Radial Spectral Hardening in the Hot Bubble of Planetary Nebula BD+30°3639 with Median Energy Imaging
Montez, Rodolfo
We apply an imaging analysis technique to study the spatial distribution of the X-ray spectral hardness across the hot bubble of planetary nebula BD+30°3639. Hot bubble emission is typically photon starved, thus limiting the methods for spatial–spectral analysis; however, this technique uses the statistics of photon energies across the nebula to i…
ExoplANETS-A: A virtual observatory database for host stars and planetary systems. The effect of XUV on planet atmospheres
Huélamo, N.; García, R. A.; Solano, E. +12 more
Context. ExoplANETS-A is an EU Horizon-2020 project with the primary objective of establishing new knowledge on exoplanet atmospheres. Intimately related to this topic is the study of the host stars' radiative properties in order to understand the environment in which exoplanets lie.
Aims: The aim of this work is to exploit archived data from…
An Efficient Method for Batch Derivation of Detached Eclipsing Binary Parameters: Analysis of 34,907 OGLE Systems
Liu, Wei; Ding, Xu; Ji, KaiFan +3 more
Detached eclipsing binary (EB) systems are crucial for measuring the physical properties of stars that evolve independently. Large-scale time-domain surveys have released a substantial number of light curves for detached EBs. Utilizing the Physics of Eclipsing Binaries package in conjunction with Markov Chain Monte Carlo (MCMC) methods for batch p…
Forgotten treasures in the HST/FOC UV imaging polarimetric archives of active galactic nuclei: II. Mrk 463E
Lopez-Rodriguez, E.; Marin, F.; Barnouin, T.
Context. The Mrk 463 system is known to host two powerful sources that are separated by about 4 kpc, which were both identified as active galactic nuclei (AGN). This makes the Mrk 463 system a unique laboratory for studying the geometry and dynamics of galaxy merging and its relation to AGN duty cycles. Aims. The eastern nucleus, Mrk 463E, is the …
Mass-transfer Outbursts Reborn: Modeling the Light Curve of the Dwarf Nova EX Draconis
Baptista, Raymundo; Schlindwein, Wagner
EX Draconis is an eclipsing dwarf nova that shows outbursts with moderate amplitude (≃2 mag) and a recurrence timescale of ≃20–30 days. Dwarf novae outbursts are explained in terms of either a thermal-viscous instability in the disc or an instability in the mass-transfer rate of the donor star (MTIM). We developed simulations of the response of ac…
Low-mass Stellar and Substellar Candidate Companions around Massive Stars in Sco OB1 and M17
Sana, Hugues; Mahy, Laurent; Reggiani, Maddalena +1 more
Massive stars are recognized for their high degree of multiplicity, yet the mass ratio regime below 0.1 remains insufficiently explored. It is therefore unknown whether extremely low-mass (possibly substellar) companions can form and survive in the direct UV-irradiated environment of massive stars. In this paper, we discuss Very Large Telescope/Sp…