Oral comunication
J. Ferreira, P. Machado
Abstract
Asteroids are involved in understanding several key issues in Solar System science and the space environment of our planet, such as the conditions of the Solar System during its formation, the delivery of water and organic molecules to Earth, the potential danger of Near Earth Asteroids (NEA) and their role in affecting Earth’s climate. Stellar occultation events are a unique opportunity to obtain from the ground very accurate asteroid astrometry, close to the performance of Gaia, and shapes/sizes. When an asteroid hides the light of a star, the uncertainty of its instantaneous position can be similar to that of the target star. By exploiting the accuracy of Gaia DR2 on both asteroids and stars, stellar occultation prediction and exploitation becomes an effective method to systematically collect asteroid astrometry. The improvement of predictions through Gaia DR2 is proven via statistics of real predictions and comparison between stellar occultation predictions with Gaia DR2 for asteroids and other, such as Astorb and MPCORB, to verify which fit better to observed chords of past occultations. At the same time, asteroid occultations can offer the possibility to confirm or discover double stars, in a range of small angular separations very complementary to the resolution accessible to Gaia itself. We will present statistics and simulations showing the improvement expected in the prediction of asteroid occultations thanks to Gaia astrometry, in particular regarding the smaller uncertainties on the proper motion of target stars.Through a bayesian approach, we determine in the parameter space (duration ; flux drop ; star brightness) the domain of detectable events from a single site. Our study prepares the exploitation of the 0.5-m robotic telescope at "Plateau de Calern" (Southern France) Universcity, for which we determine the range of asteroid size and star brightness that we expect to reach. This facility will start operations in a few months.After this work simulating the expected performance of Universcity with the available equipment, the plan is to apply these limitations to predicted events and maximize the efficiency of the telescope’s use.
XXIX Encontro Nacional de Estudantes de Astronomia
Lisboa, Portugal
2019 September
