Proxima’s orbit around <i>α</i> Centauri

Kervella, P.; Thévenin, F.; Lovis, C.

doi:10.1051/0004-6361/201629930

Cited by 98 publications

(129 citation statements)

References 57 publications

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“…Wertheimer & Laughlin (2006) calculated the binding energy of the wide pair AB,C and found that it can be either positive or negative with roughly equal probability. The latest study by Kervella et al (2017), however, shows that the triple system is bound and that the eccentricity of the outer orbit is moderate, 0.42. Therefore this triple system has not been formed by unfolding.…”

Section: Unfoldingmentioning

confidence: 97%

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Formation of wide binary stars from adjacent cores

Tokovinin¹

2017

Monthly Notices of the Royal Astronomical Society

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Wide gravitationally bound pairs of stars can be formed from adjacent prestellar cores that happen to move slowly enough relative to each other. These binaries are remnants of the primordial clustering. It is shown that the expected fraction of wide bound pairs in low-density star formation regions can be larger than the fraction of wide pairs in the field. On the other hand, wide binaries do not form or survive in dense clusters. Recent works on the separation distribution of young binaries, summarized here, confirm these expectations. Alternative formation mechanisms of wide binaries such as cluster dissolution or unfolding of triple stars cannot explain the large observed fraction of young wide pairs and therefore are not dominant. The fact that more than a half of wide pairs contain subsystems matches the general multiplicity statistics and does not imply that hierarchical multiplicity and wide binaries are genetically related.

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Section: Unfoldingmentioning

confidence: 97%

“…Wide binaries move so slowly that it is extremely difficult or impossible to test observationally whether they are gravitationally bound or just have common spatial motion and distance (Proxima Cen is a good example, Kervella et al 2017). Frequent occurrence of subsystems further complicates such tests.…”

Section: Introductionmentioning

confidence: 99%

Formation of wide binary stars from adjacent cores

Tokovinin¹

2017

Monthly Notices of the Royal Astronomical Society

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“…• inclination of the orbit of Proxima Centauri around alpha Centauri AB (Kervella et al 2017). However, we do not consider these results to be in conflict since, in general, orbital motions in a hierarchical triple system are not expected to be coplanar (e.g., Muñoz & Lai 2015).…”

Section: A Possible Outer Belt At 30 Aumentioning

confidence: 99%

ALMA Discovery of Dust Belts around Proxima Centauri

Anglada

Amado

Ortiz

et al. 2017

ApJL

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Proxima Centauri, the star closest to our Sun, is known to host at least one terrestrial planet candidate in a temperate orbit. Here we report the ALMA detection of the star at 1.3 mm wavelength and the discovery of a belt of dust orbiting around it at distances ranging between 1 and 4 au, approximately. Given the low luminosity of the Proxima Centauri star, we estimate a characteristic temperature of about 40 K for this dust, which might constitute the dust component of a small-scale analog to our solar system Kuiper belt. The estimated total mass, including dust and bodies up to 50 km in size, is of the order of 0.01 Earth masses, which is similar to that of the solar Kuiper belt. Our data also show a hint of warmer dust closer to the star. We also find signs of two additional features that might be associated with the Proxima Centauri system, which, however, still require further observations to be confirmed: an outer extremely cold (about 10 K) belt around the star at about 30 au, whose orbital plane is tilted about 45 degrees with respect to the plane of the sky; and additionally, we marginally detect a compact 1.3 mm emission source at a projected distance of about 1.2 arcsec from the star, whose nature is still unknown.

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“…Doubts concerning the third member companionship of Proxima to α Cen AB have been raised on a number of occasions and it seems clear that, at best, Proxima is only marginally bound under standard Newtonian gravitational conditions [2,3,4], and that under alternative scenarios [5,6] it fits well within the domain of Modified Newtonian Dynamics (MOND). Kervella, Thevenin & Lovis [7] have most recently investigated the orbital dynamics of Proxima, and while they conclude that it is a gravitationally bound object to α Cen AB, their analysis, while claiming a "high degree of confidence" is still not fully convincing -indeed, they find, as with other earlier studies, that the odds of Proxima being a gravitationally bound object to α Cen AB are not much better than 50:50. Indeed, the conclusions drawn by Kervella, Thevenin and Lovis are all in the interpretation of the observational uncertainties, and in the modeling of complicated spectral effects such as extensive line blending, convective blueshift and gravitational redshift.…”

Section: Introductionmentioning

confidence: 83%

“…Indeed, the mass, radius and temperature are known to within an uncertainty of about 5% -its luminosity is a little less well constrained, but measured to an uncertainty of about 10%. Two values of the radius estimate are given in Table 1: the first value (INT) is that derived interferometrically by Demory et al [11], while the second (ML) is that given by Kervella, Thevenin & Lovis [7] based upon the recent 2MASS K s magnitude-radius calibration given by Mann et al [12]. In terms of fitting stellar evolutionary models to the observed data, Proxima is particularly interesting in that the only unknown quantity is its composition, and specifically its metallicity.…”

Section: Model Calculationsmentioning

confidence: 99%

The Composition and Evolutionary Status of Proxima Centauri

Beech¹,

McCowan²,

Peltier³

2017

AJAA

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A suite of stellar evolution models has been used to estimate the mass and metallicity of Proxima Centauri (GJ 551, HIP 70890, V645 Cen). It is found that the observations are best described by an M ≈ 0.12 M star with a heavy element mass fraction in the range 0.004 < Z < 0.01 (or equivalently, a metallicity of -0.5 < [Fe/H] < -0.3). The derived metallicity of Proxima is distinctly at odds with that established for α Cen A and α Cen B. It is argued that both the observational data as well as the evolutionary models for Proxima Centauri are consistent with an age of some 7 to 8 Gyr and that its (presently derived) physical characteristics are inconsistent with an in situ or coevally origin with the α Cen AB binary.

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Proxima’s orbit around α Centauri

Cited by 98 publications

References 57 publications

Formation of wide binary stars from adjacent cores

Formation of wide binary stars from adjacent cores

ALMA Discovery of Dust Belts around Proxima Centauri

The Composition and Evolutionary Status of Proxima Centauri

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