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Spectroscopic and Photometric Study of the Eclipsing Binary Star sigma Aquilae
Quadri, U.; Strabla, L.; Franco, L.
We report on spectroscopic and photometric observations of the eclipsing binary star sigma Aquilae (44 Aql). Archival TESS and Hipparcos data are used to confirm the orbital period of 1.95028 ± 0.00002 days, consistent with previous measurements. Doppler shifts of the He I line at 4922 Angstroms from high-resolution spectroscopic data were used to…
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.…
The First BVRcIc Precision Observations and Preliminary Photometric Analysis of the Near Contact TYC 1488-693-1
Caton, D. B.; Hill, R.; Samec, R. G. +1 more
TYC 1488-693-1 is an ~F2 type (T ~6750 K) eclipsing binary. It was observed in April and May 2015 at Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University. Six times of minimum light were determined from our present observations, which include two primary eclipses and four secondary eclipses. In addition,…
I-band Measurements of Red Giant Variables: Methods and Photometry of 66 Stars
Moon, T. T.
New measurements of IC and V-IC are presented for 66 bright red giant variables. This is the first stage of a program to measure sufficient numbers of such stars that also have well-determined Hipparcos parallaxes with a view to calibrating the TRGB in the IC band as a tool for accurately measuring distances to nearby galaxies.
A Demonstration of Accurate Wide-field V-band Photometry Using a Consumer-grade DSLR Camera
Maravelias, G.; Eggenstein, H. -B.; Kloppenborg, B. K. +2 more
The authors examined the suitability of using a Digital Single Lens Reflex (DSLR) camera for stellar photometry and, in particular, investigated wide field exposures made with minimal equipment for analysis of bright variable stars. A magnitude-limited sample of stars was evaluated exhibiting a wide range of (B-V) colors taken from four fields bet…
The Pulsational Behavior of the High Amplitude d Scuti Star RS Gruis
García, J.
RS Gruis is a high-amplitude delta Scuti-type variable star with a mean amplitude of almost half a magnitude in V and a period of almost 3.5 hours. The most recent study of this star by Derekas et al. (2009) suggests the presence of a low-mass dwarf star companion close to the variable star with a period of 11.5 days. Rodriguez et al. (1995) have …
Stellar Photometry With DSLR: Benchmark of Two Color Correction Techniques Toward Johnson's VJ and Tycho VT
Pieri, R.
DSLRs are now routinely used for measuring the V magnitude of stars through their G channel output. This requires a transformation to Johnson V, using a correction based on the catalogue (B-V) color indices of the stars. This paper reviews the responses of the involved passbands and proposes an alternate solution using a synthetic filter made by c…
The History of Variable Stars: A Fresh Look
Hatch, R. A.
(Abstract only) For historians of astronomy, variable stars are important for a simple reason - stars change. But good evidence suggests this is a very modern idea. Over the millennia, our species has viewed stars as eternal and unchanging, forever fixed in time and space - indeed, the Celestial Dance was a celebration of order, reason, and stabil…
Deep Infrared ZAMS Fits to Benchmark Open Clusters Hosting Delta Scuti Stars
Turner, D. G.; Majaess, D. J.; Lane, D. J. +1 more
This research aims to secure precise distances for cluster δ Scuti stars in order to investigate their properties via a VI Wesenheit framework. Deep JHKs color-color and zero-age main sequence (ZAMS) relations derived from ~700 unreddened stars featuring 2MASS photometry and precise Hipparcos parallaxes (d≤25 pc) are applied to establish distances…
Anchoring the Universal Distance Scale Via a Wesenheit Template
Henden, A. A.; Turner, D. G.; Majaess, D. J. +2 more
A VI Wesenheit diagram featuring SX Phoenicis, δ Scuti, RR Lyrae, and type II and classical Cepheid variables is calibrated by means of geometric-based distances inferred from HST, Hipparcos, and VLBA observations (n = 30). The distance to a target population follows from the offset between the observed Wesenheit magnitudes and the calibrated temp…