University of Arizona | 2019 Apr 16
Two new studies by UA space scientists may bring into question the habitability of TRAPPIST-1 exoplanets.
Since its discovery in 2016, planetary scientists have been excited about TRAPPIST-1, a system where seven Earth-sized rocky planets orbit a cool star. Three of the planets are in the habitable zone, the region of space where liquid water can flow on the planets’ surfaces. But two new studies by scientists in the University of Arizona’s Lunar and Planetary Laboratory may lead astronomers to redefine the habitable zone for TRAPPIST-1.
- The relative size of the TRAPPIST-1 planets and their orbits. The entire TRAPPIST-1 system could fit within the orbit of Mercury, with plenty of room to spare. The red band indicates the orbits where space is too hot for liquid water to pool, the blue band indicates where space is too cold for water to be liquid, and the green band indicates the habitable zone. Image credit: NASA/JPL-Caltech
The three planets in the habitable zone are likely facing a formidable opponent to life: high-energy particles spewed from the star. For the first time, Federico Fraschetti and a team of scientists from the Center for Astrophysics | Harvard & Smithsonian have calculated how hard these particles are hitting the planets.
Meanwhile, Hamish Hay, a graduate student in the Lunar and Planatary Laboratory, has found that the gravitational tug-of-war the TRAPPIST-1 planets are playing with one another is raising tides on their surfaces, possibly driving volcanic activity or warming ice-insulated oceans on planets that are otherwise too cold to support life. ...
Stellar Energetic Particles in the Magnetically Turbulent Habitable Zones
of TRAPPIST-1-like Planetary Systems ~ F. Fraschetti et al
- Astrophysical Journal 874(1):21 (2019 Mar 20) DOI: 10.3847/1538-4357/ab05e4
arXiv.org > astro-ph > arXiv:1902.03732 > 11 Feb 2019
Tides Between the TRAPPIST-1 Planets ~ Hamish C.F.C. Hay, Isamu Matsuyama