scholarly journals Photometric Observations of the η Carinae 2009.0 Spectroscopic Event

2010 ◽  
Vol 27 (3) ◽  
pp. 374-377
Author(s):  
H. Landes ◽  
M. Fitzgerald
Keyword(s):  
Binary System ◽  
Star System ◽  
Standard Star ◽  
Previous Event ◽  
Photometric Observations ◽  
Local Comparison ◽  
Comparison Stars ◽  
E Region

AbstractWe have observed η Carinae over 34 nights between 2009 January 4 and 2009 March 27 covering the estimated timeframe for a predicted spectroscopic event related to a suspected binary system concealed within the homunculus nebula. A photometric minimum feature was confirmed to be periodic and comparison to a previous event indicated that the period to within our error was 2022.6±1.0 d. Using the E-region standard star system, the apparent V magnitudes determined for the local comparison stars were HD 303308 8.14±0.02, HD 93205 7.77±0.03, and HD 93162 8.22±0.05. The latter star was found to be dimmer than previously reported.

scholarly journals Long-Term Coudé Radial-Velocity Studies With a 1.2-m Telescope

2001 ◽  
Vol 183 ◽  
pp. 283-288
Author(s):  
C.D. Scarfe
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Star System ◽  
Standard Star ◽  
Stellar Spectra ◽  
Multiple Stars ◽  
Binary And Multiple Stars ◽  
Selection Of

AbstractI have used the 1.2-m telescope and coudé spectrograph of the Dominion Astrophysical Observatory for more than 30 years in a program of radial-velocity observations of binary stars. The program was begun with photographic plates as detectors, but for 20 years the primary detector has been the radial-velocity scanner, which cross-correlates stellar spectra with an artificial mask.Since some of the binaries under observation have periods of several years, the instrument’s stability is an important consideration. I have therefore been obliged to observe standard stars and asteroids to check its performance. These observations are of relevance to efforts to improve the IAU standard star system.I will describe the telescope, spectrograph and scanner, and will briefly discuss some of the results obtained for a selection of binary and multiple stars.

scholarly journals The Symbiotic Binary System AG Pegasi

1980 ◽  
Vol 88 ◽  
pp. 535-542 ◽  
Author(s):  
Charles D. Keyes ◽  
Mirek J. Plavec
Keyword(s):  
Binary System ◽  
Emission Lines ◽  
Complete Coverage ◽  
Cool Component ◽  
Relative Contribution ◽  
Photometric Observations

A complete coverage of the spectrum of AG Peg has been obtained between wavelengths 1200 − 7000 A by us, and can be supplemented by IR photometric observations by others. Our IUE observations yield a lower value of E(B-V), about 0.12. The two stellar components are easily recognized, but their characteristics are still rather uncertain.The cool component may be a normal M1.7 III giant, but the temperature and luminosity of the hot star remain largely indeterminate. Firstly, there are no good models for a hot subdwarf, and secondly, it is difficult to determine the relative contribution of the star itself and the surrounding hydrogen cloud.The emission lines observed in the UV have double or triple structure, indicating two or three distinct emitting regions.

scholarly journals A Long-Duration Pre-flare Dip in the Light Curve of V1054 Oph

1995 ◽  
Vol 151 ◽  
pp. 108-109
Author(s):  
R. Ventura ◽  
I. Pagano ◽  
G. Peres ◽  
M. Rodonò
Keyword(s):  
Spectral Band ◽  
Comparison Star ◽  
Low Intensity ◽  
Photon Count ◽  
Long Duration ◽  
Photometric Observations ◽  
Comparison Stars ◽  
Twin Beam ◽  
Cassegrain Telescope ◽  
Low Amplitude

Photometric observations of V1054 Oph (Wolf 630 AB, mv = 9.69) and of the comparison star HD 152678 (mv = 8.1) were carried out in the UBV bands at Catania Astrophysical Observatory on 1994, June 15, using the 91 cm Cassegrain telescope equipped with an improved version of the twin-beam photometer URSULA (De Biase et al. 1988). We have detected a relatively low-intensity flare event preceded by a pre-flare dip of low amplitude and the exceptionally long duration of 36 min. The integration times were 10, 5 and 5 sec in the U, B and V bands, respectively. The variable and the comparison stars were observed simultaneously in the two independent channels of the twin-beam photometer. The sky background was subtracted from the photon count rates of V1054 Oph and its comparison star in each spectral band, and the flux of the variable was normalized to that of the comparison star.

Photometric observations of the binary system V350 Lacertae

1992 ◽  
Vol 188 (1) ◽  
pp. 151-158
Author(s):  
O. Demircan ◽  
E. Derman ◽  
G. Kahraman
Keyword(s):  
Binary System ◽  
Photometric Observations

scholarly journals Kepler Object of Interest Network

2018 ◽  
Vol 615 ◽  
pp. A79 ◽  
Author(s):  
C. von Essen ◽  
A. Ofir ◽  
S. Dreizler ◽  
E. Agol ◽  
J. Freudenthal ◽  
...  
Keyword(s):  
Star System ◽  
Transiting Planets ◽  
Photometric Observations ◽  
First Results ◽  
Depth Study ◽  
Interesting Candidate ◽  
Site Network ◽  
The Masses ◽  
Long Timescales

During its four years of photometric observations, the Kepler space telescope detected thousands of exoplanets and exoplanet candidates. One of Kepler’s greatest heritages has been the confirmation and characterization of hundreds of multi-planet systems via transit timing variations (TTVs). However, there are many interesting candidate systems displaying TTVs on such long timescales that the existing Kepler observations are of insufficient length to confirm and characterize them by means of this technique. To continue with Kepler’s unique work, we have organized the “Kepler Object of Interest Network” (KOINet), a multi-site network formed of several telescopes located throughout America, Europe, and Asia. The goals of KOINet are to complete the TTV curves of systems where Kepler did not cover the interaction timescales well, to dynamically prove that some candidates are true planets (or not), to dynamically measure the masses and bulk densities of some planets, to find evidence for non-transiting planets in some of the systems, to extend Kepler’s baseline adding new data with the main purpose of improving current models of TTVs, and to build a platform that can observe almost anywhere on the northern hemisphere, at almost any time. KOINet has been operational since March 2014. Here we show some promising first results obtained from analyzing seven primary transits of KOI-0410.01, KOI-0525.01, KOI-0760.01, and KOI-0902.01, in addition to the Kepler data acquired during the first and second observing seasons of KOINet. While carefully choosing the targets we set demanding constraints on timing precision (at least 1 min) and photometric precision (as good as one part per thousand) that were achieved by means of our observing strategies and data analysis techniques. For KOI-0410.01, new transit data revealed a turnover of its TTVs. We carried out an in-depth study of the system, which is identified in the NASA Data Validation Report as a false positive. Among others, we investigated a gravitationally bound hierarchical triple star system and a planet–star system. While the simultaneous transit fitting of ground- andspace-based data allowed for a planet solution, we could not fully reject the three-star scenario. New data, already scheduled in the upcoming 2018 observing season, will set tighter constraints on the nature of the system.

scholarly journals PHOTOMETRIC OBSERVATIONS OF THE CONTACT BINARY SYSTEM V523 CASSIOPEIAE

2006 ◽  
Vol 23 (3) ◽  
pp. 177-188 ◽  
Author(s):  
Jang-Hae Jeong ◽  
Chun-Hwey Kim ◽  
Yong-Sam Lee
Keyword(s):  
Binary System ◽  
Photometric Observations ◽  
Contact Binary

scholarly journals Nova V1500 Cyg - Photometry and Period Variations Study

1977 ◽  
Vol 42 ◽  
pp. 194-200
Author(s):  
I. Semeniuk ◽  
A. Kruszewski ◽  
A. Schwarzenberg-Czerny ◽  
T. Chlebowski
Keyword(s):  
Single Channel ◽  
Brightness Variation ◽  
Emission Lines ◽  
V Band ◽  
Photometric Observations ◽  
Period Variations ◽  
Comparison Stars

This study aims to present our photometric observations of Nova Cygni V1500 1975, and to discuss the period changes of brightness variation on the basis of all available data.The Nova was observed from 2 September 1975 to 26 October 1976 using the single channel UBV photometer attached to the 60-cm reflector of the Ostrowik station of Warsaw University Observatory. The brightness of the Nova decreased considerably during that time and it was necessary to use a sequence of four comparison stars. The variable was usually monitored in the V filter and occasionally measured with B and U filters. The V band is not well suited for observing novae in the nebular stage, since the dominant light contribution comes from O III emission lines.

scholarly journals The Variable Shell Star HR 5999

1977 ◽  
Vol 42 ◽  
pp. 137-143
Author(s):  
P.S. Thé ◽  
H.R.E. Tjin A Djie
Keyword(s):  
Spectral Type ◽  
Proper Motion ◽  
Main Sequence ◽  
Angular Separation ◽  
Double Star ◽  
Star System ◽  
Spectroscopic Observations ◽  
Photometric Observations ◽  
Shell Star ◽  
Hydrogen Lines

From spectroscopic observations Bessell and Eggen (1972) (hereafter called BE) have detected that HR 5999 (erroneously named HR 6000 by BE) is a shell star of spectral type A7 III-IV with hydrogen lines in emission. Photometric observations show subsequently that HR 5999 varies in brightness up to about 1 mag semiregularly with a period of about 1 month. Eggen (1975) believes that HR 5999 forms a pre-main sequence object.With HR 6000, the star HR 5999 forms a visual double star system named Δ199; HR 5999 is the southern component. The angular separation is about 45”. BE show that these stars have a common proper motion, and are, therefore, believed to form a physical pair.

scholarly journals The Symbiotic Binary System EG Andromedae

1987 ◽  
Vol 93 ◽  
pp. 755-758
Author(s):  
D. Chochol ◽  
A. Skopal ◽  
A. Vittone ◽  
A. Mammano
Keyword(s):  
Binary System ◽  
Symbiotic Star ◽  
Line Profiles ◽  
Primary Minimum ◽  
Photometric Observations ◽  
New Period ◽  
Balmer Lines ◽  
The New Period

AbstractPhotometric observations of the symbiotic star EG and confirm that the binary system is eclipsing. The epoch of primary minimum is computed. The new period 474 days instead of 470 days is estimated by a comparison of line profiles of Balmer lines taken in 1967–69 and 1982–84. The new ephemeris is

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