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V725 Sagittarii: Unique, Important, Neglected
Percy, J. R.
During the last century, V725 Sgr gradually changed from a 12-day Cepheid to an 85-day yellow semiregular giant. This paper presents wavelet analysis of AAVSO visual observations from 1982 to 2020, and Fourier analysis of ASAS-SN observations from 2016 to 2018. The results confirm that the previously-identified pulsation period has increased from …
The Reclassification of NSV 1586 from a Suspected Cepheid Star to a UG Class System
Hills, K.; Brincat, S. M.; Galdies, C. +1 more
On 2018 August 9, a contribution to the VSNET mailing list suggested that due to certain photometric attributes, NSV 1586 could possibly belong to the Dwarf Nova (DN) class. Hence, the initial classification of this star as a Cepheid variable star was put into question. This prompted the authors to investigate NSV 1586 in detail. The data obtained…
Observation of Gaia (DR2) Red and White Dwarf Binary Stars in the Solar Neighborhood (Abstract)
Wasson, R.
(Abstract only) The Gaia satellite combines astrometric, parallax, photometric, and spectroscopic measurements of stellar propertiesówith greater accuracy than ever before. In 2018 Gaia Data Release 2 (DR2) made preliminary but consistent data available for an extraordinary number of stars: 1.3 Billion!
SZ Sculptoris: Light Curve Analyses and Period Study of the Totally Eclipsing, Galactic South Pole, Solar-Type Binary
Hill, R.; Van Hamme, W.; Samec, R. G.
We report here on the first precision BVRI observations, analysis and period study of SZ Sculptoris (GSC 6990-0597), a solar type (T ~ 5040 K), shallow contact, eclipsing binary. It was observed on 2019 October 05 and 2019 November 05 and 07 in remote mode with the Cerro Tololo InterAmerican Observatory 0.6-m SARA South reflector by R. Samec and R…
HD 121620: A Previously Unreported Variable Star with Unusual Properties
Axelsen, R. A.
During a study of the delta Scuti star V1393 Centauri by digital single lens reflex photometry, it was found that two of the chosen comparison stars were variable. This paper reports the subsequent investigation of one of them, HD 121620, which revealed irregular light variations of 0.8 magnitude in V within a time frame of approximately 24 hours.…
Analysis of HAT-P-23 b, Qatar-1 b, WASP-2 b, and WASP-33 b with an Optimized EXOplanet Transit Interpretation Code (Abstract)
Nair, S.; Varghese, J.; Tock, K. +1 more
(Abstract only) The ability for citizen scientists to analyze image data and search for exoplanets using images from small telescopes has the potential to greatly accelerate the search for exoplanets. Recent work on the Exoplanet Transit Interpretation Code (EXOTIC) enables the generation of high-quality light curves of exoplanet transits given su…
CCD Photometry, Light Curve Modeling, and Period Study of the Overcontact Binary Systems V647 Virginis and V948 Monocerotis
Alton, K. B.
Prior to this investigation, monochromatic CCD data for V647 Vir and V948 Mon had only been generated from automated surveys which employ sparse sampling strategies. In this study precise multi-color (B, V, and Ic) light curve data for V647 Vir (2018) and V948 Mon (2017-2018) were acquired at Desert Bloom Observatory (DBO). Both targets…
CCD Photometry, Light Curve Deconvolution, Period Analysis, Kinematics, and Evolutionary Status of the HADS Variable V460 Andromedae
Alton, K. B.; Stepien, K.
Multi-color (BVIc) CCD-derived photometric data were acquired from V460 And, an intrinsic variable classically defined as a High Amplitude delta Scuti (HADS) type system. Deconvolution of precise time-series light curve data was accomplished using discrete Fourier transformation and revealed a fundamental mode (f0) of oscillation at 13.336 d-1 alo…
A Photometric Study of the Contact Binary V384 Serpentis
Michaels, E. J.; Lanning, C. M.; Self, S. N.
In this paper we present the first photometric light curves in the Sloan g', r', and i' passbands for the contact binary V384 Ser. Photometric solutions were obtained using the Wilson-Devinney program which revealed the star to be a W-type system with a mass ratio of q = 2.65 and a f = 36% degree of contact. The less massive component was found to…
SSA Analysis and Significance Tests for Periodicity in S, RS, SU, AD, BU, KK, and PR Persei
Chaplin, G. B.
Visual observations made by experienced observers are adjusted for individual observer bias. We examine the time series using signal processing methods to identify periodicities and test for the significance of the results finding a reliable periods in S Per, and to a limited extent in RS, SU, BU, and KK Per. Recommendations for future visual and …