Starspots and photometric noise on observed minus calculated (O–C) diagrams

Kalimeris, A.; Rovithis‐Livaniou, H.; Rovithis, P.

doi:10.1051/0004-6361:20020456

Cited by 94 publications

(100 citation statements)

References 14 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The final column includes the code ECC to identify those systems with a non-zero eccentricity as indicated by significantly differing epochs of eclipse, The variations due to starspots are often found only in the timings for the eclipse of the cooler secondary component (for example, KIC 10581918 = WX Dra, an Algol-type binary; Figure 1.35). These variations are caused by the change in the surface intensity and center of light over the visible hemisphere (Kalimeris et al 2002;Tran et al 2013). For example, suppose a dark spot group rotates into view on the approaching portion of the eclipsed star.…”

Section: Eclipse Timing Measurementsmentioning

confidence: 99%

KEPLERECLIPSING BINARIES WITH STELLAR COMPANIONS

Gies

Matson

Guo

et al. 2015

View full text Add to dashboard Cite

Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses of both stellar components. We present preliminary orbital elements for seven probable triple stars among this sample, and we discuss apparent period changes in seven additional eclipsing binaries that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these binaries for further evidence of the presence of third stars.

show abstract

Section: Eclipse Timing Measurementsmentioning

confidence: 99%

KEPLERECLIPSING BINARIES WITH STELLAR COMPANIONS

Gies

Matson

Guo

et al. 2015

View full text Add to dashboard Cite

show abstract

“…In the last decade other mathematical methods have been developed for the analysis of O−C curves as well (see e.g. Kalimeris et al 1994a;Jetsu et al 1997). The main reason why we did not apply any of these methods is that we used "a priori" knowledge on the trace of the LITE on the O−C diagram.…”

Section: Period Variationsmentioning

confidence: 99%

“…by the radial velocity of the mass centre of the system (see Kopal 1959), the apsidal motion (see Claret 1997 for a review), the light-time effect (see e.g. Frieboes-Conde & Herczeg 1973;Borkovits & Hegedüs 1996), mass transfer, and magnetic activity (see Applegate 1992;Kalimeris et al 1994b;Kaszás et al 1998, or more recently Zavala et al 2002, and the criticism of the magnetic activity-period variations connections in van't Veer 1991). In the present paper we shall investigate the properties of the light-time effect (LITE) in the case of IM Aurigae and it will also be shown how the third light affects the light-curve solution in this particular example.…”

Section: Introductionmentioning

confidence: 99%

Complex Period Variations in the Binary System IM Aurigae

Borkovits

Csizmadia

Hegedüs³

et al. 2002

A&A

View full text Add to dashboard Cite

Abstract.Results of a new light-curve analysis and period variation study of the eclipsing binary IM Aur are presented. Four solutions are given according to the different spectral types of the primary, available in the literature. Multicolour photometry and the period analysis both indicate a close (≈0. 1) third physical member. If it is considered as a main-sequence star, then its spectral type is A2V-A8V, with a mass of m 3 ≈ 1.7−2.5 M . The light-time effect is modelled by the authors' simultaneous secular and periodic terms fitting code. Clear evidence of a secular period change is also revealed. The detailed effects of the perturbations by a third member of a close binary system are extensively studied, using one of the authors' latest numerical integrator code. Although the amplitudes of the expected O−C changes are too small and also the data set is far undersampled for clear confirmation of the theoretical expectation of the third body-perturbed eclipsing binary O−C curve, some typical patterns are shown for their possible identification amongst the O−C curves of other closer systems (like Algol, λ Tau) in the near future.

show abstract

“…Apart from these errors, whose nature is purely statistical, the photometric noise caused by the heterogeneous surface of the stellar components, characterizing mainly late-type stars, is able to misguide any inference from O-C diagrams analysis. It is expected that photometric noise does not exceed 0.01 d when migrating spots drift on the surface of a binary component (Ogloza 1997;Kalimeris et al 2002).…”

Section: Mathematical Proceduresmentioning

confidence: 99%

Efficiency of O–C diagrams as diagnostic tools for long-term period variations

Nanouris

Kalimeris

Antonopoulou

et al. 2011

A&A

Self Cite

View full text Add to dashboard Cite

Context. The credibility of an O-C diagram analysis is investigated when long-term processes are examined in binary systems. The morphology of period and O-C diagrams is thoroughly explored when mass loss and magnetic braking, induced by stellar winds, drive the orbital evolution of late-type detached binaries. Conditions are specified that determine which process dominates. Aims. Our objective is to determine the minimum time intervals that observations are expected to span for a physical mechanism to be detectable by means of an O-C diagram analysis. Computations for various values that account for the noise level and the orbital period are performed to find out to which degree these affect the inferred intervals. Methods. GeneralizedJ −Ṗ relations that govern the orbital evolution of a binary system are set and solved analytically to determine in a closed form the period and the function expected to represent the respective O-C variations. Semi-empirical relations adapting mass loss and magnetic braking processes for single cool stars are adopted and properly modified to be consistent with the latest observational constraints. A standard Newton-Raphson numerical procedure is then employed to estimate the minimum temporal range over which a specific mechanism is rendered measurable. Results. Mass loss rates comparable to or greater than −10 −9 M yr −1 are measurable for typical noise levels of the O-C diagrams when the data span more than a century. Magnetic braking was proved to be very sensitive on the orbital period and on the braking law adopted for inference. It is expected to be detectable in current O-C diagrams of very short-period binaries only, for others it needs at least two centuries of observations to confirm its effects safely. Conclusions. Both wind driven mass loss and magnetic braking processes are able to drive the orbital evolution of short-period detached binaries (P orb 1 d) in amounts traced on human timescales. There are also special conditions under which their strength is equalized, locking the orbital period invariable in time. Several short-period RS CVn-type binaries are fine candidates where this regime is expected to prevail.

show abstract

Starspots and photometric noise on observed minus calculated (O–C) diagrams

Cited by 94 publications

References 14 publications

KEPLERECLIPSING BINARIES WITH STELLAR COMPANIONS

KEPLERECLIPSING BINARIES WITH STELLAR COMPANIONS

Complex Period Variations in the Binary System IM Aurigae

Efficiency of O–C diagrams as diagnostic tools for long-term period variations

Contact Info

Product

Resources

About