Search Publications
High-resolution spectroscopy of the variable hot post-AGB star LS 4331 (IRAS 17381‑1616)
Hubrig, Swetlana; Parthasarathy, Mudumba; Sarkar, Geetanjali +2 more
An analysis of the high-resolution (
A summary of instruments proposed for observing pulsating variables from the Mt. Abu Observatory
Ganesh, Shashikiran; Prajapati, Prachi; Mishra, Anwesh Kumar +3 more
Pulsating variables play a significant role in shaping modern astronomy. Presently it is an exciting era in observational study of variable stars owing to surveys like OGLE and TESS. The vast number of sources being discovered by these surveys is also creating opportunities for 1–2-m class telescopes to provide follow-up observations to characteri…
Stellar substructures in the Galactic disc and halo: Properties, origins, and evolution
Deepak
Spatial, kinematic, and orbital properties, along with ages and chemical compositions of the thin disc, thick disc, and various stellar substructures in the halo, are studied based on data from the LAMOST and Gaia surveys. The star formation in the Galactic thin and thick disc, with peak metallicities of ‑ 0.20 and ‑ 0.45 dex, is found to have pea…
Herschel investigation of cores and filamentary structures in L1251 located in the Cepheus flare
Soam, Archana; Zhang, Guo-Yin; Dewan, Divyansh +3 more
Molecular clouds are the prime locations of star formation. These clouds contain filamentary structures and cores which are crucial in the formation of young stars. In this work, we aim to quantify the physical properties of structural characteristics within the molecular cloud L1251 to better understand the initial conditions for star formation. …
Luminosity dependent cyclotron line in Swift J1626.6‑5156
Paul, Biswajit; Tobrej, Mohammed; Rai, Binay +3 more
We studied the timing and spectral properties of the Be/X-ray pulsar Swift J1626.6‑5156 using the NICER observations of its 2021 outburst. The most important observation is the positive correlation of the centroid energy of the fundamental cyclotron line with the luminosity. This observation agrees with the usual positive correlation of the centro…
Markov Chain Monte Carlo optimization applied to double stars from Miller & Pitman research
Budding, Edwin; Rhodes, Michael D.; Banks, Timothy +1 more
Model orbits have been fitted to 27 physical double stars listed in a 1922 catalog. A Markov Chain Monte Carlo technique was applied to estimate best-fitting values and associated uncertainties for the orbital parameters. Dynamical masses were calculated using parallaxes from the Hipparcos mission and are presented in this paper with the estimates…
Searching for wide binary stars with non-coeval components in the northern sky
Malkov, Oleg; Kniazev, Alexey; Gorda, Stanislav
We have spectroscopically studied the last six stars in the northern sky from our preliminary list of candidates for wide non-coeval pairs, and we have found no evidence of non-coevality. Thus, considering our previous research, which found one such binary system, we confirm that our preliminary estimate of the fraction of binaries in the solar ne…
A detailed study of dwarf galaxies in the core of the Coma Cluster
Hasan, S. N.; Poloji, Nagamani; Hasan, Priya
In an earlier paper, we determined the morphological types of galaxies in the Coma Cluster using data from the HST/ACS Coma Cluster treasury survey. Of the 132 members, 51 are non-dwarfs and 81 are dwarfs. We define dwarfs to have an absolute luminosity
Possibilities of identifying members from Milky Way satellite galaxies using unsupervised machine learning algorithms
Sivarani, Thirupathi; Divakar, Devika K.; Doddamani, Vijayakumar H. +1 more
A detailed study of stellar populations in Milky Way (MW) satellite galaxies remains an observational challenge due to their faintness and fewer spectroscopically confirmed member stars. We use unsupervised machine learning methods to identify new members for nine nearby MW satellite galaxies using Gaia data release-3 (Gaia DR3) astrometry, the Da…