Description du projet
Au-delà de Neptune: la lumière d’une étoile bloquée révèle des formes, une atmosphère et des anneaux
Neptune, la planète la plus éloignée de notre système solaire, a pris forme il y a 4,5 milliards d’années. Elle s’est probablement formée plus près du Soleil et s’est déplacée vers le système solaire externe il y a environ 4 milliards d’années. Neptune et les objets de la ceinture de Kuiper (planètes mineures, dont Pluton, en orbite autour du Soleil au-delà de Neptune) sont porteurs d’informations essentielles sur la formation et l’évolution de notre système solaire. Le projet LUCKY STAR, financé par le CER, exploitera ses méthodes et instruments de pointe pour analyser les occultations stellaires (obstructions de la lumière d’une étoile par un objet situé entre l’étoile et l’observateur) afin d’étudier les objets de la ceinture de Kuiper et de mieux comprendre les anneaux autour des petits corps, l’atmosphère de Pluton et les objets de la ceinture de Kuiper d’une taille allant de moins d’un kilomètre à un millier de kilomètres.
Objectif
The solar system beyond Neptune’s contains largely unaltered material from the primordial circum-solar disk. It also kept the memory of the early planetary migrations, and thus contains essential information on the origin and evolution of our planetary system.
Here I propose to study the Trans-Neptunian Objects (TNOs) using the stellar occultation technique. It consists in observing the passage of remote TNOs in front of those “Lucky Stars”, that reveal shapes, atmosphere and rings of bodies from sub-km to thousand-km in size. Very few teams in the world master this method. The European-led network that I coordinate is now leader in predictions, instrumentation, observations and analysis related to stellar occultations, with innovative approaches and unprecedented results.
In the last decade, our group led the field by discovering rings around the asteroid-like object Chariklo, detecting sub-km TNOs and drastic variations of Pluto’s atmospheric pressure. Based on those noteworthy discoveries and unique skills of ours, I will coordinate the following work packages:
(1) Rings around small bodies - Understand the newly found Chariklo’s rings, tackle the theory of rings’ origins and evolutions around small bodies, discover new ring systems around other bodies.
(2) Very small, sub-km TNOs and Oort Cloud objects - Constrain the collisional history of our early outer solar system, and possibly detect Oort Cloud objects.
(3) Pluto’s atmosphere – Explore Pluto’s atmosphere and its atypical seasonal cycle, search for atmospheres around other TNOs.
(4) Explore specific, large TNOs – Provide their sizes, shapes, albedos and densities.
These programs are timely in view of NASA/New Horizons Pluto flyby in July 2015, and the ESA/GAIA mission expected to provide a greatly improved astrometric catalog release in 2016.
Most of the budget will be dedicated to human power to conduct observations and their analysis, plus the associated travel and telescope time expenses.
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ERC-ADG - Advanced GrantInstitution d’accueil
75006 Paris
France