Interior And Climate Modeling of the Venus Zone Planet TOI-2285 b
As the discovery of exoplanets progresses at a rapid pace, the large number of known planets provides a pathway to assess the stellar and planetary properties that govern the climate evolution of terrestrial planets.
Of particular interest are those planetary cases that straddle the radius boundary of being terrestrial or gaseous in nature, such as super-Earth and sub-Neptune exoplanets, respectively.
The known exoplanet, TOI-2285 b, is one such case, since it lies at the radius boundary of super-Earth and sub-Neptune (Rp=1.74 R⊕), and receives a relatively high instellation flux since its orbit exists within both the Habitable Zone (HZ) and Venus Zone (VZ). Here, we present an analysis of the planetary interior and climate to determine possible evolutionary pathways for the planet.
We provide volatile inventory estimates in terms of the planet’s bulk density and interior composition. We performed climate simulations using ROCKE-3D that provide a suite of possible temperate scenarios for the planet for a range of topographical and initial surface water assumptions.
Using the outputs of the climate simulations, we modeled JWST transmission and emission spectroscopy for each scenario. Our results demonstrate that there are temperate scenarios consistent with the known planetary properties, despite the planet’s estimated steam atmosphere, and its location relative to the VZ.
Histogram of number of oceans of H2O as steam in a planet’s atmosphere. The distribution is bimodal, indicating two distinct populations. 29% of data points suggest TOI-2285 b is relatively dry (i.e. water-poor), with < 0.1% Earth oceans of water vapor in the atmosphere. A portion of the remaining 71% correspond to a relatively water-rich atmosphere. For the water-rich population, the mean number of oceans is 5260 Earth oceans. The difference in variance between these populations further supports the distinction between the water-poor and water-rich populations.– astro-ph.EP
The ROCKE-3D GCM simulation outputs. Six climate scenarios were generated using Venus, aquaplanet and Earth topographies with varying amounts of surface water. Here, we have plotted the surface temperature, and the surface water fraction. The semi-opaque white hatched regions in the bottom row indicate regions with at least partial ice coverage. — astro-ph.EP
Emma L. Miles, Colby Ostberg, Stephen R. Kane, Ondrea Clarkson, Cayman T. Unterborn, Tara Fetherolf, Michael J. Way, Sadie G. Welter
Comments: 17 pages, 8 figures, 3 tables, accepted for publication in the Astronomical Journal
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2505.10647 [astro-ph.EP] (or arXiv:2505.10647v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2505.10647
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Submission history
From: Emma Miles
[v1] Thu, 15 May 2025 18:39:40 UTC (2,220 KB)
https://arxiv.org/abs/2505.10647
Astrobiology,
