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Orbital Elements of visual binary stars with very short arcs: With application to double stars from the 1829 southern double star catalog of James Dunlop

Letchford, Roderick R.; White, Graeme L.; Brown, Carolyn J.

Binary double stars are those whose binding energies are less than zero. Obtaining binary star orbits from short arcs has been a long-standing problem in astrophysics. A method is presented and tested here, which addresses the problem by using space-based astrometry, photometry, and astrophysical data, together with historic measures, to generate …

On the lithium abundance of the visual binary components ξ Boo A ( G8V ) and ξ Boo B ( K5V )

Strassmeier, Klaus G.; Steffen, Matthias

A spectroscopic investigation of the lithium resonance doublet in ξ Boo A and ξ Boo B in terms of both abundance and isotopic ratio is presented. We obtained new R = 130,000 spectra with a signal‑to‑noise ratio (S/N) per pixel of up to 3200 using the 11.8 m LBT and PEPSI. From fits with synthetic line profiles based on 1D‑LTE MARCS model atmospher…

Editor's note: A high-energy view of exoplanets and their environments

Schartel, Norbert

The harsh environment where exoplanets live

Pillitteri, Ignazio

Rectilinear elements of visual optical double stars: With application to the 1829 southern double star catalogue of James Dunlop

Letchford, Roderick R.; White, Graeme L.; Brown, Carolyn J.

The relative Rectilinear motion of optical double stars provides an important clue to the relationship of the components. We provide an objective method of confirming the optical status of double stars, and of obtaining unbiased rectilinear elements solely on data obtained from the HIPPARCOS and Gaia DR2 space missions. We apply this technique to …

Quasars' physical properties study based on the medium-band photometric survey

Kotov, Sergey; Dodonov, Sergey; Grokhovskaya, Aleksandra

The study is about the quasars' cosmological evolution. We used the medium-band photometric survey at the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory. The HS47-22 field with an area of 2.38 square degrees has been selected. We have classified objects and composed a sample of quasars using broadband photometric data and morpholo…

WX Cen is X‑ray quiet: Does this signify a high‑mass or a low‑mass binary?

Zhekov, Svetozar A.

We present results from analysis of the XMM–Newton observation (2021 February) of the enigmatic object WX Cen: a presumed massive Wolf–Rayet (WR) binary, (WN3 + WC4), or a low‑mass binary. WX Cen was not detected in X‑rays. Its UV emission shows periodic variability with a period (0.405–0.434 day) similar to that found in the optical for this obje…

Gaia search for stellar companions of TESS Objects of Interest II

Mugrauer, Markus; Michel, Kai-Uwe

We present the latest results of our ongoing multiplicity study of (Community) TESS Objects of Interest, using astro- and photometric data from the ESA-Gaia mission, to detect stellar companions of these stars and to characterize their properties. In total, 107 binary, 5 hierarchical triple star systems, as well as one quadruple system were detect…

Metal-poor stars observed with the automated planet finder telescope. III. CEMP-no stars are the descendant of population III stars

Zhao, Gang; Mardini, Mohammad K.; Al-Wardat, Mashhoor A. +4 more

This study reports a probabilistic insight into the stellar-mass and supernovae (SNe) explosion energy of five CEMP-no stars' possible progenitors. As such, a direct comparison between the abundance ratios [X/Fe] of the light-elements and the predicted nucleosynthetic yields of SN of high-mass metal-free stars has been performed. This comparison s…

A study of open clusters Frolov 1 and NGC 7510 using CCD UBV photometry and Gaia DR2 astrometry

Bilir, Selçuk; Yontan, Talar; Paunzen, Ernst +6 more

We present reddening, photometric metallicity, age, and distance estimates for the Frolov 1 and NGC 7510 open clusters based on charge‑coupled device (CCD)UBVphotometric andGaiadata. Photometric observations were collected using the 1‑m telescope of the TÜBİTAK National Observatory.Gaiadata release 2 (DR2) proper motion data in the direction of tw…