The Beta Pictoris system has been the cosmic corner in which astrophysicists have found a wide spectrum of comets.
The Institut d’Astrophysique de Paris (CNRS) has detected the presence of up to 30 comets , with nuclei that vary in size, circulating through the planetary system in formation of the young star Beta Pictoris, located 63 light years away from us.
A memorable planetary system
For the last thirty years, the star β Pictoris has fascinated astronomers because it allows them to observe a planetary system in the process of formation. To our knowledge, it consists of at least two young planets and also contains comets (which were the first observed around a star other than the Sun).
Now, an international team of scientists led by Alain Lecavelier des Etangs, a CNRS researcher at the Institut d’Astrophysique de Pariha, has discovered 30 of these exocomets and has determined the size of their nuclei thanks to observations made over 156 days using the NASA’s Transiting Exoplanet Survey Satellite (TESS ) mission.
The star Beta Pictoris, which was discovered almost 40 years ago, is surrounded by a debris disk made of gas and dust, which has already given birth to two young planets that orbit around it. It is an emerging system compared to ours. Our solar system is 4.5 billion years old, while Beta Pictoris is only 20 million years old , which, astronomically speaking, is quite young.
And how are their nuclei?
In addition to discovering 30 exocomets, the researchers were also able to determine the size of cometary nuclei , the icy “dirty snowball” that makes up the heart of a comet. Exocomet nuclei range from 3 to 14 kilometers in diameter, similar to comets in our own solar system. This pattern suggests that the processes that formed the exocomets around Beta Pictoris are the same as those that formed the comets in our solar system.
This is the first time astronomers have measured the size distribution of comets in another planetary system.
Thus, although Beta Pictoris is not the first star around which exocomets have been discovered, it is the first star for which it has been possible to measure the size distribution of comets.
Reference: Alain Lecavelier des Etangs, Lucie Cros, Guillaume Hébrard, Eder Martioli, Marc Duquesnoy, Matthew A. Kenworthy, Flavien Kiefer, Sylvestre Lacour, Anne-Marie Lagrange, Nadège Meunier, Alfred Vidal-Madjar. Exocomets size distribution in the β Pictoris planetary system. Scientific Reports, 2022; 12 (1) DOI: 10.1038/s41598-022-09021-2
