Pulsating Stars in Close Binaries. I. Investigations of Eclipse Mapping and Oblique Pulsations

Reed, M. D.; Brondel, B. J.; Kawaler, S. D.

doi:10.1086/491666

Cited by 47 publications

(54 citation statements)

References 33 publications

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“…If some kind of unknown pulsation is assumed, along with binarity, then the modulation could reflect the misalignment between the orbital axis and the pulsational axis, produced by the tidal force of the faint stellar component. In fact, Reed & Brondel (2005) report modulated light curves in these cases, very similar to that shown in Fig. 2.…”

Section: Ogle00445466-7328029 (Smc3-2)supporting

confidence: 77%

Blue and yellow long-period variables in the direction of the Small Magellanic Cloud

Mennickent¹,

Cidale²,

Pietrzyński

et al. 2006

A&A

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Aims. We investigate the nature of a sample of 17 long-term periodic variables in the direction of the Small Magellanic Cloud. Methods. Based on new spectroscopic data, we determined spectral types, radial velocities, absolute magnitudes, and colors for these stars. We present a refined discussion of their OGLE light curves along with an analysis of their 2MASS photometry. Results. Most stars turned out to be B-A giants members of the Small Magellanic Cloud. We find a new interacting eclipsing binary with a period of 184 days and two new early-type ellipsoidal variables. One of our objects is the ROSAT source RX J0058.2-7231. We analyzed 11-years of data for this Be X-ray binary finding that their photometric period varies by ∼4% quasiperiodically, on a time scale of ∼1200 days. We find evidence of multiple photometric periods in 2 Ae-type and 1 late-Be type stars. The case of OGLE00445466-7328029 is especially interesting, as this late-type Be star shows a beating phenomenon primarily caused by two closely-spaced frequencies, 0.

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Section: Ogle00445466-7328029 (Smc3-2)supporting

confidence: 77%

Blue and yellow long-period variables in the direction of the Small Magellanic Cloud

Mennickent¹,

Cidale²,

Pietrzyński

et al. 2006

A&A

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“…The combined presence of pulsations and eclipses, furthermore, offers the possibility of eclipse mapping, as done for example for NY Vir (Reed et al 2005;Reed & Whole Earth Telescope Xcov 21 and 23 Collaborations 2006). Thereby, the eclipses can be used to determine pulsation modes, which are often difficult to uniquely identify.…”

Section: Discussionmentioning

confidence: 99%

An eclipsing post common-envelope system consisting of a pulsating hot subdwarf B star and a brown dwarf companion

Schaffenroth

Barlow

Drechsel

et al. 2015

A&A

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Hot subdwarf B stars (sdBs) are evolved, core helium-burning objects located on the extreme horizontal branch. Their formation history is still puzzling because the sdB progenitors must lose nearly all of their hydrogen envelope during the red-giant phase. About half of the known sdBs are in close binaries with periods from 1.2 h to a few days, which implies that they experienced a common-envelope phase. Eclipsing hot subdwarf binaries (also called HW Virginis systems) are rare but important objects for determining fundamental stellar parameters. Even more significant and uncommon are those binaries containing a pulsating sdB, since the mass can be determined independently by asteroseismology. Here we present a first analysis of the eclipsing hot subdwarf binary V2008-1753. The light curve shows a total eclipse, a prominent reflection effect, and low-amplitude pulsations with periods from 150 to 180 s. An analysis of the light-and radial velocity curves indicates a mass ratio close to q = 0.146, an radial velocity semi-amplitude of K = 54.6 km s −1 , and an inclination of i = 86.8• . Combining these results with our spectroscopic determination of the surface gravity, log g = 5.83, the best-fitting model yields an sdB mass of 0.47 M and a companion mass of 69 M Jup . Because the latter mass is below the hydrogen-burning limit, V2008-1753 represents the first HW Vir system that is known to consist of a pulsating sdB and a brown dwarf companion. Consequently, it holds strong potential for better constraining models of sdB binary evolution and asteroseismology.

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“…Kepler can test this critical model assumption in that with more data and a lower detection threshold, it may be possible to determine if l > 3 are indeed present. As l ≥ 3 have a large degree of geometric cancellation (Charpinet et al 2005; Reed, Brondel & Kawaler 2005), if their amplitudes are intrinsically similar to low‐degree modes, then their observed amplitudes must be significantly reduced.…”

Section: Discussionmentioning

confidence: 99%

First Kepler results on compact pulsators - V. Slowly pulsating subdwarf B stars in short-period binaries

Kawaler¹,

Reed²,

Østensen³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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The survey phase of the Kepler Mission includes a number of hot subdwarf B (sdB) stars to search for non‐radial pulsations. We present our analysis of two sdB stars that are found to be g‐mode pulsators of the V1093 Her class. These two stars also display the distinct irradiation effect typical of sdB stars with a close M‐dwarf companion with orbital periods of less than half a day. Because the orbital period is so short, the stars should be in synchronous rotation, and if so, the rotation period should imprint itself on the multiplet structure of the pulsations. However, we do not find clear evidence for such rotational splitting. Though the stars do show some frequency spacings that are consistent with synchronous rotation, they also display multiplets with splittings that are much smaller. Longer‐duration time series photometry will be needed to determine if those small splittings are in fact rotational splitting, or caused by slow amplitude or phase modulation. Further data should also improve the signal‐to‐noise ratio, perhaps revealing lower‐amplitude periodicities that could confirm the expectation of synchronous rotation. The pulsation periods seen in these stars show period spacings that are suggestive of high‐overtone g‐mode pulsations.

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Pulsating Stars in Close Binaries. I. Investigations of Eclipse Mapping and Oblique Pulsations

Cited by 47 publications

References 33 publications

Blue and yellow long-period variables in the direction of the Small Magellanic Cloud

Blue and yellow long-period variables in the direction of the Small Magellanic Cloud

An eclipsing post common-envelope system consisting of a pulsating hot subdwarf B star and a brown dwarf companion

First Kepler results on compact pulsators - V. Slowly pulsating subdwarf B stars in short-period binaries

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