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Different manifestations of a loop-like transient brightening in solar atmospheres
Wang, Jincheng; Cai, Qiangwei; Feng, Hengqiang +1 more
Context. Small-scale transient brightenings that are the consequence of magnetic reconnection play pivotal roles in the heating process of solar atmospheres. These phenomena contain key information about the dynamic evolution of the solar magnetic field. The fine-scale structures triggered by instabilities in these brightenings are intimately conn…
GBT/Argus Observations of Molecular Gas in the Inner Regions of IC 342
Bolatto, Alberto D.; Leroy, Adam K.; Rosolowsky, Erik +9 more
We report observations of the ground state transitions of 12CO, 13CO, C18O, HCN, and HCO+ at 88–115 GHz in the inner region of the nearby galaxy IC 342. These data were obtained with the 16 pixel spectroscopic focal plane array Argus on the 100 m Robert C. Byrd Green Bank Telescope (GBT) at 6″–9″ resolut…
Structural control on formation of polygonal rims of impact craters in Thaumasia Minor, Mars
Dasgupta, Dipayan; Kundu, Abhik; Dasgupta, Nilanjan +3 more
It has been known for almost a century that the surfaces of rocky planets contain polygonal-shaped, circular, or elliptical craters. Researchers have hypothesized that pre-existing structurally weak planes, such as faults or fractures, in the vicinity of the impact, are responsible for polygonal patterns of the crater rims. Thaumasia Minor, Mars, …
Chemical abundances of 20 barium stars from the OHP spectra
Shi, Jianrong; Zhao, Gang; Zhao, Jingkun +7 more
Based on the high resolution and high signal-to-noise spectra, we derived the chemical abundances of 20 elements for 20 barium (Ba-) stars. For the first time, the detailed abundances of four sample stars, namely HD 92482, HD 150430, HD 151101, and HD 177304 have been analysed. Additionally, Ba element abundance has been measured using high-resolu…
X-Rays from the Nearby Compact Emission-line Galaxy NGC 2366
Kaaret, Philip; Prestwich, Andrea
Luminous, compact emission-line galaxies (LCGs) are the most abundant class of confirmed Lyman continuum (LyC) emitters. An optical integral field study of the nearby LCG NGC 2366 reveals an outflow originating at the star cluster "knot B" thought to clear a channel via mechanical feedback that enables LyC escape. We observed NGC 2366 with the Cha…
Observational constraints on modified CPL models considering non-cold dark matter
Sardar, Gopal; Chakraborty, Subenoy
In the present work we consider three modified Chevallier–Polarski–Linder (CPL) models with considering non-cold dark matter in the background of homogeneous and isotropic FLRW space–time model. From the observational data set ((Pantheon+)+BAO+HST) we find that all the parameters involved in the models having equation of dark energy state ωde=ω0+ω…
Long Term CCD Photometry of the Distant Cluster NGC2419: The CMD Revisited
Arellano Ferro, A.; Muneer, S.; Yepez, M. A. +4 more
Employing VI images of NGC 2419 acquired over 17 years, light curves for most of the known variables in the field of the cluster are produced. A cluster membership analysis for about 3100 stars in the cluster field with proper motions from Gaia-DR3 revealed the presence of member stars as far as 140 pc from the cluster center and enabled the const…
A Photometric and Astrometric Study of Open Star Clusters FSR-163 and Majaess 215 Using Gaia DR3
Tadross, A. L.; Ali, Ola; Osman, A. I. +1 more
We have examined most of the astrophysical properties of the two star clusters, FSR-163 and Majaess 215, using the third data release of the Gaia space mission (Gaia DR3). We utilized the pyUPMASK method to allocate the probabilities of stars' membership candidates. Using the clusters' trigonometric parallaxes of the members with probabilities P &…
Searching for wide binary stars with non-coeval components in the northern sky
Malkov, Oleg; Kniazev, Alexey; Gorda, Stanislav
We have spectroscopically studied the last six stars in the northern sky from our preliminary list of candidates for wide non-coeval pairs, and we have found no evidence of non-coevality. Thus, considering our previous research, which found one such binary system, we confirm that our preliminary estimate of the fraction of binaries in the solar ne…
Revisiting Physical Parameters of the Benchmark Brown Dwarf LHS 6343 C through a Hubble Space Telescope/WFC3 Secondary-eclipse Observation
Montet, Benjamin T.; Gagné, Jonathan; Albert, Loïc +7 more
The LHS 6343 system consists of a resolved M-dwarf binary with an evolved, negligibly irradiated brown dwarf (BD), LHS 6343 C, orbiting the primary star. Such BD eclipsing binaries present rare and unique opportunities to calibrate substellar evolutionary and atmosphere models since mass, radius, temperature, and luminosity can be directly measure…