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

Mapping Intimacies ◽

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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Hubble Space Telescope Observations of White Dwarf Stars

White Dwarfs: Advances in Observation and Theory ◽

10.1007/978-94-011-2020-3_39 ◽

1993 ◽

pp. 295-302

Author(s):

Harry L. Shipman ◽

Maurice Barnhill ◽

Howard Bond ◽

Fred Bruhweiler ◽

David Finley ◽

...

Keyword(s):

White Dwarf ◽

Hubble Space Telescope ◽

Dwarf Stars ◽

Space Telescope ◽

White Dwarf Stars

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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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A far-UV survey of three hot, metal-polluted white dwarf stars: WD0455−282, WD0621−376, and WD2211−495

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1506 ◽

2019 ◽

Vol 487 (3) ◽

pp. 3470-3487 ◽

Cited By ~ 2

Author(s):

Simon P Preval ◽

Martin A Barstow ◽

Matthew Bainbridge ◽

Nicole Reindl ◽

Thomas Ayres ◽

...

Keyword(s):

White Dwarf ◽

White Dwarfs ◽

Hubble Space Telescope ◽

Line Of Sight ◽

Hot Metal ◽

Dwarf Stars ◽

High Resolution Data ◽

White Dwarf Stars ◽

Order Of Magnitude ◽

Far Ultraviolet

ABSTRACT Using newly obtained high-resolution data (R ∼ 1 × 105) from the Hubble Space Telescope, and archival UV data from the Far Ultraviolet Spectroscopic Explorer, we have conducted a detailed UV survey of the three hot, metal-polluted white dwarfs WD0455−282, WD0621−376, and WD2211−495. Using bespoke model atmospheres, we measured Teff, log g, and photospheric abundances for these stars. In conjunction with data from Gaia, we measured masses, radii, and gravitational redshift velocities for our sample of objects. We compared the measured photospheric abundances with those predicted by radiative levitation theory, and found that the observed Si abundances in all three white dwarfs, and the observed Fe abundances in WD0621−376 and WD2211−495, were larger than those predicted by an order of magnitude. These findings imply not only an external origin for the metals, but also ongoing accretion, as the metals not supported by radiative levitation would sink on extremely short time-scales. We measured the radial velocities of several absorption features along the line of sight to the three objects in our sample, allowing us to determine the velocities of the photospheric and interstellar components along the line of sight for each star. Interestingly, we made detections of circumstellar absorption along the line of sight to WD0455−282 with three velocity components. To our knowledge, this is the first such detection of multicomponent circumstellar absorption along the line of sight to a white dwarf.

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Hubble Space Telescope observations of cool white dwarf stars: Detection of new species of heavy elements

The Astronomical Journal ◽

10.1086/117356 ◽

1995 ◽

Vol 109 ◽

pp. 1231 ◽

Cited By ~ 4

Author(s):

H. L. Shipman ◽

M. Barnhill ◽

J. Provencal ◽

S. Roby ◽

I. Bues ◽

...

Keyword(s):

New Species ◽

White Dwarf ◽

Hubble Space Telescope ◽

Heavy Elements ◽

Dwarf Stars ◽

Space Telescope ◽

White Dwarf Stars

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

Astrophysics and Space Science ◽

10.1007/s10509-008-9878-4 ◽

2008 ◽

Vol 317 (3-4) ◽

pp. 221-230 ◽

Cited By ~ 1

Author(s):

Jacob A. Ketchum ◽

Fred C. Adams

Keyword(s):

White Dwarf ◽

Gravitational Constant ◽

Time Varying ◽

Dwarf Stars ◽

Future Evolution ◽

White Dwarf Stars ◽

Baryon Decay ◽

The Future ◽

Varying Gravitational Constant

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H–He collision-induced satellite in the Lyman α profile of DBA white dwarf stars

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa707 ◽

2020 ◽

Vol 494 (1) ◽

pp. 868-875 ◽

Cited By ~ 1

Author(s):

Nicole F Allard ◽

John F Kielkopf ◽

Siyi Xu ◽

Grégoire Guillon ◽

Bilel Mehnen ◽

...

Keyword(s):

Ab Initio ◽

White Dwarf ◽

Hubble Space Telescope ◽

Spectral Lines ◽

Absorption Feature ◽

Atomic Interaction ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Atomic Interactions ◽

Rigorous Treatment

ABSTRACT The spectra of helium-dominated white dwarf stars with hydrogen in their atmosphere present a distinctive broad feature centred around 1160 Å in the blue wing of the Lyman α line. It is extremely apparent in WD 1425+540 recently observed with Hubble Space Telescope(HST) Cosmic Origins Spectrograph (COS). With new theoretical line profiles based on ab initio atomic interaction potentials we show that this feature is a signature of a collision-induced satellite due to an asymptotically forbidden transition. This quasi-molecular spectral satellite is crucial to understanding the asymmetrical shape of Lyman α seen in this and other white dwarf spectra. Our previous work predicting this absorption feature was limited by molecular potentials that were not adequate to follow the atomic interactions with spectroscopic precision to the asymptotic limit of large separation. A new set of potential energy curves and electronic dipole transition moments for the lowest electronic states of the H–He system were developed to account accurately for the behaviour of the atomic interactions at all distances, from the chemical regime within 1 Å out to where the radiating H atoms are not significantly perturbed by their neighbours. We use a general unified theory of collision-broadened atomic spectral lines to describe a rigorous treatment of hydrogen Lyman α with these potentials and present a new study of its broadening by radiative collisions of hydrogen and neutral helium. These results enable ab initio modelling of radiative transport in DBA white dwarf atmospheres.

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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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