New or Improved Orbital Periods of Cataclysmic Binaries

A zero-age cataclysmic binary (ZACB) we define as a binary system at the onset of interaction as a cataclysmic variable. We present here the results of calculations of the distributions of white dwarf masses and of orbital periods in ZACBs, due to binaries present in a stellar population which has undergone continuous, constant star formation for 1010 years.Distributions of ZACBs were calculated for binaries formed t years ago, for log t = 7.4 (the youngest age at which viable ZACBs can form) to log t = 10.0 (the assumed age of the Galactic disk), in intervals of log t = 0.1. These distributions were then integrated over time to obtain the ZACB distribution for a constant rate of star formation. To compute the individual distributions for a given t, we require the density of systems forming (number of pre-cataclysmics forming per unit volume of orbital parameter space), n£(t), and the rates at which the radii of the secondary and of its Roche lobe are changing in time, s (t) and L, s (t), respectively. In calculating nf(t), we assume that the distribution of the orbital parameters in primordial (ZAMS) binaries may be written as the product of the distribution of masses of ZAMS stars (Miller and Scalo 1979), the distribution of mass ratios in ZAMS binaries (cf. Popova, et al., 1982), and the distribution of orbital periods in ZAMS binaries (Abt 1983). In transforming the the orbital parameters from progenitor (ZAMS) to offspring (ZACB) binaries, we assume that all of the orbital energy deposited into the envelope during the common envelope phase leading to ZACB formation goes into unbinding that envelope. R.L, s (t) is determined from orbital angular momentum loss rates due to gravitational radiation (Landau and Lifshitz 1951) and magnetic braking (γ = 2 in Rappaport, Verbunt, and Joss 1983). We turn off magnetic braking if the secondary is completely convective.

Download Full-text

Close-In Substellar Companions and the Formation of sdB-Type Close Binary Stars

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2015.02.0183 ◽

2015 ◽

Vol 2 (1) ◽

pp. 183-187 ◽

Cited By ~ 1

Author(s):

L. Y. Zhu ◽

S. B. Qian ◽

E.-G. Zhao ◽

E. Fernández Lajús ◽

Z.-T. Han

Keyword(s):

Binary Stars ◽

Eclipsing Binaries ◽

Close Binary ◽

Close Binaries ◽

Close Binary Stars ◽

Cataclysmic Binaries ◽

Low Mass ◽

Substellar Companions ◽

Orbital Periods

The sdB-type close binaries are believed to have experienced a common-envelope phase and may evolve into cataclysmic binaries (CVs). About 10% of all known sdB binaries are eclipsing binaries consisting of very hot subdwarf primaries and low-mass companions with short orbital periods. The eclipse profiles of these systems are very narrow and deep, which benefits the determination of high precise eclipsing times and makes the detection of small and close-in tertiary bodies possible. Since 2006 we have monitored some sdB-type eclipsing binaries to search for the close-in substellar companions by analyzing the light travel time effect. Here some progresses of the program are reviewed and the formation of sdB-type binary is discussed.

Download Full-text

The Evolutionary Status of the Secondaries of Cataclysmic Binaries

International Astronomical Union Colloquium ◽

10.1017/s0252921100090394 ◽

1983 ◽

Vol 72 ◽

pp. 257-262

Author(s):

H. Ritter

Keyword(s):

Probability Distribution ◽

Main Sequence ◽

The Other ◽

Initial Mass ◽

Evolutionary Status ◽

Mass Ratio ◽

Main Sequence Stars ◽

Cataclysmic Binaries ◽

Low Mass ◽

Orbital Periods

ABSTRACTIt is shown that the secondary components of cataclysmic binaries with orbital periods of less than ~10 hours are indistinguishable from ordinary low-mass main-sequence stars and that, therefore, they are essentially unevolved. On the other hand, it is shown that, depending on the mass ratio of the progenitor system, the secondary of a cataclysmic binary could be significantly evolved. The fact that nevertheless most of the observed secondaries are essentially unevolved can be accounted for by assuming that the probability distribution for the initial mass ratio is not strongly peaked towards unity mass ratio.

Download Full-text

Optical Studies of 10 Hard X-Ray-selected Cataclysmic Binaries

The Astrophysical Journal ◽

10.3847/1538-4357/ac2f9f ◽

2022 ◽

Vol 924 (2) ◽

pp. 67

Author(s):

Jules P. Halpern ◽

John R. Thorstensen

Keyword(s):

Cataclysmic Variables ◽

Velocity Variation ◽

Time Resolved ◽

X Ray ◽

Spin Period ◽

Radial Velocity Variation ◽

Cataclysmic Binaries ◽

Orbital Periods ◽

Magnetic Cataclysmic Variables ◽

Optical Identifications

Abstract We conducted time-resolved optical spectroscopy and/or photometry of 10 cataclysmic binaries that were discovered in hard X-ray surveys, with the goal of measuring their orbital periods and searching for evidence that they are magnetic. Four of the objects in this study are new optical identifications: IGR J18017−3542, PBC J1841.1+0138, IGR J18434−0508, and Swift J1909.3+0124. A 311.8 s, coherent optical pulsation is detected from PBC J1841.1+0138, as well as eclipses with a period of 0.221909 days. A 152.49 s coherent period is detected from IGR J18434−0508. A probable period of 389 s is seen in IGR J18151−1052, in agreement with a known X-ray spin period. We also detect a period of 803.5 s in an archival X-ray observation of Swift J0717.8−2156. The last four objects are thus confirmed magnetic cataclysmic variables of the intermediate polar class. An optical period of 1554 s in AX J1832.3−0840 also confirms the known X-ray spin period, but a stronger signal at 2303 s is present whose interpretation is not obvious. We also studied the candidate intermediate polar Swift J0820.6−2805, which has low and high states differing by ≈4 mag and optical periods or quasi-periodic oscillations not in agreement with proposed X-ray periods. Of note is an unusually long 2.06-day orbital period for Swift J1909.3+0124, manifest in the radial velocity variation of photospheric absorption lines of an early K-type companion star. The star must be somewhat evolved if it is to fill its Roche lobe.

Download Full-text

Orbital Periods for the Cataclysmic Binaries VZ Pyxidis, CC Cancri, and AH Eridani

Publications of the Astronomical Society of the Pacific ◽

10.1086/134002 ◽

1997 ◽

Vol 109 ◽

pp. 1241 ◽

Cited By ~ 9

Author(s):

J. R. Thorstensen

Keyword(s):

Cataclysmic Binaries ◽

Orbital Periods

Download Full-text

From the Oort cloud to Halley-type comets

International Astronomical Union Colloquium ◽

10.1017/s0252921100031638 ◽

1999 ◽

Vol 173 ◽

pp. 327-338 ◽

Cited By ~ 5

Author(s):

J.A. Fernández ◽

T. Gallardo

Keyword(s):

Total Population ◽

Complex Function ◽

Dynamical Evolution ◽

Oort Cloud ◽

Capture Process ◽

Influx Rate ◽

Short Period ◽

Dynamical Properties ◽

Orbital Periods ◽

Probability Of Capture

AbstractThe Oort cloud probably is the source of Halley-type (HT) comets and perhaps of some Jupiter-family (JF) comets. The process of capture of Oort cloud comets into HT comets by planetary perturbations and its efficiency are very important problems in comet ary dynamics. A small fraction of comets coming from the Oort cloud − of about 10−2− are found to become HT comets (orbital periods < 200 yr). The steady-state population of HT comets is a complex function of the influx rate of new comets, the probability of capture and their physical lifetimes. From the discovery rate of active HT comets, their total population can be estimated to be of a few hundreds for perihelion distancesq <2 AU. Randomly-oriented LP comets captured into short-period orbits (orbital periods < 20 yr) show dynamical properties that do not match the observed properties of JF comets, in particular the distribution of their orbital inclinations, so Oort cloud comets can be ruled out as a suitable source for most JF comets. The scope of this presentation is to review the capture process of new comets into HT and short-period orbits, including the possibility that some of them may become sungrazers during their dynamical evolution.

Download Full-text

The Role of Saturn's Oblateness in the Mimas-Tethys Resonance

Symposium - International Astronomical Union ◽

10.1017/s0074180900070406 ◽

1974 ◽

Vol 62 ◽

pp. 71-76

Author(s):

R. Greenberg

Keyword(s):

Saturn’S Satellites ◽

Orbital Periods

Saturn's satellites Mimas and Tethys appear to be involved in a unique resonance. All orbit-orbit resonances, by definition, have the satellites' conjunction librating about some specific longitude. Equivalently, their orbital periods, measured relative to that longitude, are commensurable. Most orbit-orbit resonances are of the eccentricity-type; the conjunctions librate about the longitude of an apse of one orbit. The Mimas-Tethys resonance is of the inclination type.

Download Full-text

X-Ray Sources in Close Binary Systems

Highlights of Astronomy ◽

10.1017/s1539299600001842 ◽

1974 ◽

Vol 3 ◽

pp. 89-107

Author(s):

M. J. Rees

Keyword(s):

Binary Systems ◽

Close Binary ◽

Rapid Variability ◽

X Ray ◽

Close Binary Systems ◽

General Order ◽

Typical Distances ◽

Astronomical Research ◽

Orbital Periods ◽

Galactic Sources

The discovery by Giacconi and his colleagues of variable X-ray sources in close binary systems certainly ranks as one of the highlights of astronomical research during the last 3 years. These remarkable objects have already been extensively studied, by optical and radio observations as well as in the X-ray band; and they seem likely to prove as significant and far-reaching in their implications as pulsars.The ‘Third Uhuru Catalogue’ (Giacconi et al., 1973a) contains about 160 sources, of which about 100 lie in our Galaxy. Their distribution over the sky (together with other arguments) suggests that these sources have luminosities of the general order 1036–1038 erg s−1, and that their typical distances are ˜ 10kpc. These galactic sources generally display rapid variability. Little else is known about most of them, but they are probably of the same general class as systems such as Her X1, Cen X3, Cyg X1 and Cyg X3. These sources have been investigated in detail, and in all cases one infers a system where the X-ray source is orbiting around a relatively ordinary star. Six sources have been optically identified, and there are some others whose binary nature is established by the occurrence of an X-ray eclipse. Orbital periods range from 4.8 h (Cyg X3) up to ˜ 10 days.

Download Full-text

Spectroscopy of the Cataclysmic Binaries CY Lyrae, TW Trianguli, and VW Vulpeculae

Publications of the Astronomical Society of the Pacific ◽

10.1086/316282 ◽

1998 ◽

Vol 110 (754) ◽

pp. 1405-1411 ◽

Cited By ~ 20

Author(s):

John R. Thorstensen ◽

Cynthia J. Taylor ◽

Jonathan Kemp

Keyword(s):

Cataclysmic Binaries

Download Full-text

Dynamical evolution of Oort cloud comets to near-Earth space

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307003055 ◽

2006 ◽

Vol 2 (S236) ◽

pp. 43-54 ◽

Cited By ~ 1

Author(s):

Olga A. Mazeeva

Keyword(s):

Dynamical Evolution ◽

Absolute Magnitude ◽

Oort Cloud ◽

Outer Solar System ◽

Earth Space ◽

Near Earth Space ◽

Long Period ◽

Order Of Magnitude ◽

Orbital Periods ◽

Stellar Perturbations

AbstractThe dynamical evolution of 2⋅105 hypothetical Oort cloud comets by the action of planetary, galactic and stellar perturbations during 2⋅109 years is studied numerically. The evolution of comet orbits from the outer (104 AU <a<5⋅104 AU, a is semimajor axes) and the inner Oort cloud (5⋅103 AU <a<104 AU) to near-Earth space is investigated separately. The distribution of the perihelion (q) passage frequency in the planetary region is obtained calculating the numbers of comets in every interval of Δ q per year. The flux of long-period (LP) comets (orbital periods P>200 yr) with perihelion distances q<1.5 AU brighter than visual absolute magnitude H10=7 is ∼ 1.5 comets per year, and ∼18 comets with H10<10.9. The ratio of all LP comets with q<1.5 AU to ‘new’ comets is ∼5. The frequency of passages of LP comets from the inner Oort cloud through region q<1.5 AU is ∼3.5⋅10−13 yr−1, that is roughly one order of magnitude less than frequency of passages of LP comets from the outer cloud (∼5.28⋅10−12 yr−1). We show that the flux of ‘new’ comets with 15<q<31 AU is higher than with q<15 AU, by a factor ∼1.7 for comets from the outer Oort cloud and, by a factor ∼7 for comets from the inner cloud. The perihelia of comets from the outer cloud previously passed through the planetary region are predominated in the Saturn-Uranus region. The majority of inner cloud comets come in the outer solar system (q>15 AU), and a small fraction (∼0.01) of them can reach orbits with q<1.5 AU. The frequency of transfer of comets from the inner cloud (a<104 AU) to the outer Oort cloud (a>104 AU), from where they are injected to the region q<1.5 AU, is ∼6⋅10−14 yr−1.

Download Full-text