Recently, the research members of division for planetary sciences and deep space exploration present a new result that the Damocloids objects may be come from two possible regions: the scattered disk, or a part of Oort cloud.

On March 10, 2010, Professor Zhao Haibin and his colleges discovered a new asteroid moving along a very eccentric orbit, designated as 2010 EJ104. They observed this rapidly moving object using 1.04/1.20 m Schmidt Telescope (Near Earth Object Survey Telescope) at Xuyi station of Purple Mountain Observatory. The orbital elements are then determined by utilizing follow-up measurements from several observatories – the semi-major axis a = 21.58 AU, eccentricity e = 0.90.

According to the Tisserand Parameter for 2010 EJ104, it is estimated to be a new member of Damocloids. Then a natural question may be raised – where does the Damocloids come from and is there a source or region that may replenish these comparable objects?

They studied the origin of the Damocloids from the point of backward simulations and found that the Damocloids may come from two regions, the scattered disk which will be perturbed by the major planets or the sun, the Oort cloud which will be perturbed into the transient disk locating from 700 AU to 1000 AU. If the Damocloids come from inner Oort cloud, the bodies might be stirred by perturbation of the passing stars or the tidal effect by the Galactic disk, then continuously moved inward to the intermediate region, and finally ejected into the inner solar system. Based on the statistical results, about 2/3 mainly come from the inner Oort cloud and others come from the scattered disk.

The dynamical evolution for the Damocloids may uncover a connection passage from the Main Belt, the Kuiper Belt and the scattered disk beyond. The study has been accepted by Research in Astronomy and Astrophysics.