Search Publications
A Deep Investigation of Two Poorly Studied Open Clusters Haffner 22 and Melotte 71 in the Gaia era
Bisht, D.; Rangwal, Geeta; Yadav, R. K. S. +4 more
This paper presents a deep investigation of two open clusters, Haffner 22 and Melotte 71, using astrometric and photometric data from Gaia EDR3. We identified 382 and 597 most probable cluster members with membership probability higher than 50%. Mean proper motions in R.A. and decl. are estimated as (-1.631 ± 0.009, 2.889 ± 0.008) and (-2.398 ± 0.…
Optical Observations of the Nearby Type Ia Supernova 2021hpr
Zhang, Yu; Zhang, Tianmeng; Wu, Hong +6 more
We present the optical photometric and spectroscopic observations of the nearby Type Ia supernova (SN) 2021hpr. The observations covered the phase of -14.37 to +63.68 days relative to its maximum luminosity in the B band. The evolution of multiband light/color curves of SN 2021hpr is similar to that of normal Type Ia supernovae (SNe Ia) with the e…
Ionization and Star Formation in the Giant H II Region SMC-N66
Kniazev, A.; Hamann, W. -R.; Sabbi, E. +8 more
The NGC 346 young stellar system and associated N66 giant H II region in the Small Magellanic Cloud are the nearest example of a massive star-forming event in a low metallicity (Z ≈ 0.2Z ⊙) galaxy. With an age of ≲3 Myr this system provides a unique opportunity to study relationships between massive stars and their associated H II regio…
Digitization, Measurement, and Analysis of a 1905 Barnard Atlas Photographic Plate
Cerny, William; Kron, Richard G.; Martinez, Michael N. +7 more
In the second paper in this series, we improve on our previous demonstration of the ability of a commercially available graphic arts scanner and cost-effective analysis tools to produce scientifically useful scans of astronomical photographic plates. We describe a method using freely available tools to extract magnitude measurements from the star …
Role of Topocentric Parallax in Near-Earth Object Initial Orbit Determination
Zhai, Chengxing; Shao, Michael; Saini, Navtej S. +5 more
Near-Earth Object (NEO) initial orbit determination typically uses astrometric measurements during a close approach over a time window much shorter than the orbital period of the NEO. The initial orbit is only weakly determined with dominant uncertainties in the distance of the NEO from the Earth. Topocentric astrometric measurements allow us to e…
Interstellar Extinction and Polarization of Stars in the Open Cluster NGC 6709
Topasna, G. A.; Kaltcheva, N. T.; Gibson, S. D.
We present BVRI polarimetric measurements of 23 stars in the direction of the open cluster NGC 6709. Fifteen stars display wavelength-dependence of polarization which is typically due to selective extinction in the interstellar medium and could be fitted to the Serkwoski equation. Based on these stars, we obtained an average maximum degree of pola…
Photometric and Spectroscopic Studies of the Long-Period Low-Mass-Ratio Deep-Contact Binary KN Per
Wang, Xi; Guo, Ya-Ni; Li, Kai +6 more
Photometric analysis and spectroscopic study of the long-period low-mass-ratio deep-contact binary KN Per were performed. The light curves of the BV(RI) c band were from the Ningbo Bureau of Education and Xinjiang Observatory Telescope at the Xingming Observatory. Through the analysis of the Wilson-Devinney program, KN Per was found as…
Astrometric Precision Tests on TESS Data
Lattanzi, M.; Busonero, D.; Bucciarelli, B. +5 more
Astrometry at or below the microarcsec level with an imaging telescope assumes that the uncertainty on the location of an unresolved source can be an arbitrarily small fraction of the detector pixel, given a sufficient photon budget. This paper investigates the geometric limiting precision, in terms of CCD pixel fraction, achieved by a large set o…
Planet Patrol: Vetting Transiting Exoplanet Candidates with Citizen Science
Kostov, Veselin B.; Kuchner, Marc J.; Brande, Jonathan +15 more
NASA's TESS mission yields light curves for tens of millions of stars spread across the entire sky, a data set that will be a challenge to fully exploit without help from citizen scientists. To address this, we launched a new citizen science project, called "Planet Patrol", designed to analyze TESS data on exoplanet and eclipsing binary candidates…
A New Period Determination Method for Periodic Variable Stars
Li, Bin; Li, Xu-Zhi; Zhu, Qing-Feng +4 more
Variable stars play a key role in understanding the Milky Way and the universe. The era of astronomical big data presents new challenges for quick identification of interesting and important variable stars. Accurately estimating the periods is the most important step to distinguish different types of variable stars. Here, we propose a new method o…