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A chemical analysis of seven red giants of the Galactic cluster NGC 4349
Pereira, C. B.; Holanda, N.; Ramos, André A. +2 more
In this study, we undertake a comprehensive investigation of seven red giant stars of NGC 4349 (#005, #009, #079, #127, #168, #174, and #203) and one non-member star (#053). Accurate abundances of 19 chemical species and 12C/13C isotopic ratio are determined using high-signal-to-noise FEROS spectra and standard spectroscopic …
Contribution of Spicules to Solar Coronal Emission
Klimchuk, James A.; Sarkar, Aveek; Sow Mondal, Shanwlee
Recent high-resolution imaging and spectroscopic observations have generated renewed interest in spicules' role in explaining the hot corona. Some studies suggest that some spicules, often classified as type II, may provide significant mass and energy to the corona. Here we use numerical simulations to investigate whether such spicules can produce…
Monitoring accretion rate variability in the Orion Nebula Cluster with the Wendelstein Wide Field Imager
Manara, C. F.; Preibisch, T.; Ercolano, B. +2 more
Context. The understanding of the accretion process has a central role in the understanding of star and planet formation.
Aims: We aim to test how accretion variability influences previous correlation analyses of the relation between X-ray activity and accretion rates, which is important for understanding the evolution of circumstellar disks …
Revealing the dust grain polarization properties as a function of extinction and distance towards NGC 1893
Jose, Jessy; Wang, Jia-Wei; Lai, Shih-Ping +5 more
Dust polarization observations at optical wavelengths help us to understand the dust grain properties and trace the plane-of-the-sky component of the magnetic field. In this study, we make use of the I-band polarization data acquired from AIMPOL along with the distances (d) and extinction (AV) data to study the variation of polarization…
TESS search for substellar companions through pulsation timing of δ Scuti stars. I. Discovery of companions around Chang 134 and V393 Car
Piotto, G.; Nascimbeni, V.; Vaulato, V.
Early-type main-sequence pulsating stars such as δ Scuti variables are one of the least explored class of targets in the search for exoplanets. Pulsation timing (PT) is an alternative technique to the most effective search methods. It exploits the light-travel-time effect (LTTE) to infer the presence of additional massive bodies around a pulsating…
The pre-He white dwarfs in eclipsing binaries - III. WASP 1625-04
Hong, Kyeongsoo; Lee, Jae Woo; Park, Jang-Ho
1SWASP J162545.15-043027.9 (WASP 1625-04) has been announced as one of EL CVn candidates showing total primary eclipses and ellipsoidal variations. This paper presents the absolute properties of the binary star, based on our high-resolution spectroscopy conducted from 2015 through 2020. From the spectral analysis, the radial velocities (RVs) for b…
Constraints on the uncertainty, timing, and magnitude of potential Mars oceans from topographic deformation models
Rivera-Hernández, Frances; Sholes, Steven F.
Proposed ocean paleoshorelines on Mars have faced criticism over their genetic interpretation and because they deviate significantly from an expected equipotential surface (by many kilometers). Multiple geophysical deformation models have been proposed to explain this large topographic range and deviation including true polar wander and direct Tha…
A speckle-imaging search for close and very faint companions to the nearest and brightest Wolf-Rayet stars
Moffat, Anthony F. J.; Howell, Steve B.; Shara, Michael M. +4 more
Gravitationally bound companions to stars enable determinations of their masses, and offer clues to their formation, evolution, and dynamical histories. So motivated, we have carried out a speckle imaging survey of eight of the nearest and brightest Wolf-Rayet (WR) stars to directly measure the frequency of their resolvable companions, and to sear…
Kinematical Analysis of Substructure in the Southern Periphery of the Large Magellanic Cloud
Monachesi, Antonela; Choi, Yumi; Majewski, Steven R. +10 more
We report the first 3D kinematical measurements of 88 stars in the direction of several recently discovered substructures in the southern periphery of the Large Magellanic Cloud (LMC) using a combination of Gaia proper motions and radial velocities from the APOGEE-2 survey. More specifically, we explore stars in assorted APOGEE-2 pointings in a re…
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…