The following table contains the noteworthy notes about our asteroid impact monitoring system.
| 2021-Mar-26 | The radar observations made in March 2021 of (99942) Apophis have allowed a substantially improved Yarkovsky effect estimate. The current value of the A2 Yarkovsky parameter is (-2.90 +/- 0.25) 10-14 au/d2. As a consequence, all the virtual impactors have been eliminated and this historical asteroid has been removed from the Risk List. |
| 2021-Jan-20 | With the apparition of (99942) Apophis of late 2020 - early 2021, new optical observations were available. NEODyS updated the orbit with the determinaton of the A2 Yarkovsky drift to be (-2.84 +/- 0.38) 10-14 au/d2. NEODyS rerun the Impact Monitoring and updated the Impact Risk Table. Due to the already high precision of the orbit determination, NEODyS will update occasionally during this apparition, when the optical and radar detections will provide a significant contribution. |
| 2020-Nov-20 |
New observations of asteroid (410777) 2009 FD have been
submitted on 2020-Nov-16
(MPEC
2020-W27). The updated orbit and the improved Yarkosvky
drift estimate ruled out the remaining virtual impactor in
2190. As a consequence, asteroid (410777) 2009 FD have been
removed from the Risk List. |
| 2019-Oct-29 |
We switched to the weighting scheme for asteroid astrometry
presented in
Veres et al. (2017). We
recomputed all the orbits of NEODyS using this new error model
and updated the Risk List with the resulting hazard
assessment. Note that such a change might affect the hazard
assesment results. |
| 2019-Jul-16 |
We have updated the impactor table of asteroid (410777) 2009
FD. The astrometry collected during the 2019 apparition
improved the constraint on the secular semimajor axis drift
caused by the Yarkovsky effect and in turn on the trajectory
of the asteroid. We adopted a generalisation of the Line Of
Variations method in a 7-dimensional space. As a result, the
main impact possibility in 2185 is ruled out and the only
remaining one is in 2190, but with a very low probability. For
further details refer
to Del Vigna et al. (2019). |
| 2016-Oct-31 |
We updated the Risk List after the switch to a different
method to sample the Line Of Variations. This new method is
described in detail in the
paper Del Vigna et al. (2019) and it is
uniform in the probability of each sampling interval rather
than in the length of each interval, which was the one in use
previously. Note that such a change might affect the hazard
assesment results. |