Featured Image: Grasping at Tilted Planets’ Atmospheres


How does tilting a planet affect its ability to hold on to its atmosphere in the face of intense stellar radiation? The above images are from a series of numerical simulations run by a team of scientists led by Chuanfei Dong (Princeton University), which explore the role of magnetic obliquity — the tilt of the planet’s magnetic field — in regulating the loss of ions from an exoplanet’s atmosphere. In particular, Dong and collaborators modeled Earth-like planets in the habitable zones of two different host stars: a Sun-like G dwarf (top row) and a TRAPPIST-1-like M dwarf (bottom row). The simulation frames above show the ion loss from these two planets with four different tilts: 0°, 45°, 90°, and 135° (columns from left to right). While obliquity doesn’t much affect mass loss for a planet around a Sun-like star, the planet around the M-dwarf loses twice as much mass when its obliquity is oriented at 90° than it does when it’s aligned at 0° — which could matter for such a planet’s potential habitability! For more information on the authors’ conclusions, check out the article below.


“Role of Planetary Obliquity in Regulating Atmospheric Escape: G-dwarf versus M-dwarf Earth-like Exoplanets,” Chuanfei Dong et al 2019 ApJL 882 L16. doi:10.3847/2041-8213/ab372c