In this work, we present improved scaling relations for globular cluster systems (GCS) and examine how type, elliptic shape (epsilon), systemic velocity (V-sys), Sersic index (n), dynamic index (R-e & times; sigma), light profile slope (alpha, gamma) and age affect the number of globular clusters (NGCs). To get a better understanding of the formation and development mechanisms of globular clusters, we separate the influence of the structural and dynamic parameter using several source data from SLUGGS, ACSVCS, and Forbes et al. (2018). Our findings support the presence of a precise co-evolution scenario where the halo's age, shape, and depth all have distinct effects on globular cluster abundance.
We present a collection of eclipse timings of eclipsing binary stars obtained over the extended time interval 2014-2024. In all observations, a DSLR camera was used as the detector. The presented dataset contains 250 previously unpublished minima of 86 eclipsing binary systems obtained at three observing sites. The minima were determined from calibrated light curves using the phenomenological modelling approach, and their uncertainties were estimated by bootstrap resampling. The presented measurements extend the available timing coverage of the observed systems and may contribute to future studies of orbital period variations and other long-term phenomena in eclipsing binaries.
We revisit three published high-velocity-star catalogues drawn from Gaia and LAMOST-Li et al. (2021, 591 stars), Li et al. (2023, 88 stars) and Liao et al. (2024, 519 stars)-and quantify how the published unbound classification of these candidates changes with the choice of distance estimator and with the choice of radial-velocity catalogue. After Gaia DR3 source id resolution and de-duplication our master sample contains 1101 unique stars. 675 of them satisfy ruwe < 1.4, Pi/sigma(Pi) > 5 and carry a Gaia DR3 radial velocity (the Gaia-only clean sample). 356 additionally pass a 1 arcsec LAMOST DR9 LRS cross-match, atmospheric-parameter cuts and a 50 km s(-1) Gaia-LAMOST RV agreement test (the final-strict sample). For every star in this strict subset, the three-dimensional Galactocentric rest-frame speed v (grf) and the local escape speed v(esc) are computed with a 1000-draw Monte Carlo under the MWPoTENTiAL2014 potential of Bovy (2015), once with inverse-parallax distances (1000/Pi ) and once with the geometric distances of Bailer-Jones et al. (2021). Switching from inverse parallax to Bailer-Jones distances on the same 356 stars reduces the count with P (unbound)=P ( v(grf) > v(esc) ) > 0.5 from 48 to 3, and the count with P unbound > 0.9 from 12 to 1 ; 45 stars are downgraded across the P-unbound=0.5 threshold and none are gained. Substituting LAMOST radial velocities for Gaia radial velocities on the same subset changes the median v(grf) by 0.00 km s(-1) ( p(90) Delta v(grf)=5.7 km s(-1) ) and flips the P-unbound=0.5 classification of one star out of 356. The unbound classification of these published candidates is therefore set by the distance estimator, not by the choice of radial-velocity catalogue. The final-strict sample, a Top-15 main candidate table, and a Top-30 machine-readable supplementary CSV are released with this paper; the three highest-confidence candidates are metal-poor giants that warrant targeted spectroscopic follow-up.
In this study, we present a comprehensive photometric and physical characterization of the main-belt asteroid (300) Geraldina. Our analysis includes determining its sidereal rotational period, shape modeling, spin-axis orientation, as well as dynamical and spectral properties. The investigation is based on two decades of archival photometry from the Bulgarian National Astronomical Observatory (BNAO) Rozhen, complemented by dense CCD lightcurve observations obtained since 2017 at the Astronomical Station Vidojevica (ASV), dense data from ALCDEF, and augmented with sparse-in-time measurements from Gaia Data Release 3 (DR3). By combining these heterogeneous datasets within and using the lightcurve inversion method, we confirmed the asteroid's prograde sense of rotation and obtained two symmetrically mirrored pole solutions for the asteroid model. Our dynamical studies show that (300) Geraldina remains stable in 100 Myr. Although close to the 2:1 mean-motion resonance with Jupiter, it is not captured into it during the observed time. Instead, it exhibits interactions with an unidentified high-order mean-motion resonance, which appears to contribute to its long-term stability. Its spectral type (C) with a primitive carbonaceous composition, in combination with low albedo and long-term stability, is consistent with the assumption that (300) Geraldina is an ancient asteroid.
This study explores photometric variability in a sample of hot stars in order to test whether variability arises from rotational modulation due to surface temperature spots. Frequencies determined from the projected rotational velocities were compared with frequencies estimated on the basis of TESS light curves. In all five cases, the spectroscopic frequency was lower than the photometric one preserving possibility that the observed brightness variations can be rotationally induced. In two of our targets, HT Cet and HD 219487, the phoOur results suggest that spot activity inducing rotational modulation may exist in stars hotter than 6500 K, highlighting the value of combined spectroscopic and photometric analysis of variations.
