The future evolution of white dwarf stars through baryon decay and time varying gravitational constant

AbstractI have collected all the WET archival data on the pulsating DB white dwarf stars (DBVs) and re-reduced them. In addition, the WET has recently observed three DBVs. Preliminary results on PG 1115+158, PG 1351+489, KUV 05134+2605, PG 1654+160 and PG 1456+103 are presented, and the future use of the data is outlined.

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An upper limit to the secular variation of the gravitational constant from white dwarf stars

Journal of Cosmology and Astroparticle Physics ◽

10.1088/1475-7516/2011/05/021 ◽

2011 ◽

Vol 2011 (05) ◽

pp. 021-021 ◽

Cited By ~ 29

Author(s):

Enrique García-Berro ◽

Pablo Lorén-Aguilar ◽

Santiago Torres ◽

Leandro G Althaus ◽

Jordi Isern

Keyword(s):

Secular Variation ◽

White Dwarf ◽

Gravitational Constant ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Upper Limit

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STELLAR FOOTPRINTS OF A VARIABLE G

Modern Physics Letters A ◽

10.1142/s0217732399001061 ◽

1999 ◽

Vol 14 (15) ◽

pp. 1007-1014 ◽

Cited By ~ 2

Author(s):

DIEGO F. TORRES

Keyword(s):

Gravitational Constant ◽

Energy Limit ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Astrophysical Objects ◽

Long Time ◽

Approaches To Study ◽

Methodological Approaches ◽

Varying Gravitational Constant ◽

Variable G

Theories with varying gravitational constant G have been studied long time ago. Among them, the most promising candidates as alternatives of the standard general relativity are known as scalar–tensor theories. They provide consistent descriptions of the observed universe and arise as the low energy limit of several pictures of unified interactions. Therefore, an increasing interest on the astrophysical consequences of such theories has been sparked over the last few years. In this letter we comment on two methodological approaches to study evolution of astrophysical objects within a varying-G theory, and the particular results we have obtained for boson and white dwarf stars.

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Constraining the secular variation of the gravitational constant using white-dwarf stars spectra

10.21203/rs.3.rs-566213/v1 ◽

2021 ◽

Author(s):

T. D. Le

Keyword(s):

White Dwarf ◽

Gravitational Constant ◽

Hubble Space Telescope ◽

Critical Role ◽

Dwarf Stars ◽

Gravitational Fields ◽

White Dwarf Stars ◽

Strong Gravitational Fields ◽

Imaging Spectrograph ◽

Fundamental Physical

Abstract Context Astrophysical observations play a critical role in the possibility of variations in fundamental physical constants. One of the ways of probing these variations would be based on the evolution of the white-dwarf stars. Aims We use the spectrum of white-dwarf star G191-B2B to find an upper limit on the possible deviation of the gravitational constant with strong gravitational fields. Methods We analyze archive observation of the Hubble Space Telescope Imaging Spectrograph (HSTIS) to determine the possible cosmological deviation of the gravitational constant from the observed gravitational redshift. Results Our analysis provided a strong estimate on an upper bound on the possible space-time variation of the gravitational constant ̇⁄ = (0.238 ± 2.959) × 10 yr comparing with previous results. Conclusions The obtained result in this study offers the possibility of testing parameters of modern unification theories.

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The Time Dependence of the Phases of the Harmonics Relative to the 1490 sec Fundamental in PG1346+082

International Astronomical Union Colloquium ◽

10.1017/s0252921100099759 ◽

1989 ◽

Vol 114 ◽

pp. 296-299

Author(s):

J. L. Provencal ◽

J. C. Clemens ◽

G. Henry ◽

B. P. Hine ◽

R. E. Nather ◽

...

Keyword(s):

White Dwarf ◽

Compact Object ◽

Detailed Knowledge ◽

Line Profiles ◽

Pressure Broadening ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Adequate Understanding ◽

Magnitude Variation ◽

Hydrogen Lines

White dwarf stars provide important boundary conditions for the understanding of stellar evolution. An adequate understanding of even these simple stars is impossible without detailed knowledge of their interiors. PG1346+082, an interacting binary white dwarf system, provides a unique opportunity to view the interior of one degenerate as it is brought to light in the accretion disk of the second star as the primary strips material from its less massive companion (see Wood et at. 1987).PG1346+082 is a photometric variable with a four magnitude variation over a four to five day quasi-period. A fast Fourier transform (FFT) of the light curve shows a complex, time-dependent structure of harmonics. PG1346+082 exhibits flickering – the signature of mass transfer. The optical spectra of the system contain weak emission features during minimum and broad absorption at all other times. This could be attributed to pressure broadening in the atmosphere of a compact object, or to a combination of pressure broadening and doppler broadening in a disk surrounding the compact accretor. No hydrogen lines are observed and the spectra are dominated by neutral helium. The spectra also display variable asymmetric line profiles.

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