The Mass and Radius of 40 Eridani B from [ITAL]HIPPARCOS[/ITAL]: An Accurate Test of Stellar Interior Theory

Shipman, H. L.; Provencal, J. L.; Høg, E.; Thejll, Peter

doi:10.1086/310909

Cited by 28 publications

(18 citation statements)

References 20 publications

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“…This is the mass-radius relationship. It is possible to extrapolate both M star and R from astronomical data, for example see [99,100,101]. In all of those works, and others like them, the mass-radius relationship, as predicted by General Relativity , has been found to be in good agreement with the data.…”

Section: Implications For Compact Bodiesmentioning

confidence: 75%

Evading equivalence principle violations, cosmological, and other experimental constraints in scalar field theories with a strong coupling to matter

2007

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We show that, as a result of non-linear self-interactions, it is feasible, at least in light of the bounds coming from terrestrial tests of gravity, measurements of the Casimir force and those constraints imposed by the physics of compact objects, big-bang nucleosynthesis and measurements of the cosmic microwave background, for there to exist, in our Universe, one or more scalar fields that couple to matter much more strongly than gravity does. These scalar fields behave like chameleons: changing their properties to fit their surroundings. As a result these scalar fields can be not only very strongly coupled to matter, but also remain relatively light over solar system scales. These fields could also be detected by a number of future experiments provided they are properly designed to do so. These results open up an altogether new window, which might lead to a completely different view of the rôle played by light scalar fields in particle physics and cosmology.PACS numbers: 98.80.-k,98.80.Jk

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Section: Implications For Compact Bodiesmentioning

confidence: 75%

Evading equivalence principle violations, cosmological, and other experimental constraints in scalar field theories with a strong coupling to matter

2007

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“…With the aim of comparing with astrophysical data, in Table 1 we show ten dwarf stars collected by the catalogs reported in Refs. [36][37][38], mainly emphasizing the values of mass, radius, and central density; then for the samples of Table 1 and under the assumption that the observed white dwarfs must belong to a family of equilibrium configuration without an anomalous behavior, the average value of the brane tension must be λ 84.818 MeV 4 , with a standard deviation σ 82.021 MeV 4 , showing too much dispersion in the set of the sample. This is attributed to the marked differences between the dwarf stars.…”

Section: Results Of the Numerical Solutionsmentioning

confidence: 99%

Branes constrictions with White Dwarfs

García‐Aspeitia

2015

Eur. Phys. J. C

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We consider here a robust study of stellar dynamics for white dwarf stars with polytropic matter in the weakfield approximation using the Lane-Emden equation from the brane-world scenario. We also derive an analytical solution to the nonlocal energy density and show the behavior and sensitivity of these stars to the presence of extra dimensions. Similarly, we analyze stability and compactness, in order to show whether it is possible to agree with the conventional wisdom of white dwarfs dynamics. Our results predict an average value of the brane tension of λ 84.818 MeV 4 , with a standard deviation σ 82.021 MeV 4 , which comes from a sample of dwarf stars, being weaker than other astrophysical observations but remaining higher than cosmological results provided by nucleosynthesis among others.

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“…Thus, before our eyes so to speak there is the "dark matter" and a fascinating prospect for future research along this line! 28 As we have demonstrated in Bernkopf et al (2001) with the nearby bona fide thick-disk cool white dwarfs 27 For a concrete example of two famous white dwarfs we mention the nearby Sirius B and o 2 Eri B: the latter has M = 0.501 ± 0.011 M and R = 0.0136 ± 0.00024 R according to Shipman et al (1997), whereas Sirius B is more massive, M = 1.034 ± 0.026 M , and hence much smaller R = 0.0084 ± 0.00025 R (Holberg et al 1998). 28 Another, even cooler, nearby white dwarf CE 51 (=LHS 2068, V=18.07) was also recently uncovered by Ruiz & Bergeron (2001), inset at the upper left) that was only recently detected by Scholz et al (2002).…”

Section: Initial Mass Function and Luminosity Functionmentioning

confidence: 85%

“…This is because the dynamical mass, M W D = 0.501 ± 0.011 M , is the most accurately determined for any degenerate (Shipman et al 1997), and this white dwarf mass in turn is very close to the low mass cut-off for single star evolution that is possible within the time span of the Milky Way (cf. Weidemann & Koester 1983, Renzini & Fusi Pecci 1988, Bragaglia, Renzini, & Bergeron 1995 104 Tau: there is some contradicting information in the literature as to whether this star is a visual binary or not.…”

Section: Notes On Individual Starsmentioning

confidence: 88%

Nearby stars of the Galactic disk and halo. III.

2003

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Abstract. High-resolution spectroscopic observations of about 150 nearby stars or star systems are presented and discussed. The study of these and another 100 objects of the previous papers of this series implies that the Galaxy became reality 13 or 14 Gyr ago with the implementation of a massive, rotationally-supported population of thick-disk stars. The very high star formation rate in that phase gave rise to a rapid metal enrichment and an expulsion of gas in supernovae-driven Galactic winds, but was followed by a star formation gap for no less than three billion years at the Sun's galactocentric distance. In a second phase, then, the thin disk -our "familiar Milky Way" -came on stage. Nowadays it traces the bright side of the Galaxy, but it is also embedded in a huge coffin of dead thick-disk stars that account for a large amount of baryonic dark matter. As opposed to this, cold-dark-matter-dominated cosmologies that suggest a more gradual hierarchical buildup through mergers of minor structures, though popular, are a poor description for the Milky Way Galaxy -and by inference many other spirals as well -if, as the sample implies, the fossil records of its long-lived stars do not stick to this paradigm. Apart from this general picture that emerges with reference to the entire sample stars, a good deal of the present work is however also concerned with detailed discussions of many individual objects. Among the most interesting we mention the blue straggler or merger candidates HD 165401 and HD 137763/HD 137778, the likely accretion of a giant planet or brown dwarf on 59 Vir in its recent history, and HD 63433 that proves to be a young solar analog at τ ∼ 200 Myr. Likewise, the secondary to HR 4867, formerly suspected non-single from the Hipparcos astrometry, is directly detectable in the highresolution spectroscopic tracings, whereas the visual binary χ Cet is instead at least triple, and presumably even quadruple. With respect to the nearby young stars a complete account of the Ursa Major Association is presented, and we provide as well plain evidence for another, the "Hercules-Lyra Association", the likely existence of which was only realized in recent years. On account of its rotation, chemistry, and age we do confirm that the Sun is very typical among its G-type neighbors; as to its kinematics, it appears however not unlikely that the Sun's known low peculiar space velocity could indeed be the cause for the weak paleontological record of mass extinctions and major impact events on our parent planet during the most recent Galactic plane passage of the solar system. Although the significance of this correlation certainly remains a matter of debate for years to come, we point in this context to the principal importance of the thick disk for a complete census with respect to the local surface and volume densities. Other important effects that can be ascribed to this dark stellar population comprise (i) the observed plateau in the shape of the luminosity function of the local FGK stars, (ii) a small though syst...

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The Mass and Radius of 40 Eridani B from [ITAL]HIPPARCOS[/ITAL]: An Accurate Test of Stellar Interior Theory

Cited by 28 publications

References 20 publications

Evading equivalence principle violations, cosmological, and other experimental constraints in scalar field theories with a strong coupling to matter

Evading equivalence principle violations, cosmological, and other experimental constraints in scalar field theories with a strong coupling to matter

Branes constrictions with White Dwarfs

Nearby stars of the Galactic disk and halo. III.

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