Main-Sequence Masses and Radii from Gravitational Redshifts

Hippel, Ted von

doi:10.1086/309911

Cited by 5 publications

(3 citation statements)

References 22 publications

(17 reference statements)

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“…Recently, attention has been turned toward the verification of the predictions by direct analysis of the data [164,165]. Detected light carries crucial information on a wide variety of properties of sources, from mass-to-radius ratio [18,24], to magnetic fields [166]. Redshift in this context is usually considered from a classical perspective in the sense of ignoring the quantum properties of light.…”

Section: Neutrino Oscillationsmentioning

confidence: 99%

“…Light signals sent by the source at a given initial frequency are detected by the receiver with a different frequency as measured locally. More than one century after the formulation of the theory [1,5], gravitational redshift has been unequivocally established by experiments on Earth [6,7,8,9,10,11,12,13,14,15,16] as well as via astrophysical observations [17,18,19,20,21,22,23,24,25]. Different proposals have now been put forward for its exploitation in astrophysics [26], for quantum information related tasks [27], and for testing novel and fundamental theories of Nature [28].…”

Section: Introductionmentioning

confidence: 99%

“…After Soviet physicist Vladimir Aleksandrovich Fock (22 December 1898 -27 December 1974) 18. After Korean physicist Chung Ki Hong, Chinese-American physicist Zhe-Yu Jeff Ou, and American physicist Leonard Mandel (9 May 1927 -9 February 2001).…”

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confidence: 99%

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Introduction to gravitational redshift of quantum photons propagating in curved spacetime

Rodríguez

Schell

Bruschi

2023

J. Phys.: Conf. Ser.

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Gravitational redshift is discussed in the context of quantum photons propagating in curved spacetime. A brief introduction to modelling realistic photons is first presented and the effect of gravity on the spectrum computed for photons largely confined along the direction of propagation. It is then shown that redshift-induced transformations on photon operators with sharp momenta are not unitary, while a unitary transformation can be constructed for realistic photons with finite bandwidth. The unitary transformation obtained is then characterized as a multimode mixing operation, which is a generalized rotation of the Hilbert-space basis. Finally, applications of these results are discussed with focus on performance of quantum communication protocols, exploitation of the effects for quantum metrology and sensing, as well as potential for tests of fundamental science.

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Section: Neutrino Oscillationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Introduction to gravitational redshift of quantum photons propagating in curved spacetime

Rodríguez

Schell

Bruschi

2023

J. Phys.: Conf. Ser.

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Astrometric versus Spectroscopic Radial Velocities

Dravins

Gullberg

Lindegren

et al. 1999

International Astronomical Union Colloquium

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The apparent radial velocity of a star, as deduced from wavelength shifts, comprises not merely its true velocity, but also components arising from dynamics in the star’s atmosphere, gravitational redshift, and other effects. For the Sun, such phenomena can be segregated since the relative Sun-Earth motion is known from planetary system dynamics. This is now becoming possible also for other stars, whose true radial motions are determined through space astrometry. A study of the differences between accurate astrometric velocities (from Hipparcos), and precise spectroscopic values (from ELODIE) is in progress. Data for cool stars in the Hyades indicate a tendency of relative blueshifts among earlier main-sequence F-type stars, and in giants. This is theoretically expected: an increased convective blueshift due to the more vigorous convection in F-stars, and a decreased gravitational redshift in giants.

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Gravitational redshifts in main-sequence and giant stars

Pasquini

Melo

Chavero

et al. 2011

A&A

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Context. Precise analyses of stellar radial velocities is able to reveal intrinsic causes of the wavelength shifts of spectral lines (other than Doppler shifts due to radial motion), such as gravitational redshifts and convective blueshifts. Aims. Gravitational redshifts in solar-type main-sequence stars are expected to be some 500 m s −1 greater than those in giants. We search for this difference in redshifts among groups of open-cluster stars that share the same average space motion and thus have the same average Doppler shift. Methods. We observed 144 main-sequence stars and cool giants in the M 67 open cluster using the ESO FEROS spectrograph and obtained radial velocities by means of cross-correlation with a spectral template. Binaries and doubtful members were not analyzed, and average spectra were created for different classes of stars. Results. The M 67 dwarf and giant radial-velocity distributions are each well represented by Gaussian functions, which share the same apparent average radial velocity to within 100 m s −1 . In addition, dwarfs in M 67 appear to be dynamically hotter (σ = 0.90 km s −1 ) than giants (σ = 0.68 km s −1 ). Conclusions. We fail to detect any difference in the gravitational redshifts of giants and MS stars. This is probably because of the differential wavelength shifts produced by the different hydrodynamics of dwarf and giant atmospheres. Radial-velocity differences measured between unblended lines in averaged spectra vary with line-strength: stronger lines are more blueshifted in dwarfs than in giants, apparently removing any effect of the gravitational redshift. Synthetic high-resolution spectra are computed from three dimensional (3D) hydrodynamic model atmospheres for both giants and dwarfs, and synthetic wavelength shifts obtained. In agreement with observations, 3D models predict substantially smaller wavelength-shift differences than expected from gravitational redshifts only. The procedures developed could be used to test 3D models for different classes of stars, but will ultimately require high-fidelity spectra for measurements of wavelength shifts in individual spectral lines.

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Main-Sequence Masses and Radii from Gravitational Redshifts

Cited by 5 publications

References 22 publications

Introduction to gravitational redshift of quantum photons propagating in curved spacetime

Introduction to gravitational redshift of quantum photons propagating in curved spacetime

Astrometric versus Spectroscopic Radial Velocities

Gravitational redshifts in main-sequence and giant stars

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