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Limiting the accretion disc light in two mass transferring hot subdwarf binaries
Mereghetti, Sandro; Piirola, Vilppu; Kupfer, Thomas +6 more
We report the results from follow-up observations of two Roche-lobe filling hot subdwarf binaries with white dwarf companions predicted to have accretion discs. ZTF J213056.71+442046.5 (ZTF J2130) with a 39-min period and ZTF J205515.98+465106.5 (ZTF J2055) with a 56-min period were both discovered as subdwarf binaries with light curves that could…
Photometric study of the overcontact binary V826 Aur
Tobin, R. Wes; Berrington, Robert C.
We present BVRC differential photometry of an eclipsing binary system V826 Aur. A period analysis shows near constant period of 0.36 days across two decades of observation. The best fit models are consistent with a W-type W UMa overcontact binary consisting of a less massive G8 primary star and a more massive K0 secondary star. The mode…
SHARAD observations for layered ejecta deposits formed by late-Amazonian-aged impact craters at low latitudes of Mars
Xiao, Zhiyong; Xu, Rui; Ma, Yizhen +2 more
Frequent changes of the rotational inclination of Mars have driven global transitions of the cryosphere. Although glaciers of water ice may have extended to the equatorial region, current observations of surface deposits at latitudes lower than 30° show relative depletion in hydrogen. Thermal stability models predict that at these low latitudes, a…
A new constraint on HCl abundance at the cloud top of Venus
Sato, Takao M.; Sagawa, Hideo
We provided a new constraint on HCl abundance at the cloud top of Venus by infrared spectroscopy using a cross-dispersed high-resolution echelle spectrograph, iSHELL, mounted on the NASA Infrared Telescope Facility (IRTF). This study investigated the inconsistency in HCl abundance between previous ground-based observations and Venus Express solar …
Nonextensive Behavior of Stellar Rotation in the Galactic Disk Components
da Silva, M. P.; do Nascimento, J. -D.; de Lima, M. M. F. +1 more
The solar neighborhood is a unique stellar astrophysical laboratory formed by a variety of stars from different origins. In particular, two of the most notable populations known are the thick and thin disk stars, each characterized by distinct chemical compositions, ages, kinematics, and origins. Based on Tsallis nonextensive statistics, we invest…
The GeMS/GSAOI Galactic Globular Cluster Survey (G4CS). II. Characterization of 47 Tuc with Bayesian Statistics
Dotter, Aaron; Monty, Stephanie; Puzia, Thomas H. +5 more
We present a photometric analysis of globular cluster 47 Tuc (NGC 104) using near-IR imaging data from the GeMS/GSAOI Galactic Globular Cluster Survey (G4CS), which is in operation at Gemini-South telescope. Our survey is designed to obtain AO-assisted deep imaging with near diffraction-limited spatial resolution of the central fields of Milky Way…
Time-series photometry and multiwavelength characterization of the young stellar cluster Mon R2
Cieza, Lucas A.; Gamen, Roberto; Orcajo, Santiago
Using the Las Cumbres Observatory Global Telescope Network (LCOGT), we have obtained multi-epoch photometry of the young cluster Mon R2. We have monitored over 6000 sources with i-band between 13 and 23 mag within a 26 × 26 arcmin2 field of view. For each star, we collected ~1500 photometric points covering a temporal window of 23 d. Ba…
Does Turbulence along the Coronal Current Sheet Drive Ion Cyclotron Waves?
Telloni, Daniele; Zank, Gary P.; Adhikari, Laxman +32 more
Evidence for the presence of ion cyclotron waves (ICWs), driven by turbulence, at the boundaries of the current sheet is reported in this paper. By exploiting the full potential of the joint observations performed by Parker Solar Probe and the Metis coronagraph on board Solar Orbiter, local measurements of the solar wind can be linked with the lar…
Accretion in the binary system GG Carinae and implications for B[e] supergiants
Kashi, Amit
We simulate the hydrodynamics of the wind flow in the B[e] supergiant binary system GG Carinae and obtain the mass accretion rate on to the secondary and the observed light curve. We find an inhomogeneous Bondi-Hoyle-Lyttleton accretion into a curved accretion tail, and confirm that the accretion rate is modulated along the orbit, with a maximum c…
Study of solar neighborhood open cluster NGC 6475 and 11 possible members B-type stars
Hendy, Y. H. M.; El-Depsey, M. H.; Shokry, Ahmed +2 more
In the present paper, we performed the optical, astrometric and spectroscopic studies for the open star cluster NGC 6475 using Gaia DR3 data. Using the radial density profile, we estimated the radius of the cluster to be equal to 1.44°. It is located at a distance of 279 ± 17 pc and has a service life of 224 ± 26 Myr. The mean proper motions in RA…