The quest to unveil the mysteries of life beyond Earth propels astrophysicists towards discovering habitable planets amidst the expanding collection of over 5000 worlds found beyond our solar system. A group of Indian scientists has embarked on a journey to decode a pivotal factor in this pursuit: the role of magnetic fields of stars and their accompanying planets in determining habitability. Their groundbreaking study, documented in the Astrophysical Journal, sheds light on the intricate interplay between stellar and planetary magnetism, unravelling its profound influence on the critical atmospheric erosion necessary for life to thrive.
GUARDIAN OF LIFE ON EARTH
The guardian of life on Earth, the magnetic field or magnetosphere, acts as an imperceptible shield thwarting the barrage of high-energy particles and plasma discharged by the Sun. This shield prevents our precious atmosphere from being whisked away by the solar winds, thus enabling life’s existence. Alas, not all celestial bodies share Earth’s fortune. The likes of Mars, bereft of its magnetic field, undergo the gradual erosion of their atmospheres at the hands of relentless solar winds.
Drawing expertise from the Centre of Excellence in Space Sciences India and the Department of Physical Sciences at the Indian Institute of Science Education and Research Kolkata, this team of researchers harnessed computational modelling to unravel the impact of diverse combinations of planetary and stellar magnetic field strengths. Their inquiry unveiled how these factors influence a planet’s magnetic arrangement and atmospheric attrition. Surprisingly, their findings debunked conventional assumptions by demonstrating that, under specific conditions, an intrinsic magnetic field could amplify atmospheric loss.
Elucidating this enigma, Professor Dibyendu Nandi, a key figure in the study, shared, “The ability of a planet to foster life hinges on a multitude of puzzle pieces falling into place, encompassing elements as unexpected as the strength of the concealed magnetic field cocooning the planet and the magnetic potency of its parent star—the Sun, in our case.”
The simulations conducted by the team unveiled an enthralling phenomenon: when a planet’s magnetic force pales in comparison to that of its stellar counterpart, the planet’s magnetosphere unfurls wing-like structures coined “Alfven wings.” These wings, named after the pioneering contributions of Swedish Nobel laureate Hannes Alfvwn to magneto hydrodynamics, embody a striking transformation in the cosmic ballet of magnetic fields.
“In this study, we decode the intricate interplay of cosmic magnetic fields that underlie the loss of a planet’s atmosphere and its hospitability. We have devised a mathematical equation that elegantly encapsulates this intricate process,” Professor Nandi further expounded.
These revelations spotlight that our understanding of the intricate nexus between magnetism, star-planet dynamics, atmospheric erosion, and planetary habitability has barely scratched the surface. As humanity’s gaze extends towards an ever-growing exoplanet inventory, studies of this nature are poised to be pivotal in appraising the potential of these distant worlds to foster life.