• SANTOSH JOSHI

Articles written in Journal of Astrophysics and Astronomy

• The Nainital-Cape Survey: A search for variability in Ap and Am stars

The “Nainital-Cape Survey” program for searching photometric variability in chemically peculiar (CP) stars was initiated in 1997 at ARIES, Nainital. We present here the results obtained to date. The Am stars HD 98851, HD 102480, HD 13079 and HD 113878 were discovered to exhibit δ Scuti type variability. Photometric variability was also discovered in HD 13038, for which the type of peculiarity and variability is not fully explained. The null results of this survey are also presented and discussed.

• Asteroseismology of Pulsating Stars

The success of helioseismology is due to its capability of measuring 𝑝-mode oscillations in the Sun. This allows us to extract information on the internal structure and rotation of the Sun from the surface to the core. Similarly, asteroseismology is the study of the internal structure of the stars as derived from stellar oscillations. In this review we highlight the progress in the observational asteroseismology, including some basic theoretical aspects. In particular, we discuss our contributions to asteroseismology through the study of chemically peculiar stars under the 'Nainital-Cape Survey' project being conducted at ARIES, Nainital, since 1999. This survey aims to detect new rapidly-pulsating Ap (roAp) stars in the northern hemisphere. We also discuss the contribution of ARIES towards the asteroseismic study of the compact pulsating variables. We comment on the future prospects of our project in the light of the new optical 3.6-m telescope to be installed at Devasthal (ARIES). Finally, we present a preliminary optical design of the high-speed imaging photometers for this telescope.

• Optical observations of star clusters NGC 1513 and NGC 4147; white dwarf WD 1145$+$017 and K band imaging of star-forming region Sh 2-61 with the 3.6-m Devasthal optical telescope

The UBVRI CCD photometric data of open star cluster NGC 1513 are obtained with the 3.6-m Indo-Belgian Devasthal optical telescope (DOT). Analyses of the GAIA EDR3 astrometric data have identified 106 possible cluster members. The mean proper motion of the cluster is estimated as $\mu_{\alpha}\cos\delta=1.29\pm 0.02$ and $\mu_{\delta}=-3.74\pm0.02$ mas yr$^{-1}$. Estimated values of reddening $E(B-V)$ and distance to the NGC 1513 are $0.65 \pm 0.03$ mag and $1.33 \pm 0.1$ kpc, respectively. Age of $225 \pm 25$ Myr is assigned to the cluster by comparing theoretical isochrones with deeply observed cluster sequences. Using observations taken with the 3.6-m DOT, values of distance and age of the galactic globular cluster NGC 4147 areestimated as $18.2 \pm 0.2$ Kpc and $14 \pm 2$ Gyr, respectively. The optical observations of planetary transit around white dwarf WD $1145\pm 017$ and $K$-band imaging of star-forming region Sharpless Sh 2-61 demonstrate observing capability of 3.6-m DOT. Optical and near-infrared observations of celestial objects and events are being carried out routinely with the 3.6-m DOT. They indicate that the performance of the telescope is at par with those of other similar telescopes located elsewhere in the world. We, therefore, statethat this observing facility augurs well for multi-wavelength astronomy including the study of astrophysical jets.

• # Journal of Astrophysics and Astronomy

Volume 43, 2022
All articles
Continuous Article Publishing mode

• # Continuous Article Publication

Posted on January 27, 2016

Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019