Gravitational redshift and mass-radius relation in white dwarfs

1987 ◽  
Vol 322 ◽  
pp. 852 ◽  
Author(s):  
D. Koester
Keyword(s):  
White Dwarfs ◽  
Gravitational Redshift

Masses of DA white dwarfs with gravitational redshift determinations

1995 ◽  
Vol 444 ◽  
pp. 810 ◽  
Author(s):  
P. Bergeron ◽  
James Liebert ◽  
M. S. Fulbright
Keyword(s):  
White Dwarfs ◽  
Gravitational Redshift

Rate of losing energy in Quantum Redshift

2021 ◽  
Author(s):  
Bahram Kalhor ◽  
Farzaneh Mehrparvar ◽  
Behnam Kalhor
Keyword(s):  
Electromagnetic Waves ◽  
White Dwarfs ◽  
Average Rate ◽  
Gravitational Redshift ◽  
Space Theory ◽  
Carbon Stars ◽  
Space Objects ◽  
The Waves ◽  
Over Time ◽  
Expansion Of Space

Abstract The paper simulates the losing energy of the electromagnetic waves in a non-expansion space and no gravitational Redshift. We use the distance and Redshift of 93,060 nearby space objects, including stars, quasars, white dwarfs, and carbon stars, for obtaining the rate of losing the energy of their waves during traveling in space. Quantum Redshift disagrees expansion of space and describes Redshift by losing the energy of electromagnetic waves over time. In the Quantum Redshift, regardless of the material and type of the space objects (stars, quasars, white dwarfs, and carbon stars), the Redshift depends on the distance and temperature of the space objects, and the temperature of space. We have used SIMBAD Astronomical Database. We have retrieved this information from almost 2,200,000 records. The objects' temperature is between 671 and 99,575 K. The distance of the objects is between 413.13 and 0.5 (mas). The paper obtains the average rate of losing the waves' energy for different objects in different distances. The results show that by increasing the distance of space objects, the rate of losing the energy of their electromagnetic waves will be decreased. The paper inspires investigating the expansion space theory by the Quantum Redshift.

scholarly journals A GRAVITATIONAL REDSHIFT DETERMINATION OF THE MEAN MASS OF WHITE DWARFS. DA STARS

2010 ◽  
Vol 712 (1) ◽  
pp. 585-595 ◽  
Author(s):  
Ross E. Falcon ◽  
D. E. Winget ◽  
M. H. Montgomery ◽  
Kurtis A. Williams
Keyword(s):  
White Dwarfs ◽  
Gravitational Redshift ◽  
The Mean

scholarly journals Masses of the Hyades white dwarfs

2019 ◽  
Vol 627 ◽  
pp. L8 ◽  
Author(s):  
L. Pasquini ◽  
A. F. Pala ◽  
H.-G. Ludwig ◽  
I. C. Lẽao ◽  
J. R. de Medeiros ◽  
...  
Keyword(s):  
Radial Velocity ◽  
White Dwarfs ◽  
Velocity Dispersion ◽  
Open Clusters ◽  
Gravitational Redshift ◽  
Low Velocity ◽  
Hyades Cluster ◽  
The Masses ◽  
Good Agreement

Context. It is possible to accurately measure the masses of the white dwarfs (WDs) in the Hyades cluster using gravitational redshift, because the radial velocity of the stars can be obtained independently of spectroscopy from astrometry and the cluster has a low velocity dispersion. Aims. We aim to obtain an accurate measurement of the Hyades WD masses by determining the mass-to-radius ratio (M/R) from the observed gravitational redshift, and to compare them with masses derived from other methods. Methods. We analyse archive high-resolution UVES-VLT spectra of six WDs belonging to the Hyades to measure their Doppler shift, from which M/R is determined after subtracting the astrometric radial velocity. We estimate the radii using Gaia photometry as well as literature data. Results. The M/R error associated to the gravitational redshift measurement is about 5%. The radii estimates, evaluated with different methods, are in very good agreement, though they can differ by up to 4% depending on the quality of the data. The masses based on gravitational redshift are systematically smaller than those derived from other methods, by a minimum of ∼0.02 up to 0.05 solar masses. While this difference is within our measurement uncertainty, the fact that it is systematic indicates a likely real discrepancy between the different methods. Conclusions. We show that the M/R derived from gravitational redshift measurements is a powerful tool to determine the masses of the Hyades WDs and could reveal interesting properties of their atmospheres. The technique can be improved by using dedicated spectrographs, and can be extended to other clusters, making it unique in its ability to accurately and empirically determine the masses of WDs in open clusters. At the same time we prove that gravitational redshift in WDs agrees with the predictions of stellar evolution models to within a few percent.

scholarly journals Comparison between the Gravitational Redshift in the Kerr and Schwarzschild Fields

2021 ◽  
Author(s):  
Charles McGruder
Keyword(s):  
Neutron Stars ◽  
White Dwarfs ◽  
Gravitational Redshift ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Frame Dragging ◽  
Gravitational Fields ◽  
Significant Difference ◽  
Spherical Mass ◽  
Kerr Field

Abstract The Schwarzschild and Kerr metrics are solutions of Einstein field equations of general relativity representing the gravitational fields of a non-rotating spherical mass and a rotating black hole respectively. Unlike the Kerr field, the gravitational redshift in the Schwarzschild field is well known. We employ the concept of stationary clocks to derive the gravitational redshift in the Kerr field demonstrating that frame dragging plays no role. We then calculate the Kerr gravitational redshift for the earth, sun, white dwarfs and neutron stars and compare them with the Schwarzschild gravitational redshift, showing that the gravitational redshift on earth and from the sun does not differ from the Schwarzschild gravitational redshift. For extreme cases of rapidly rotating white dwarfs and neutron stars there is a significant difference between the two gravitational redshifts. Unlike the Schwarzschild gravitational redshift, the Kerr gravitational redshift has to date not been put on a firm observational basis. We point out that the gravitational redshift in the Kerr field possess a latitude dependency, which cannot be confirmed through solar or terrestrial observations, but can be on rapidly rotating white dwarfs and neutron stars

On the maximum gravitational redshift of white dwarfs

1976 ◽  
Vol 203 ◽  
pp. 697 ◽  
Author(s):  
S. L. Shapiro ◽  
S. A. Teukolsky
Keyword(s):  
White Dwarfs ◽  
Gravitational Redshift

scholarly journals A Gravitational Redshift Determination of the Mean Mass of DBA White Dwarfs

2010 ◽  
Author(s):  
Ross E. Falcon ◽  
D. E. Winget ◽  
M. H. Montgomery ◽  
Kurtis A. Williams ◽  
Klaus Werner ◽  
...  
Keyword(s):  
White Dwarfs ◽  
Gravitational Redshift ◽  
The Mean

scholarly journals PRESSURE SHIFT AND GRAVITATIONAL REDSHIFT OF BALMER LINES IN WHITE DWARFS: REDISCUSSION

2015 ◽  
Vol 808 (2) ◽  
pp. 131 ◽  
Author(s):  
Jacek Halenka ◽  
Wieslaw Olchawa ◽  
Jerzy Madej ◽  
Boleslaw Grabowski
Keyword(s):  
White Dwarfs ◽  
Gravitational Redshift ◽  
Pressure Shift ◽  
Balmer Lines

scholarly journals Perspective acceleration and gravitational redshift. Measuring masses of individual white dwarfs using Gaia + SIM astrometry

2009 ◽  
Vol 5 (S261) ◽  
pp. 342-344 ◽  
Author(s):  
Guillem Anglada-Escudé ◽  
John Debes
Keyword(s):  
Radial Velocity ◽  
White Dwarfs ◽  
Compact Objects ◽  
Gravitational Redshift ◽  
Great Precision ◽  
Nearby Star ◽  
Nasa Mission ◽  
New Situation ◽  
Better Than

AbstractAccording to current plans, the SIM/NASA mission will be launched just after the end of operations for the Gaia/ESA mission. This is a new situation which enables long term astrometric projects that could not be achieved by either mission alone. Using the well-known perspective acceleration effect on astrometric measurements, the true heliocentric radial velocity of a nearby star can be measured with great precision if the time baseline of the astrometric measurements is long enough. Since white dwarfs are compact objects, the gravitational redshift can be quite large (40–80 km/s), and is the predominant source of any shift in wavelength. The mismatch of the true radial velocity with the spectroscopic shift thus leads to a direct measure of the Mass–Radius relation for such objects. Using available catalog information about the known nearby white dwarfs, we estimate how many masses/gravitational redshift measurements can be obtained with an accuracy better than 2%. Nearby white dwarfs are relatively faint objects (10 < V < 15), which can be easily observed by both missions. We also briefly discuss how the presence of a long period planet can mask the astrometric signal of perspective acceleration.

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