The orbital period changes of UX Ursae Majoris

Rubenstein, Eric; Patterson, Joseph; Africano, J. L.

doi:10.1086/132945

Cited by 19 publications

(9 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cyclical orbital period changes are seen in many eclipsing CVs (Warner 1995, and references therein). The cycle periods range from 4 yr in EX Dra (Baptista et al 2000) to about 30 yr in UX UMa (Rubenstein, Patterson & Africano 1991), whereas the amplitudes are in the range 10 1 –10 2 s. Therefore, V2051 Oph and V4140 Sgr fit nicely in the overall picture drawn from the observations of orbital period changes in CVs.…”

Section: Discussionmentioning

confidence: 56%

Cyclical period changes in the dwarf novae V2051 Oph and V4140 Sgr

Baptista¹,

Bond²,

Jablonski³

et al. 2003

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We report the identification of cyclical changes in the orbital period of the eclipsing dwarf novae V2051 Ophiuchi and V4140 Sagitarii. We used sets of white dwarf mid-eclipse timings to construct observed-minus-calculated diagrams covering, respectively, 25 and 16 years of observations. The V2051 Oph data present cyclical variations that can be fitted by a linear plus sinusoidal function with period 22 +/- 2 yr and amplitude 17 +/- 3 s. The statistical significance of this period by an F-test is larger than 99.9 per cent. The V4140 Sgr data present cyclical variations of similar amplitude and period 6.9 +/- 0.3 yr which are statistically significant at the 99.7 per cent level. We derive upper limits for secular period changes of |dP/dt| < 3x10^{-12} and |dP/dt| < 1.8x10^{-11}, respectively for V2051 Oph and V4140 Sgr. We combined our results with those in the literature to construct a diagram of the amplitude versus period of the modulation for a sample of 11 eclipsing cataclysmic variables (CVs). If the cyclical period changes are the consequence of a solar-type magnetic activity cycle in the secondary star, then magnetic activity is a widespread phenomenon in CVs, being equally common among long- and short-period systems. This gives independent evidence that the magnetic field (and activity) of the secondary stars of CVs do not disappear when they become fully convective. We also find that the fractional cycle period changes of the short-period CVs are systematically smaller than those of the long-period CVs.Comment: 9 pages, 4 postscript figures, coded with MNRAS latex style file. To appear in Monthly Notices of the Royal Astronomical Societ

show abstract

Section: Discussionmentioning

confidence: 56%

Cyclical period changes in the dwarf novae V2051 Oph and V4140 Sgr

Baptista¹,

Bond²,

Jablonski³

et al. 2003

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Cyclical orbital period changes are seen in many eclipsing CVs (Warner 1995 and references therein). The cycle periods range from 4 yr in EX Dra (Baptista et al 2000) to about 30 yr in UX UMa (Rubenstein, Patterson & Africano 1991), whereas the amplitudes are in the range 0.1–2.5 min. Therefore, Z Cha fits nicely in the overall picture drawn from the observations of orbital period changes in CVs.…”

Section: Discussionmentioning

confidence: 99%

Cyclical period changes in Z Chamaeleontis

Baptista

Jablonski

Oliveira

et al. 2002

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We report the identification of cyclical changes in the orbital period of the eclipsing dwarf nova Z Cha. We used times of mid-eclipse collected from the literature and our new eclipse timings to construct an observed-minus-calculated diagram covering 30 years of observations (1972-2002). The data present cyclical variations that can be fitted by a linear plus sinusoidal function with period 28+/-2 yr and amplitude 1.0+/-0.2 minute. The statistical significance of this period by an F-test is larger than 99.9%. The derived fractional period change, Delta P/P= 4.4 x 10^{-7}, is comparable to that of other short-period cataclysmic variables (CVs), but is one order of magnitude smaller than those of the long-period CVs. Separate fits to the first and second half of the data lead to ephemerides with quite different cycle periods and amplitudes, indicating that the variation is not sinusoidal or, most probably, is not strictly periodic. The observed cyclical period change is possibly caused by a solar-type magnetic activity cycle in the secondary star. An incremental variation in the Roche lobe of the secondary star of Delta R_{L2}/R_{L2} = 1.7 x 10^{-4} is required in order to explain both the observed period change and the modulation of the quiescent brightness previously reported by Ak, Ozkan & Mattei.Comment: 5 pages, 1 postscript figure, coded with MNRAS latex style file. To appear in Monthly Notices of the Royal Astronomical Societ

show abstract

“…For example, RW Tri was observed by Honeycutt et al (1994b) to show sinusoidal-like brightness variations of 0.5 magnitude with a period of 25 days. RW Tri and UX UMa also show aperiodic variations in their orbital period (Still et al 1995a;Rubenstein et al 1991). There have been suggestions that these phenomena might be the result of magnetic cycles within the secondary star -see Applegate (1992) and references therein.…”

Section: Observed Propertiesmentioning

confidence: 98%

The Nova-Like Variables

Dhillon

1996

Cataclysmic Variables and Related Objects

View full text Add to dashboard Cite

Abstract. We review optical observations and theoretical models of the non-magnetic nova-like variables (UX UMa, VY Scl and SW Sex stars). A brief discussion of the classification scheme is followed by a statistical overview of the observed properties. The most important features of each of the sub-classes are then reviewed, concluding with a summary of the theoretical models invoked to understand these systems. ClassificationNova-like variables are defined as cataclysmic variable stars (CVs) which have never been observed to undergo nova or dwarf nova-type outbursts. Such a crude definition encompasses a wide variety of objects which can be divided into two distinct groups; those which are believed to accrete via magnetic field lines -AM Her stars (or polars), DQ Her stars and intermediate polars -and those which are believed to accrete via an accretion disc -UX UMa stars, VY Scl stars (or anti-dwarf novae), SW Sex stars and AM CVn stars (or double-degenerates). The magnetic nova-likes have been reviewed elsewhere in this volume. The subject of this review will be the optical characteristics of non-magnetic nova-likes (NMNLs), with the exception of the AM CVn stars which are outside the scope of this paper.There is little agreement on the classification scheme for NMNLs in the literature. Perhaps the most generally accepted scheme adheres to the following rules: if a nova-like shows no evidence for magnetic accretion and is not recognized to be a double-degenerate, it is classed as a UX UMa star. A UX UMa star which is observed to show states of low brightness becomes a VY Scl star. A number of UX UMa and VY Scl stars with high inclinations and periods of 3-4 hr, show single-peaked emission lines which remain (largely) unobscured during primary eclipse and which exhibit transient absorption features and distorted radial velocity curves. These systems were

show abstract

The orbital period changes of UX Ursae Majoris

Cited by 19 publications

References 15 publications

Cyclical period changes in the dwarf novae V2051 Oph and V4140 Sgr

Cyclical period changes in the dwarf novae V2051 Oph and V4140 Sgr

Cyclical period changes in Z Chamaeleontis

The Nova-Like Variables

Contact Info

Product

Resources

About