Discovery of a new class of pulsating stars: Gravity-mode pulsators among subdwarf B stars

E. M. Green; G. Fontaine; M. D. Reed; K. Callerame; I. R. Seitenzahl; B. A. White; E. A. Hyde; R. Østensen; O. Cordes; P. Brassard; S. Falter; E. J. Jeffery; S. Dreizler; S. L. Schuh; M. Giovanni; H. Edelmann; J. Rigby; A. Bronowska

doi:10.1086/367929

Discovery of a new class of pulsating stars: Gravity-mode pulsators among subdwarf B stars

E. M. Green, G. Fontaine, M. D. Reed, K. Callerame, I. R. Seitenzahl, B. A. White, E. A. Hyde, R. Østensen, O. Cordes, P. Brassard, S. Falter, E. J. Jeffery, S. Dreizler, S. L. Schuh, M. Giovanni, H. Edelmann, J. Rigby, A. Bronowska

Steward Observatory

Research output: Contribution to journal › Article › peer-review

230 Scopus citations

Abstract

During the course of an ongoing CCD monitoring program to investigate low-level light variations in subdwarf B (sdB) stars, we have serendipitously discovered a new class of low-amplitude, multimode sdB pulsators with periods of the order of an hour. These periods are more than a factor of 10 longer than those of previously known multimode sdB pulsators (EC 14026 stars), implying that they are due to gravity modes rather than pressure modes. The longer period pulsators are found only among cooler sdB stars, where they are surprisingly common. The iron opacity instability that drives the short-period EC 14026 stars is effective only in hot sdB stars, leaving the driving mechanism for the deeper gravity modes in cool sdB stars currently unknown. We present the first observational results for our newly identified sdB variables and discuss possible implications.

Original language	English (US)
Pages (from-to)	L31-L34
Journal	Astrophysical Journal
Volume	583
Issue number	1 II
DOIs	https://doi.org/10.1086/367929
State	Published - Jan 20 2003

Keywords

Stars: horizontal-branch
Stars: oscillations
Subdwarfs

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/367929

Cite this

Green, E. M., Fontaine, G., Reed, M. D., Callerame, K., Seitenzahl, I. R., White, B. A., Hyde, E. A., Østensen, R., Cordes, O., Brassard, P., Falter, S., Jeffery, E. J., Dreizler, S., Schuh, S. L., Giovanni, M., Edelmann, H., Rigby, J., & Bronowska, A. (2003). Discovery of a new class of pulsating stars: Gravity-mode pulsators among subdwarf B stars. Astrophysical Journal, 583(1 II), L31-L34. https://doi.org/10.1086/367929

Green, EM, Fontaine, G, Reed, MD, Callerame, K, Seitenzahl, IR, White, BA, Hyde, EA, Østensen, R, Cordes, O, Brassard, P, Falter, S, Jeffery, EJ, Dreizler, S, Schuh, SL, Giovanni, M, Edelmann, H, Rigby, J & Bronowska, A 2003, 'Discovery of a new class of pulsating stars: Gravity-mode pulsators among subdwarf B stars', Astrophysical Journal, vol. 583, no. 1 II, pp. L31-L34. https://doi.org/10.1086/367929

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title = "Discovery of a new class of pulsating stars: Gravity-mode pulsators among subdwarf B stars",

abstract = "During the course of an ongoing CCD monitoring program to investigate low-level light variations in subdwarf B (sdB) stars, we have serendipitously discovered a new class of low-amplitude, multimode sdB pulsators with periods of the order of an hour. These periods are more than a factor of 10 longer than those of previously known multimode sdB pulsators (EC 14026 stars), implying that they are due to gravity modes rather than pressure modes. The longer period pulsators are found only among cooler sdB stars, where they are surprisingly common. The iron opacity instability that drives the short-period EC 14026 stars is effective only in hot sdB stars, leaving the driving mechanism for the deeper gravity modes in cool sdB stars currently unknown. We present the first observational results for our newly identified sdB variables and discuss possible implications.",

keywords = "Stars: horizontal-branch, Stars: oscillations, Subdwarfs",

author = "Green, {E. M.} and G. Fontaine and Reed, {M. D.} and K. Callerame and Seitenzahl, {I. R.} and White, {B. A.} and Hyde, {E. A.} and R. {\O}stensen and O. Cordes and P. Brassard and S. Falter and Jeffery, {E. J.} and S. Dreizler and Schuh, {S. L.} and M. Giovanni and H. Edelmann and J. Rigby and A. Bronowska",

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doi = "10.1086/367929",

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T1 - Discovery of a new class of pulsating stars

T2 - Gravity-mode pulsators among subdwarf B stars

AU - Green, E. M.

AU - Fontaine, G.

AU - Reed, M. D.

AU - Callerame, K.

AU - Seitenzahl, I. R.

AU - White, B. A.

AU - Hyde, E. A.

AU - Østensen, R.

AU - Cordes, O.

AU - Brassard, P.

AU - Falter, S.

AU - Jeffery, E. J.

AU - Dreizler, S.

AU - Schuh, S. L.

AU - Giovanni, M.

AU - Edelmann, H.

AU - Rigby, J.

AU - Bronowska, A.

PY - 2003/1/20

Y1 - 2003/1/20

N2 - During the course of an ongoing CCD monitoring program to investigate low-level light variations in subdwarf B (sdB) stars, we have serendipitously discovered a new class of low-amplitude, multimode sdB pulsators with periods of the order of an hour. These periods are more than a factor of 10 longer than those of previously known multimode sdB pulsators (EC 14026 stars), implying that they are due to gravity modes rather than pressure modes. The longer period pulsators are found only among cooler sdB stars, where they are surprisingly common. The iron opacity instability that drives the short-period EC 14026 stars is effective only in hot sdB stars, leaving the driving mechanism for the deeper gravity modes in cool sdB stars currently unknown. We present the first observational results for our newly identified sdB variables and discuss possible implications.

AB - During the course of an ongoing CCD monitoring program to investigate low-level light variations in subdwarf B (sdB) stars, we have serendipitously discovered a new class of low-amplitude, multimode sdB pulsators with periods of the order of an hour. These periods are more than a factor of 10 longer than those of previously known multimode sdB pulsators (EC 14026 stars), implying that they are due to gravity modes rather than pressure modes. The longer period pulsators are found only among cooler sdB stars, where they are surprisingly common. The iron opacity instability that drives the short-period EC 14026 stars is effective only in hot sdB stars, leaving the driving mechanism for the deeper gravity modes in cool sdB stars currently unknown. We present the first observational results for our newly identified sdB variables and discuss possible implications.

KW - Stars: horizontal-branch

KW - Stars: oscillations

KW - Subdwarfs

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JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1 II

ER -

Discovery of a new class of pulsating stars: Gravity-mode pulsators among subdwarf B stars

Abstract

Keywords

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