Discovery and analysis of p-mode and g-mode oscillations in the A-type primary of the eccentric binary HD 209295⋆

Handler, G.; Balona, L. A.; Shobbrook, R. R.; Koen, C.; Bruch, A.; Romero-Colmenero, E.; Pamyatnykh, A. A.; Willems, Bart; Eyer, L.; James, D. J.; Maas, T.

doi:10.1046/j.1365-8711.2002.05295.x

Cited by 130 publications

(78 citation statements)

References 49 publications

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“…respectively. This leads us to speculate that they may both represent tidally excited non-radial oscillation modes (see also Willems & Aerts 2002;Handler et al 2002).…”

Section: Tidally Induced Non-radial Oscillationsmentioning

confidence: 94%

The mass of the neutron star in Vela X-1 and tidally induced non-radial oscillations in GP Vel

Quaintrell

Norton

Ash

et al. 2003

A&A

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181

153

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Abstract. We report new radial velocity observations of GP Vel / HD 77581, the optical companion to the eclipsing X-ray pulsar Vela X-1. Using data spanning more than two complete orbits of the system, we detect evidence for tidally induced nonradial oscillations on the surface of GP Vel, apparent as peaks in the power spectrum of the residuals to the radial velocity curve fit. By removing the effect of these oscillations (to first order) and binning the radial velocities, we have determined the semiamplitude of the radial velocity curve of GP Vel to be K o = 22.6 ± 1.5 km s −1 . Given the accurately measured semi-amplitude of the pulsar's orbit, the mass ratio of the system is 0.081 ± 0.005. We are able to set upper and lower limits on the masses of the component stars as follows. Assuming GP Vel fills its Roche lobe then the inclination angle of the system, i, is 70.1• ± 2.6• . In this case we obtain the masses of the two stars as M x = 2.27 ± 0.17 M for the neutron star and M o = 27.9 ± 1.3 M for GP Vel. Conversely, assuming the inclination angle is i = 90• , the ratio of the radius of GP Vel to the radius of its Roche lobe is β = 0.89 ± 0.03 and the masses of the two stars are M x = 1.88 ± 0.13 M and M o = 23.1 ± 0.2 M . A range of solutions between these two sets of limits is also possible, corresponding to other combinations of i and β. In addition, we note that if the zero phase of the radial velocity curve is allowed as a free parameter, rather than constrained by the X-ray ephemeris, a significantly improved fit is obtained with an amplitude of 21.2 ± 0.7 km s −1 and a phase shift of 0.033 ± 0.007 in true anomaly. The apparent shift in the zero phase of the radial velocity curve may indicate the presence of an additional radial velocity component at the orbital period. This may be another manifestation of the tidally induced non-radial oscillations and provides an additional source of uncertainty in the determination of the orbital radial velocity amplitude.

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“…respectively. This leads us to speculate that they may both represent tidally excited non-radial oscillation modes (see also Willems & Aerts 2002;Handler et al 2002).…”

Section: Tidally Induced Non-radial Oscillationsmentioning

confidence: 94%

The mass of the neutron star in Vela X-1 and tidally induced non-radial oscillations in GP Vel

Quaintrell

Norton

Ash

et al. 2003

A&A

Self Cite

181

153

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“…The class of γ Dor / δ Scu hybrids are discussed in Handler et al (2002), Dupret et al (2005), and Henry & Fekel (2005).…”

Section: Implications For Asteroseismologymentioning

confidence: 99%

HS 0702+6043: a star showing both short-period p-mode and long-period g-mode oscillations

Schuh¹,

Huber²,

Dreizler³

et al. 2006

A&A

112

106

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Context. The hot subdwarf B star HS 0702+6043 is known as a large-amplitude, short-period p-mode pulsator of the EC 14026 type. Its atmospheric parameters place it at the common boundary between the empirical instability regions of the EC 14026 variables and the typically cooler long-period g-mode pulsators of the PG 1716 kind. Aims. We analyse and interpret the photometric variability of HS 0702+6043 in order to explore its asteroseismological potential. Methods. We report on rapid wide band CCD photometric observations to follow up on and confirm the serendipitous discovery of multiperiodic long-period luminosity variations with typical time scales of ∼1 h in HS 0702+6043, in addition to the two previously known pulsations at 363 s and 383 s. In particular, we isolate a relatively low-amplitude (∼4 mmag), long-period (3538 ± 130 s) light variation. Results. We argue that the most likely origin for this luminosity variation is the presence of an excited g-mode pulsation. If confirmed, HS 0702+6043 would constitute a rare addition to the very select class of pulsating stars showing simultaneously parts of their pressure and gravity mode pulsation spectra. The asteroseismological potential of such stars is immense, and HS 0702+6043 thus becomes a target of choice for future investigations. While our discovery appears consistent with the location of HS 0702+6043 at the common boundary between the two families of pulsating sdB stars, it does challenge theory's current description of stability and driving mechanisms in pulsating B subdwarfs.

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“…The examples of stars in which tidally induced pulsations were found are: δ Sct/γ Dor star HD209295 ( [32]), the SPB star HD177863 ( [33], [34]. There are also such pulsations detected from the CoRoT and/or Kepler photometry.…”

Section: Tidal Effects In Binary Systemsmentioning

confidence: 99%

Energetic properties of stellar pulsations across the Hertzsprung-Russell diagram

Daszyńska‐Daszkiewicz

2015

EPJ Web of Conferences

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Discovery and analysis of p-mode and g-mode oscillations in the A-type primary of the eccentric binary HD 209295⋆

Cited by 130 publications

References 49 publications

The mass of the neutron star in Vela X-1 and tidally induced non-radial oscillations in GP Vel

The mass of the neutron star in Vela X-1 and tidally induced non-radial oscillations in GP Vel

HS 0702+6043: a star showing both short-period p-mode and long-period g-mode oscillations

Energetic properties of stellar pulsations across the Hertzsprung-Russell diagram

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