Detection and Characterization of the Temperate Super-Earth Ross 318 b

Ross 318 is an M3.5V red dwarf exhibiting significant magnetic activity and a stellar rotation period of ∼ 51.5 d.

In this work we present a systematic re-analysis of radial velocities (RV) from CARMENES and decade-long HIRES observations, integrated with TESS space-based photometry.

We identify a terrestrial-mass planet, Ross 318 b, with an orbital period P = (39.6299 ± 0.29) d and a minimum mass M sin i = (6.21 ± 0.62)M_⊕. The dynamical nature of the signal is confirmed by its temporal coherence over a 15-year baseline and its achromaticity between visible and near-infrared channels.

TESS photometry from Sectors 18, 19, 24, and 25 (218.6 d total baseline, 66 983 cadences) reveals no transit at P = 39.63 d (FAP > 10%, BLS). An injection-and-recovery test demonstrates that a 2200 ppm transit signal corresponding to a 1.74R_⊕ body would have been detected with Signal-to-PinkNoise Ratio SPNR > 12, ruling out a transiting geometry with high confidence.

The orbital inclination is constrained to i < 88.5^◦ . With an incident stellar flux S_ef f ≈ 0.58 S_⊕ and bolometric luminosity L_∗ = (0.01478±0.00122)L_⊙, Ross 318 b falls within the Conservative Habitable Zone, making it one of the most interesting temperate Super-Earths orbiting an M dwarf.

G.Conzo, M.Moriconi, S.A.Corrêa Jr

Comments: 17 pages, 4 figures, 2 tables. Submitted at OEJV
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2605.11123 [astro-ph.EP] (or arXiv:2605.11123v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2605.11123
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Submission history
From: Giuseppe Conzo Dr.
[v1] Mon, 11 May 2026 18:31:54 UTC (1,028 KB)
https://arxiv.org/abs/2605.11123

Astrobiology