scholarly journals Mid-Cycle Observations of CR Boo and Estimation of the System’s Parameters

Data ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 113
Author(s):  
Daniela Boneva ◽  
Svetlana Boeva ◽  
Yanko Nikolov ◽  
Zorica Cvetković ◽  
Radoslav Zamanov
Keyword(s):  
Binary System ◽  
Observational Data ◽  
Orbital Period ◽  
Binary Star ◽  
Contact Point ◽  
Bright Spot ◽  
V Band ◽  
Phase Rotation

We present observations (with NAO Rozhen and AS Vidojevica telescopes) of the AM Canum Venaticorum (AM CVn) binary star CR Bootis (CR Boo) in the UBV bands. The data were obtained in two nights in July 2019, when the V band brightness was in the range of 16.1–17.0 mag. In both nights, a variability for a period of 25 ± 1 min and amplitude of about 0.2 magnitudes was visible. These brightness variations are most likely indications of “humps”. During our observational time, they appear for a period similar to the CR Boo orbital period. A possible reason of their origin is the phase rotation of the bright spot, placed in the contact point of the infalling matter and the outer disc edge. We estimated some of the parameters of the binary system, on the base of the observational data.

scholarly journals Complex Period Variations of the Neglected W UMa-type Binary System NY Lyrae

2009 ◽  
Vol 26 (1) ◽  
pp. 7-10 ◽  
Author(s):  
S.-B. Qian ◽  
L. Liu ◽  
L.-Y. Zhu
Keyword(s):  
Binary System ◽  
Orbital Period ◽  
Binary Star ◽  
Period Increase ◽  
Photometric And Spectroscopic Observations ◽  
Period Variations ◽  
Cyclic Oscillation ◽  
Careful Investigation ◽  
Interesting System

AbstractOrbital-period variations of the neglected W UMa-type binary star, NY Lyr, were analyzed based on two newly determined eclipse times together with the others compiled from the literature. A cyclic oscillation with a period of 82.1 yr and an amplitude of 0.0247 d was discovered to be superimposed on a continuous period increase (dP/dt = +1.33 × 10−7 d yr−1). After the long-term period increase and the large-amplitude cyclic oscillation were removed from the O–C diagram, the residuals suggest that there is another small-amplitude period oscillation (A4 = 0.0053 d, P4 = 19.4 years) in the orbital period changes. As in the cases of AH Cnc and AD Cnc, both the continuous period increase and the two cyclic period oscillations make NY Lyr an interesting system to study in the future. In order to understand the evolutionary state of the binary system, new photometric and spectroscopic observations and a careful investigation on those data are needed.

Optical spectroscopic monitoring of the Herbig Be binary star HD 200775: New maximum of activity and refinement of the orbital period

2015 ◽  
Vol 70 (3) ◽  
pp. 299-309 ◽  
Author(s):  
A. P. Bisyarina ◽  
A. M. Sobolev ◽  
S. Yu. Gorda ◽  
S. Yu. Parfenov
Keyword(s):  
Orbital Period ◽  
Binary Star ◽  
Spectroscopic Monitoring

scholarly journals Neutron star masses

2012 ◽  
Vol 8 (S291) ◽  
pp. 146-146
Author(s):  
David Nice
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Observational Data ◽  
Mass Distribution ◽  
Binary Star ◽  
Star Mass ◽  
Star Evolution ◽  
Neutron Star Mass ◽  
Present Understanding

AbstractNeutron star masses can be inferred from observations of binary pulsar systems, particularly by the measurement of relativistic phenomena within these orbits. The observed distribution of masses can be used to infer or constrain the equation of state for nuclear matter and to study astrophysical processes such as supernovae and binary star evolution. In this talk, I will review our present understanding of the neutron star mass distribution with an emphasis on the observational data.

Orbital Period of a Binary System in the Field-Boost Approach.

2004 ◽  
Vol 17 (4) ◽  
pp. 435-441
Author(s):  
J. Lucinda ◽  
D. W. Foryta ◽  
M. G. Rodbard
Keyword(s):  
Binary System ◽  
Orbital Period

scholarly journals Fluorescence and Chromospheric Activity of V471 Tau

2002 ◽  
Vol 187 ◽  
pp. 167-172
Author(s):  
T.R. Vaccaro ◽  
R.E. Wilson
Keyword(s):  
Light Curve ◽  
Radial Velocity ◽  
Orbital Period ◽  
White Dwarf ◽  
Binary Star ◽  
Star Model ◽  
Orbital Inclination ◽  
Orbital Parameters ◽  
Maximum Emission ◽  
Chromospheric Activity

AbstractThe red dwarf + white dwarf eclipsing binary V471 Tau shows a variable Hα feature that varies from absorption during eclipse to maximum emission during white dwarf transit. In 1998 we obtained simultaneous BVRI photometry and Hα spectroscopy, with thorough phase coverage of the 12.5 hour orbital period. A binary star model was used with our light curve, radial velocity, and Hα data to refine stellar and orbital parameters. Combined absorption-emission profiles were generated by the model and fit to the observations, yielding a red star radius of 0.94R⊙. Orbital inclination 78° is required with this size and other known parameters. The model includes three spots 1,000 K cooler than the surrounding photosphere. The variable Hα profile was modeled as a chromospheric fluorescing region (essentially on the surface of the red star) centered at the substellar point. Additional emission seen outside our modeled profiles may be large co-rotating prominences that complicate the picture.

scholarly journals IR Geminorum: Complex Disk Behavior During Quiescence

2004 ◽  
Vol 191 ◽  
pp. 259-262
Author(s):  
Zongyun Li ◽  
Kam-Ching Leung ◽  
C. Martin Gaskell
Keyword(s):  
Orbital Period ◽  
V Band ◽  
Eccentric Disk ◽  
Nearly Continuous ◽  
Periodic Cycles

AbstractWe have carried out nearly continuous V-band photometry from Yunnan Observatory (China) and Behlen Observatory (Nebraska, USA) of IR Gem for over six days starting three days after a normal outburst in January 2002. Our observations show that the behavior of this SU UMa star is unexpectedly complicated, and that for IR Gem, quiescence is potentially more interesting than outbursts. We find a photometric modulation with a period of 98.5 min, exactly equal to the spectroscopically determined orbital period. We tentatively attribute this to heating of the secondary. During the first three days a modulation appeared with a period 5% longer than the orbital period. We suggest that this might be a signature of apsidal precession of an eccentric disk. During the middle of our period of observations a modulation with a period 3% shorter than the orbital period appeared. We invoke nodal precession to explain this. A slower modulation we found with a period of about 1.7 d is roughly consistent with the expected period of nodal precession. There is a puzzling 4.3 d period modulation that we suspect may be the result of beating between apsidal and nodal precession frequencies. We also find inexplicable quasi-periodic cycles on timescales drifting from ~ 0.2 to ~ 0.4 days.

scholarly journals Onthe changes in the physical properties of the ionized region around the Weigelt structures in η Carinae over the 5.54-yr spectroscopic cycle

2020 ◽  
Vol 495 (3) ◽  
pp. 2754-2770 ◽  
Author(s):  
M Teodoro ◽  
T R Gull ◽  
M A Bautista ◽  
D J Hillier ◽  
G Weigelt ◽  
...  
Keyword(s):  
Binary System ◽  
Electron Temperature ◽  
Ionization Potential ◽  
Orbital Period ◽  
Equatorial Plane ◽  
Proper Motion ◽  
Emission Lines ◽  
Central Source ◽  
High Ionization ◽  
Orbital Cycle

ABSTRACT We present HST/STIS observations and analysis of two prominent nebular structures around the central source of η Carinae, the knots C and D. The former is brighter than the latter for emission lines from intermediate- or high-ionization potential ions. The brightness of lines from intermediate- and high-ionization potential ions significantly decreases at phases around periastron. We do not see conspicuous changes in the brightness of lines from low-ionization potential (<13.6 eV) ions over the orbital period. Line ratios suggest that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of 106.9 cm−3 that does not significantly change throughout the orbital cycle. The electron temperature varies from 5500 (around periastron) to 7200 K (around apastron). The relative changes in the brightness of the He i lines are well reproduced by the variations in the electron temperature alone. We found that, at phases around periastron, the electron temperature seems to be higher for Weigelt C than that of D. The Weigelt structures are located close to the Homunculus equatorial plane, at a distance of about 1240 au from the central source. From the analysis of proper motion and age, the Weigelt complex can be associated with the equatorial structure called ‘Butterfly Nebula’ surrounding the central binary system.

scholarly journals The multiple system Sk-67°18 in the LMC

1995 ◽  
Vol 163 ◽  
pp. 251-253 ◽  
Author(s):  
V. S. Niemela ◽  
W. Seggewiss ◽  
A. F. J. Moffat
Keyword(s):  
Binary System ◽  
Radial Velocity ◽  
Spectral Type ◽  
Orbital Period ◽  
Large Magellanic Cloud ◽  
Primary Component ◽  
Magellanic Cloud ◽  
Bright Star ◽  
High Mass ◽  
Eclipsing Binary

The bright star Sk—67°18 (Brey 5) in the Large Magellanic Cloud (LMC) contains an eclipsing binary system. Our radial velocity study reveals that the orbital period is almost exactly two days. The spectra also show that the star's primary component is not of spectral type WN, but that the star is rather an Of+O type binary where the primary is probably of type O3f*. Furthermore, Sk—67°18 appears to be a high-mass multiple system.

scholarly journals Multiwavelength Variability in the Symbiotic Nova V1016 CYG

2004 ◽  
Vol 194 ◽  
pp. 224-224
Author(s):  
Š. Parimucha ◽  
M. Vańko
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Orbital Period ◽  
Uv Spectroscopy ◽  
Infrared Photometry ◽  
Symbiotic System ◽  
Photoelectric Photometry ◽  
Mira Variable ◽  
Multiwavelength Variability

Analysis of the optical and infrared photometry together with UV spectroscopy led to discovery of the 15-years periodicity in the symbiotic system V1016 Cyg. This period could be interpreted as a orbital period in the binary system consisting of the Mira variable and the hot white dwarf.We have analyzed long-term optical photographic and UBV photoelectric photometry of V1016 Cyg. Collected observations cover pre- and post-outburst stages of the system. The light, curve suggests four stages of activity: the pre-out burst flare in 1949, the main nova-like outburst in 1904, and two post-outbursts, decreasing-amplitude flares in 1980 and 1994, respectively. Activity episodes affecting the system repeat with an interval of ~ 15 years. The ephemeris for the activity maxima is (see Parimucha et al., 2000).

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