Extrasolar Planets

Dynamical Characterization Of The Multiple Planet System GJ 1148 and Prospects of Habitable Exomoons Around GJ 1148 b

By Keith Cowing
Press Release
February 3, 2020
Filed under
Dynamical Characterization Of The Multiple Planet System GJ 1148 and Prospects of Habitable Exomoons Around GJ 1148 b
Surface temperatures given varying eccentricities and semi-major axes for both a Mars-like (left) and Titan-like (right) moon around GJ 1148 b. The color bars are not identical for each plot. White dots denote the fiducial values; light gray regions indicate surface temperatures in excess of the boiling point of water at 1 atmospheric pressure

Context. GJ 1148 is an M-dwarf star hosting a planetary system composed of two Saturn-mass planets in eccentric orbits with periods of 41.38 and 532.02 days.

Aims. We reanalyze the orbital configuration and dynamics of the GJ 1148 multi-planetary system based on new precise radial velocity (RV) measurements taken with CARMENES.

Methods. We combined new and archival precise Doppler measurements from CARMENES with those available from HIRES for GJ 1148 and modeled these data with a self-consistent dynamical model. We studied the orbital dynamics of the system using the secular theory and direct N-body integrations. The prospects of potentially habitable moons around GJ 1148 b were examined.

Results. The refined dynamical analyses show that the GJ 1148 system is long-term stable in a large phase-space of orbital parameters with an orbital configuration suggesting apsidal alignment, but not in any particular high-order mean-motion resonant commensurability. GJ 1148 b orbits inside the optimistic habitable zone (HZ).

We find only a narrow stability region around the planet where exomoons can exist. However, in this stable region exomoons exhibit quick orbital decay due to tidal interaction with the planet. Conclusions. The GJ 1148 planetary system is a very rare M-dwarf planetary system consisting of a pair of gas giants, the inner of which resides in the HZ. We conclude that habitable exomoons around GJ 1148 b are very unlikely to exist.

The CARMENES search for exoplanets around M dwarfs. Dynamical characterization of the multiple planet system GJ 1148 and prospects of habitable exomoons around GJ 1148 b

T. Trifonov, M. H. Lee, M. Kürster, Th. Henning, E. Grishin, S. Stock, J. Tjoa, J. A. Caballero, K. H. Wong, F. F. Bauer, A. Quirrenbach, M. Zechmeister, I. Ribas, S. Reffert, A. Reiners, P. J. Amado, D. Kossakowski, M. Azzaro, V. J. S. Béjar, M. Cortés-Contreras, S. Dreizler, A. P. Hatzes, S. V. Jeffers, A. Kaminski, M. Lafarga, D. Montes, J. C. Morales, A. Pavlov, C. Rodríguez-López, J. H. M. M. Schmitt, E. Solano, R. Barnes
(Submitted on 3 Feb 2020)

Comments: Accepted for publication in A&A
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2002.00906 [astro-ph.EP] (or arXiv:2002.00906v1 [astro-ph.EP] for this version)
Bibliographic data
From: Trifon Trifonov Ph.D.
[v1] Mon, 3 Feb 2020 17:35:29 UTC (8,385 KB)

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