Centrum Astronomii
Uniwersytet Mikołaja Kopernika

Fast and bright. Detection and physical characterisation of the Chelyabinsk class Near Earth Objects

dr hab. Tomasz Kwiatkowski (OA UAM)

Źródło zdjęcia: https://www.fizyka.amu.edu.pl/dla-szko/dla-szko/wykady-otwarte
Within the population of the Near Earth Objects (which encompasses both asteroids and comets that can come close to the Earth) there exists a group of the smallest, observationally accessible bodies, which remain a poorly studied, but important part of the NEOs. These very small (D < 150 m) NEOs far out-number their larger counterparts, often pass the Earth at distances smaller than that of the Moon, and thus pose the most immediate impact hazard (as shown, for example, by the explosion of the D=17m NEO over the city of Chelyabinsk in 2013). They are also easily accessible for the in-situ exploration by space probes. The well known Pan-STARRS and LSST surveys are optimized for finding larger NEOs at greater distances and are examples of the "deep and narrow" strategy. However, there is also a "shallow and wide" approach which is optimized for finding smaller NEOs at closer distances. The ATLAS telescopes funded by NASA and the Fly-Eye telescopes build by ESA are two such systems which are currently coming into operation. Both surveys should be supplemented by efficient follow-up telescopes capable of securing orbits of newly discovered NEOs so that they are not lost due to inaccurate ephemerides. At the time of writing this there is a discussion about Poland's role in building such follow-up system under a contract from ESA. Its design shall be presented during the talk. Apart from detection and orbit determination, there is also a need for physical characterisation of the smallest NEOs. Currently the most productive in this area is the MANOS project based on photometric, Vis and IR spectroscopic observations providing information on sizes, rotation periods and mineralogical composition of NEOs. A supplementary approach would focus on selected objects with the goal of deriving their more detailed models including spin axis and a 3D shape. An example of such a model, obtained during the international observing campaign for 2015 AZ43, shall be presented.

09.01.2017 - 11:15
Sala seminaryjna KRA