Related papers: C.Ragoonatha Chary and his Variable Stars
Observations from the Heliospheric Imagers (HI-1) on both the STEREO spacecraft have been analysed to search for very long period large amplitude stellar variability, finding 6 new candidates. A total of 85 objects, mostly previously known…
We present a brief review of Chandra X-ray Observatory observations of neutron stars. The outstanding spatial and spectral resolution of this great observatory have allowed for observations of unprecedented clarity and accuracy. Many of…
The Optical Gravitational Lensing Experiment (OGLE) is one of the most productive and influential photometric sky surveys in the history of observational astronomy. Originally designed to detect dark matter through gravitational…
Based on the SIMBAD database, we collected necessary information on the comparison stars used by E. Schenfeld in observations of variable stars in the 19th century.
In this work, we studied the variable stars in the open cluster NGC 1912 based on the photometric observations and $Gaia$ DR2 data. More than 3600 CCD frames in B, V, R filters were reduced, and we obtained the light curves that span about…
This paper is intended to serve two purposes: one, to present an account of the life of Sangamagr\=ama M\=adhava, the founder of the Kerala school of astronomy and mathematics which flourished during the 15th - 18th centuries, based on…
SRC variables are M supergiants, precursors to Type II supernovae, that vary in brightness with moderately regular periods of order 100-1000 days. Although identified as pulsating stars that obey their own period-luminosity relation, few…
Developments of this far-reaching research field are summarized from an observational point of view, mentioning important and interesting phenomena discovered recently by photometry of stellar oscillations of any kind. A special emphasis is…
Abundance analyses are presented and discussed for eight RV Tauri variables. The RV B star UY Ara shows the abundance anomalies seen in other RV B stars, namely elements that condense into grains at high temperature are underabundant but…
Variable stars play a very important role in our understanding of the Milky Way and the universe. In recent years, many survey projects have generated a large amount of photometric data, necessitating classifiers that can quickly identify…
Recent wide-field photometric surveys which target a specific field for long durations are ideal for studying both long and short period stellar variability. Here we report on 75 variable stars detected during observations of a field in…
The Chinese Small Telescope ARray (CSTAR) carried out high-cadence time-series observations of 27 square degrees centered on the South Celestial Pole during the Antarctic winter seasons of 2008, 2009 and 2010. Aperture photometry of the…
We performed R-band time series observations of the young, metal rich open cluster NGC 2301 for 12 nights in Feb. 2004. B images were also obtained and color magnitude diagrams, having limits of R=19.5 and B=21.5, were produced. Only asmall…
The first determination of the surface temperature of stars other than the Sun is due to the Hungarian astrophysicist B\'ela Hark\'anyi. Prompted by the recent unprecedented increase in the availability of stellar temperature estimates from…
We obtained a series of more than two hundred R-band CCD images for the crowded central (115"x77") region of the metal-poor globular cluster M15 with an angular resolution of 0.5"-0.9" in most images. Optimal image subtraction was used to…
Nine new short period variable stars have been discovered in the direction of the open cluster Cr464 in Camelopardalis. The field was observed using Tzec Maun Observatory's telescope AP180. Two new variable stars were classified as…
We report the discovery of three new variable stars in Indus: USNO-B1.0 0311-0760061, USNO-B1.0 0309-0771315, and USNO-B1.0 0315-0775167. Light curves of 3712 stars in a 87' x 58' field centered on the asynchronous polar CD Ind were…
We review the current status of classical Cepheid and RR Lyrae distance scales. We discuss the most recent theoretical and empirical findings together with pros and cons of different methods. The use of Cepheids and RR Lyrae stars as…
Cataclysmic variables are among the photometrically most unstable stars in the zoo of stellar objects, exhibiting light variations on all time-scales between millennia and seconds. The literature is full of reports on variable phenomena…
We developed software for detection of variable stars using CCD photometry. It works with "varfind data" that could be exported after processing CCD frames using C-Munipack. Our goals were maximum automation and support of large fields of…