A new class of rapidly pulsating star -- I. EC 14026 -- 2647, the class prototype

Kilkenny, D.; Koen, C.; O’Donoghue, D.; Stobie, R. S.

doi:10.1093/mnras/285.3.640

Cited by 407 publications

(309 citation statements)

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“…The existence of pulsating sdB stars was predicted theoretically by Charpinet et al (1996) ; subsequent observations by Kilkenny et al (1997) of a binary sdB star, EC 14026[2647, proved their existence. More pulsating sdB stars were soon found (see OÏDonoghue et al 1999 and references therein), and the class is now referred to as EC 14026 stars or sdBV stars.…”

Section: Pulsating Subdwarfsmentioning

confidence: 99%

Flash Mixing on the White Dwarf Cooling Curve: Understanding Hot Horizontal Branch Anomalies in NGC 2808

Brown

Sweigart

Lanz

et al. 2001

ApJ

197

394

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We present an ultraviolet color-magnitude diagram (CMD) spanning the hot horizontal branch (HB), blue straggler, and white dwarf populations of the globular cluster NGC 2808. These data were obtained with the far-UV and near-UV cameras on the Space Telescope Imaging Spectrograph (STIS). Although previous optical CMDs of NGC 2808 show a high-temperature gap within the hot HB population, no such gap is evident in our UV CMD. Instead, we Ðnd a population of hot subluminous HB stars, an anomaly only previously reported for the globular cluster u Cen. Our theoretical modeling indicates that the location of these subluminous stars in the UV CMD, as well as the high-temperature gap along the HB in optical CMDs, can be explained if these stars underwent a late helium-core Ñash while descending the white dwarf cooling curve. We show that the convection zone produced by such a late helium Ñash will penetrate into the hydrogen envelope, thereby mixing hydrogen into the hot helium-burning interior, where it is rapidly consumed. This phenomenon is analogous to the "" born again ÏÏ scenario for producing hydrogen-deÐcient stars following a late helium-shell Ñash. The Ñash mixing of the envelope greatly enhances the envelope helium and carbon abundances, and leads, in turn, to a discontinuous increase in the HB e †ective temperatures at the transition between canonical and Ñash-mixed stars. We argue that the hot HB gap is associated with this theoretically predicted dichotomy in the HB properties. Moreover, the changes in the emergent spectral energy distribution caused by these abundance changes are primarily responsible for explaining the hot subluminous HB stars. Although further evidence is needed to conÐrm that a late helium-core Ñash can account for the subluminous HB stars and the hot HB gap, we demonstrate that an understanding of these stars requires the use of appropriate theoretical models for their evolution, atmospheres, and spectra.

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Section: Pulsating Subdwarfsmentioning

confidence: 99%

Flash Mixing on the White Dwarf Cooling Curve: Understanding Hot Horizontal Branch Anomalies in NGC 2808

Brown

Sweigart

Lanz

et al. 2001

ApJ

197

394

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“…The group seemingly has, so far, no name, though SubDued BumPers comes to mind. Actually, it is amazing that Kilkenny et al (1997) did not suggest something of the sort, given the originality of their section titles (beginning with Comedy of Errors).…”

Section: Pulsators: Predictable and Otherwisementioning

confidence: 99%

Astrophysics in 1997

Trimble¹,

McFadden²

1998

PUBL ASTRON SOC PAC

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ABSTRACT. Martian marvels, a gamma-ray burster with a redshift, Galileo converses with Ganymede, a record galactic redshift of 4.92, and much else. Fiscal 1997 was definitely an exciting year for astronomers. We have tried hard to hit all the obvious highlights, but also to report more gradual progress on traditional problems of understanding planets, stars, galaxies, and the universe. Though the year was saddened by the loss of many valued colleagues, we nevertheless indulge in occasional soupçons of frivolity.

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“…The prototype for this class, EC 14026-2647, was observed by Kilkenny et al (1997) as part of the EdinburghCape (EC) survey (Stobie et al 1997b). They found the star to be pulsating with a period of 144 s (ν = 600 d −1 ; 6944 µHz) and an amplitude of 12 millimagnitudes (mmag).…”

Section: Introductionmentioning

confidence: 99%

Three new pulsating sdB stars discovered with SuperWASP

Holdsworth

Østensen

Smalley

et al. 2017

Mon. Not. R. Astron. Soc.

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We present an analysis of three new pulsating subdwarf B stars discovered in the SuperWASP archive. Two of the stars, J1938+5609 and J0902-0720, are p-mode pulsators; J1938+5609 shows a pulsation at 231.62 d −1 (P = 373 s; 2681 µHz) with an amplitude of 4 mmag, whereas J0902-0720 pulsates at frequencies 636.74 d −1 (P = 136 s; 7370 µHz) and 615.34 d −1 (P = 140 s; 7122 µHz), with amplitudes 7.27 and 1.53 mmag, respectively. The third star, J2344-3427, is a hybrid pulsator with a p-mode frequency at 223.16 d −1 (P = 387 s; 2583µHz) and a corresponding amplitude of 1.5 mmag, and g modes in the frequency range 8.68 − 28.56 d −1 (P = 3025 − 9954 s; 100 − 331µHz) and amplitudes between 0.76 and 1.17 mmag. Spectroscopic results place J1938+5609 and J2344-3427 among the long-period or hybrid pulsators, suggesting there may be further modes in these stars below our detection limits, with J0902-0720 placed firmly amongst the p-mode pulsators.

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A new class of rapidly pulsating star -- I. EC 14026 -- 2647, the class prototype

Cited by 407 publications

References 0 publications

Flash Mixing on the White Dwarf Cooling Curve: Understanding Hot Horizontal Branch Anomalies in NGC 2808

Flash Mixing on the White Dwarf Cooling Curve: Understanding Hot Horizontal Branch Anomalies in NGC 2808

Astrophysics in 1997

Three new pulsating sdB stars discovered with SuperWASP

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