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JWST imaging of the closest globular clusters—I. Possible infrared excess among white dwarfs in NGC 6397
Salaris, M.; Apai, D.; Anderson, J. +9 more
We present James Webb Space Telescope observations of the globular cluster NGC 6397 and use them to extend to infrared wavelengths the characterization of the cluster's entire white dwarf (WD) cooling sequence (CS). The data allows us to probe fundamental astrophysical WD properties and to search for evidence in their colors for (or against) the e…
HST astrometry of the closest brown dwarfs-II. Improved parameters and constraints on a third body
Apai, D.; Pourbaix, D.; Bedin, L. R. +5 more
Located at less than two pc away, Luhman 16 AB (WISE J104915.57-531906.1) is the closest pair of brown dwarfs and the third closest "stellar" system to Earth. An exoplanet candidate in the Luhman 16 binary system was reported in 2017 based on a weak astrometric signature in the analysis of 12 HST epochs. An additional epoch collected in 2018 and r…
Constraining stellar tidal quality factors from planet-induced stellar spin-up
Chiappini, Cristina; Poppenhaeger, Katja; Ilić, Nikoleta +1 more
The dynamical evolution of tight star-planet systems is influenced by tidal interactions between the star and the planet, as was shown recently. The rate at which spins and orbits in such a system evolve depends on the stellar and planetary tidal dissipation efficiency. Here, we present a method to constrain the modified tidal quality factor Q
Spectroscopic and dynamic orbital analyses of metal‑poor and high proper‑motion stars: I. HD 8724 and HD 195633
Bilir, S.; Şahin, T.; Plevne, O. +2 more
In this study, spectral, age, kinematic, and orbital dynamical analyses were conducted on metal‑poor and high proper‑motion (HPM) stars, HD 8724 and HD 195633, selected from the Solar neighborhood. This analysis combines detailed abundance measurements, kinematics, and orbital dynamics to determine their origin. Standard 1D local thermodynamic equ…
Photometric and Kinematic Studies of Open Clusters Ruprecht 1 and Ruprecht 171
Bilir, Selçuk; Yontan, Talar; Banks, Timothy S. +5 more
This study outlines a detailed investigation using CCD UBV and Gaia DR3 data sets of the two open clusters Ruprecht 1 (Rup-1) and Ruprecht 171 (Rup-171). Fundamental astrophysical parameters such as color excesses, photometric metallicities, ages, and isochrone distances were based on UBV-data analyses, whereas membership probability calculations,…
Orbit of the visual binary star 61 Cyg
Izmailov, I. S.; Apetyan, A. A.
We present the orbit and the mass estimates for the components of the visual binary star 61 Cyg obtained with the positional observations, including the high-precision Gaia data, and the measurements of differences in the radial velocities and the radial accelerations of the components. Since the orbital period of this star significantly exceeds t…
Radial Metallicity Gradients for the Chemically Selected Galactic Thin Disc Main-Sequence Stars
Seabroke, G. M.; Bilir, S.; Ak, T. +3 more
We present the radial metallicity gradients within the Galactic thin disc population through main-sequence stars selected on the chemical plane using GALAH DR3 accompanied with Gaia DR3 astrometric data. The [Fe/H], [α/Fe] and [Mg/H] radial gradients are estimated for guiding radius as -0.074±0.006, +0.004±0.002, -0.074±0.006 dex kpc -1…
Updated absolute parameters and kinematics of IS CMa
Alan, Neslihan; Canbay, Remziye; Evcil, Serkan +2 more
Eclipsing binary systems are significant objects for astrophysics in that direct observations can determine the fundamental parameters of stars. In this study, we precisely determined the fundamental parameters of the binary component stars obtained by simultaneous analysis of radial velocities and the TESS light curve using the Wilson and Devinne…
Bright spectroscopic binaries: III. Binary systems with orbital periods of P > 500 days
Jack, Dennis; Schröder, Klaus-Peter; Hernández Huerta, Missael Alejandro +1 more
We present an analysis of nine bright spectroscopic binaries (HD 1585, HD 6613, HD 12390, HD 39923, HD 55201, HD 147430, HD 195543, HD 202699, HD 221643), which have orbital periods of P>500 days. These well-separated binaries are the last stars of our sample that we observed with the TIGRE telescope obtaining intermediate-resolution spectra of…
Gaia23ckh: Symbiotic outburst of the assumed Mira variable V390 Sco
Skowron, Jan; Charbonnel, Stéphane; Garde, Olivier +5 more
The poorly studied variable star V390 Sco, previously classified as a Mira pulsator, was detected in a brightening event by the ESA Gaia satellite in September 2023. This work presents an analysis of available archival multifrequency photometric data of this target, along with our spectroscopic observations. Our findings lead to the conclusion tha…