scholarly journals The Lower Main Sequence and the Orbital Period Distribution of Cataclysmic Variable Stars

1998 ◽  
Vol 496 (1) ◽  
pp. 352-363 ◽  
Author(s):  
J. Christopher Clemens ◽  
I. Neill Reid ◽  
John E. Gizis ◽  
M. Sean O'Brien
Keyword(s):  
Orbital Period ◽  
Main Sequence ◽  
Variable Stars ◽  
Cataclysmic Variable ◽  
Period Distribution

scholarly journals The Orbital Period Distribution of Cataclysmic Variables Found by the SDSS

2011 ◽  
Vol 7 (S282) ◽  
pp. 123-124 ◽  
Author(s):  
John Southworth ◽  
Boris T. Gänsicke ◽  
Elmé Breedt
Keyword(s):  
Angular Momentum ◽  
Orbital Period ◽  
Cataclysmic Variables ◽  
Sloan Digital Sky Survey ◽  
Cataclysmic Variable ◽  
Minimum Period ◽  
Period Distribution ◽  
Sky Survey ◽  
Short Period ◽  
Angular Momentum Loss

AbstractThe orbital period is one of the most accessible observables of a cataclysmic variable. It has been a concern for many years that the orbital period distribution of the known systems does not match that predicted by evolutionary theory. The sample of objects discovered by the Sloan Digital Sky Survey has changed this: it shows the long-expected predominance of short-period objects termed the ‘period spike’. The minimum period remains in conflict with theory, suggesting that the angular momentum loss mechanisms are stronger than predicted.

scholarly journals Cataclysmic Variable Stars

1998 ◽  
Vol 11 (1) ◽  
pp. 16-27
Author(s):  
Brian Warner
Keyword(s):  
White Dwarf ◽  
Binary Systems ◽  
Main Sequence ◽  
Variable Stars ◽  
Cataclysmic Variable ◽  
Common Envelope ◽  
Short Period ◽  
Orbital Periods ◽  
Probable Origin ◽  
Binary Orbit

The evolution of single stars on and away from the main sequence is well understood. A degenerate core is formed in a star as the star leaves the main sequence and expands to a giant with a radius typically 50 - 500 Ro . Observationally it is known that most stars are members of binary systems, and among these many have orbital periods less than 100 y. It can happen, therefore, that the expanding envelope of the primary of a binary system can reach to the secondary. As this happens, the primary fills its Roche tidal lobe and transfers matter to the secondary; if the primary has a radiative envelope the rate at which this occurs exceeds the Eddington limit of the secondary, which therefore repels the incoming gas, forming a common envelope around the two stars. Friction within the envelope causes the stars to spiral towards each other until the energy and angular momentum extracted from the binary orbit and transferred to the envelope are sufficient to eject the common envelope as a planetary nebula, leaving a short period binary comprising a white dwarf and a main sequence star. This mechanism of producing short period binaries containing white dwarfs, proposed by Ostriker and by Paczynski (1976), is the probable origin of the class of objects known as Cataclysmic Variable Stars (CVs), which encompass the classical novae, dwarf novae, novalike variables and a variety of related objects. Evidence has been accumulating for forty years (Crawford & Kraft 1956, Warner 1995a) that every CV consists of a secondary star (usually a dwarf, but a few systems contain giants) filling its Roche lobe and transferring mass to a white dwarf primary. In systems of normal chemical composition the orbital periods lie between 75 mins and ~250 d, with the majority having . A few hydrogen-free systems are known for which 17 mins < Porb < 50 mins. It should be noted that CVs are very compact binary systems: for h such a binary would fit inside the Sun.

The study of short orbital period of delta scuti pulsating variable stars

2019 ◽  
Vol 15 (S356) ◽  
pp. 407-407
Author(s):  
Abduselam Mohammed
Keyword(s):  
Time Delay ◽  
Orbital Period ◽  
Binary Stars ◽  
Arrival Time ◽  
Periodic Variation ◽  
Variable Stars ◽  
Orbital Elements ◽  
Pulsating Stars ◽  
Delta Scuti ◽  
Arrival Time Delay

AbstractAs a pulsating star moves in its binary orbit, the path length of the light between us and the star varies, leading to the periodic variation in the arrival time of the signal from the star to us (earth). With the consideration of pulsators light arrival time delay effects several new methods which allows using Kepler photometric data (light curves) alone to find binary stars have been recently developed. Among these modern techniques we used binarogram method and we identified that several δSct pulsating stars have companions. The application of these method on detecting long periods(i.e. longer than about 50 d) δSct pulsating stars is not new, but the uniqueness of this study is we verified that it is also applicable to detect and determine the orbital elements of short periods (i.e short orbital period) δSct pulsating stars. With this investigation, we identified the possible way to overcome effects of fictious peaks, even, on the maximum peaks helpful to verify weather the star has companion or not depend up on the existence of the time-delay. Then, we applied the technique on known binary stars and their orbital elements are previously published. Finally, we identified some new short orbital period δSct pulsating stars and obtained their orbital frequency and period with the same procedures. Because of with our attempts we succeeded and verified the applicability of the method (the Binarogram method) on these stars (i.e short orbital period) for the first time, we expect that our present study will play a great role for similar study and to improve our binary statistics.

scholarly journals RAPID DECREASING IN THE ORBITAL PERIOD OF THE DETACHED WHITE DWARF–MAIN SEQUENCE BINARY SDSS J143547.87+373338.5

2016 ◽  
Vol 817 (2) ◽  
pp. 151 ◽  
Author(s):  
S.-B. Qian ◽  
Z.-T. Han ◽  
B. Soonthornthum ◽  
L.-Y. Zhu ◽  
J.-J. He ◽  
...  
Keyword(s):  
Orbital Period ◽  
White Dwarf ◽  
Main Sequence

Angular Momentum Losses and the Orbital Period Distribution of Cataclysmic Variables below the Period Gap: Effects of Circumbinary Disks

2005 ◽  
Vol 635 (2) ◽  
pp. 1263-1280 ◽  
Author(s):  
Bart Willems ◽  
Ulrich Kolb ◽  
Eric L. Sandquist ◽  
Ronald E. Taam ◽  
Guillaume Dubus
Keyword(s):  
Angular Momentum ◽  
Orbital Period ◽  
Cataclysmic Variables ◽  
Period Distribution ◽  
Gap Effects

scholarly journals V479 And: CV, LMXB, or Symbiotic?

2011 ◽  
Vol 7 (S281) ◽  
pp. 113-116
Author(s):  
Diego González Buitrago ◽  
Gagik Tovmassian ◽  
Juan Echevarría ◽  
Sergey Zharikov ◽  
Takamitsu Miyaji ◽  
...  
Keyword(s):  
Orbital Period ◽  
Main Sequence ◽  
Compact Object ◽  
Close Binary System ◽  
Close Binary ◽  
Stellar Winds ◽  
Primary Star ◽  
Giant Star ◽  
X Ray ◽  
Low Mass

AbstractV479 And is a 14.26 hour, close binary system, comprised of a G8-K0 star departing from the main sequence and a compact primary star accreting matter from the donor. The object is an X-ray source, modulated with the orbital period. This, and the presence of an intense He II line, leads us to speculate that the compact object is a magnetic white dwarf. However, we do not find strong constraints on the upper mass limit of the compact object, and we may have a neutron star in a low mass X-ray binary instead of a cataclysmic variable. The orbital period is certainly too short for the donor star to be an evolved giant star, so classifying this object as a symbiotic binary may be a big stretch; however there is an evidence that the mass transfer occurs via stellar winds, rather than through the L1 point of Roche filling secondary, a phenomenon more common for symbiotic stars.

On the Properties of Galactic Novae and Their Orbital Period Distribution

2004 ◽  
Vol 602 (2) ◽  
pp. 938-947 ◽  
Author(s):  
Lorne A. Nelson ◽  
Keith A. MacCannell ◽  
Ernest Dubeau
Keyword(s):  
Orbital Period ◽  
Period Distribution
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