Exomoons — natural satellites of planets outside our Solar System — could offer another clue about the pool of alien worlds that may be home to life, according to new research by Dr. Phil Sutton, an astrophysicist and lecturer in the School of Maths and Physics at the University of Lincoln.
Artist’s impression of a potentially habitable exomoon orbiting a giant planet. Image credit: Sci-News.com.
Only a small proportion of exoplanets are likely to be able to sustain life, existing in what is known as the habitable zone.
But some planets, especially large gas giants, may harbor moons which contain liquid water.
“These moons can be internally heated by the gravitational pull of the planet they orbit, which can lead to them having liquid water well outside the normal narrow habitable zone for planets that we are currently trying to find Earth-like planets in,” Dr. Sutton said.
“I believe that if we can find them, moons offer a more promising avenue to finding extraterrestrial life.”
Dr. Sutton looked at the possibility of exomoons orbiting J1407b, the first large gas giant believed to have en enormous ring system outside of the Solar System.
The rings of J1407b are shown eclipsing the young Sun-like star J1407. Image credit: Ron Miller.
J1407b circles a 16-million-year-old Sun-like star approximately 434 light-years away from Earth.
The planet’s mass is most likely in the range of about 10 to 40 Jupiter masses.
Dr. Sutton ran computer simulations to model the rings around J1407b, which are 200 times larger than those around Saturn.
Gravitational forces between all particles were calculated and used to update the positions, velocities and accelerations in the computer models of J1407b and its ring system.
The researcher then added a moon that orbited at various ratios outside of the rings to test whether this caused gaps to form where expected over 100 orbital periods.
“The findings revealed that while the orbiting moon did have an effect on the scattering of particles along the ring edge, the expected gaps in the ring structure were unlikely to be caused by the gravitational forces of a currently unseen moon orbiting outside J1407b’s rings,” Dr. Sutton said.
His paper was published in the Monthly Notices of the Royal Astronomical Society.
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Phil J. Sutton. 2019. Mean motion resonances with nearby moons: an unlikely origin for the gaps observed in the ring around the exoplanet J1407b. MNRAS 486 (2): 1681-1689; doi: 10.1093/mnras/stz563
