An international team of researchers led by the University of Cologne in Germany studied how solar flares erupted by the TRAPPIST-1 star could affect the interior heating of its exoplanets.
The study could help us understand how solar flares affect planetary evolution. The TRAPPIST-1 system is an exoplanetary system located approximately 39 light-years from Earth with at least seven potentially rocky planets in the vicinity of a star that has less mass than our own sun. Our own solar system is larger than the TRAPPIST-1 system because the parent star is smaller. How can this study help us better understand the habitability of planets?
The entire surface of the planet has been shaped by geological activity if we take Earth as our starting point.
The Earth has radioactive elements in its interior that allow geological processes to persist beyond 4.5 years. The question arises if radioactive elements are required to drive geological processes that may allow life to evolve. The hypothesis that geological activity is rare is supported by the fact that some processes can generate heat inside a planet.
TRAPPIST-1 is an M-type star, which is smaller than the sun and emits less solar radiation.
"M stars are the most common star type in our stellar neighborhood, and TRAPPIST-1 has received a lot of attention since it was discovered to be circled by seven Earth-sized planets," said Dr.
For the planets closest to the star, the interior heating from flares is significant and can drive geological activity. The process is long-lived and can persist over geological timescales, allowing the surface environment to evolve towards a series of states. The influence of stellar flares on habitability has mostly been considered to be destructive. Flares may actually promote the establishment of a near- surface environment according to our results.
Ohmic loss is a loss of electric energy due to conversion into heat when a current flows through a resistance It is what scientists used to calculate the amount of heat a planet loses.
The study found that the cooling of the TRAPPIST-1 planets would lead to thicker atmospheres. The heating results can be improved by the presence of a planetary magnetic field.
One of the planets in the TRAPPIST-1 system has a low probability of having a hydrogen atmosphere like the gas planets in our own solar system. It's possible that one of TRAPPIST-1's planets could have a similar atmosphere to Earth, Mars, and Venus. What follow up research is planned for this study?
There are two obvious ways to go about pursuing it. Our stellar neighborhood is dominated by M stars and so observational campaigns can assess the flaring nature of many more M stars. Our understanding of the planetary interiors will be improved by enhanced characterization of the TRAPPIST planetary system. We will be able to refine our model in regards to whether the planets have an iron core or a large silicate mantle.
The Heisenberg Junior Research Group Leader at the University of Cologne is the lead author of the study. The goal is to model atmosphere formation and erosion with our model.
Alexander Grayver and his co-authors wrote about interior heating of rocky exoplanets from stellar flares with application to TRAPPIST-1 in the Astrophysical Journal Letters. There is a document titled "10847/2041-8213/aca287".
Journal information: Astrophysical Journal Letters
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