BepiColombo mission detects escaping gases in Venus's magnetosphere

BepiColombo mission detects escaping gases in Venus's magnetosphere
by Erica Marchand
Paris, France (SPX) Apr 12, 2024

The ESA/JAXA BepiColombo mission has provided new insights into the atmospheric dynamics of Venus, showing how carbon and oxygen escape from the upper atmosphere. During its journey, the spacecraft explored a previously unknown area of Venus's magnetic environment, revealing that these gases are accelerated beyond the planet's gravitational hold. This discovery was detailed in a recent publication in Nature Astronomy.

Lina Hadid, a CNRS researcher at the Plasma Physics Laboratory (LPP) and lead author of the study, noted, "This is the first observation of positively charged carbon ions escaping Venus's atmosphere. These heavy ions are typically slow, which puzzles us as to the mechanisms driving their escape, potentially involving electrostatic forces or centrifugal processes."

Venus lacks an intrinsic magnetic field, unlike Earth. However, interactions between the solar wind and Venus's ionized upper atmosphere generate a weak induced magnetosphere, shaped like a comet's tail. The magnetosheath, a surrounding area where the solar wind is decelerated and heated, plays a crucial role in these interactions.

On August 10, 2021, BepiColombo executed a flyby maneuver at Venus to adjust its trajectory towards Mercury. During this maneuver, it collected significant data on the magnetosheath's chemistry and physics, offering insights into how Venus's atmosphere has evolved, particularly in the loss of water. Previous missions have examined Venus's atmospheric loss but left gaps that BepiColombo now fills.

The data, gathered using the Mass Spectrum Analyzer (MSA) and the Mercury Ion Analyzer (MIA) aboard Mio, the Mercury Magnetospheric Orbiter led by JAXA, underscore the complexities of atmospheric escape mechanisms. Dominique Delcourt, a researcher at LPP and principal investigator of the MSA instrument, emphasized the importance of understanding these mechanisms to grasp how Venus lost its water.

Europlanet's SPIDER space weather tools were instrumental in tracking particle movements through Venus's magnetosheath, highlighting the benefits of planetary flybys for inaccessible regions exploration, according to Nicolas Andre from the Institut de Recherche en Astrophysique et Planetologie (IRAP).

Over the next decade, a fleet of missions including ESA's Envision, NASA's VERITAS and DAVINCI, and India's Shukrayaan will further dissect the Venusian environment. "These upcoming missions are vital for piecing together the historical puzzle of Venus's atmosphere," added Moa Persson from the Swedish Institute of Space Physics.

Research Report:BepiColombo observations of oxygen and carbon ions in the flank of Venus induced magnetosphere