Geomagnetic Properties of Proxima Centauri b Analogues

The recent discovery of a planet around the closest star, Proxima Centauri, could represent a quantum leap on the testability of models in exoplanet sciences.

Unlike any other discovered exoplanet, models of planetary processes in Proxima b could be contrasted against near future telescopic observations and far future in-situ measurements. In this paper we study the geomagnetic properties of Proxima b analogues, namely, solid planets with masses close but larger than Earth's mass, periods of rotation of several days and habitable surface conditions. Assuming different planetary masses, bulk compositions and periods of rotations, we calculate for each planetary analogue its radius, heat flux, time of inner core formation, dynamo lifetime and minimum dipole magnetic moment.

We find that most (≳70\%) Proxima b analogues develop intrinsic dynamos that last at least 3 Gyr, although only half of them are older than the present age of the host star (4−6 Gyr). Relying in our planetary evolution models, we predict with a 70% confidence level that Proxima b will be an earth-like planet with mass and radius 1.3< Mp<2.3M⊕, Rp=1.4+0.3−0.2R⊕, having today an intrinsic dynamo with a dipole moment Mdip=0.32×2.3÷2.9Mdip,⊕.

Our results rely on the assumptions of flat priors in the input parameters, small orbital eccentricity, negligible tidal heating and earth-like radiogenic mantle elements abundances. The same results obtained for this set of planetary analogues, apply to other earth-like planets having similar observed properties than Proxima b (minimum mass, orbital period and stellar mass).

Jorge I. Zuluaga (SEAP/IF/UdeA), Sebastian Bustamante (H-ITS)
(Submitted on 2 Sep 2016)


Comments: Submitted to ApJL. 8 pages, 4 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1609.00707 [astro-ph.EP] (or arXiv:1609.00707v1 [astro-ph.EP] for this version)
Submission history
From: Jorge Zuluaga [view email]
[v1] Fri, 2 Sep 2016 19:24:54 GMT (2111kb)
http://arxiv.org/abs/1609.00707

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