2001 WN5

The following message was put on the New Announcements list on November 28, 2001:

According to the NEODyS Risk Page, 2001 WN5, a NEA with H = 18.0, currently flagged as Urgent in the Priority List, shows many Virtual Impactor solutions (all of them with very low impact probability). The great part of these impact possibilities is due to the high uncertainty in the object's MOID, and probably they will disappear as soon as new observations will be available. This is the reason why we decided to wait for a few days after the recognition of the collision solutions before opening a new campaign; however, due to the lack of astrometric data after the discovery announcement, on MPEC 2001-W51, we call the attention of the observers on this object.

Although 2001 WN5 will be between magnitude 19 and 20 for the whole month of December, observations are needed as soon as possible since its sky uncertainty is growing very rapidly. The moon should not pose problems to observations in about 2-3 days, but well equipped facilities should be able to detect it even tonight.

Thank you very much for your attention,

November 28, 2001

The following note was added on December 20, 2001:

Thanks to the observations reported until December 17, 2001 by several observers all the collision solutions were removed. We will close this campaign (reporting all the details) as soon as further observations of 2001 WN5 will secure its orbit for a future recovery.

December 20, 2001

The collision solutions were removed thanks to astrometric observations obtained from many stations around the world, both amateur and professional. Here are the details of the teams that partecipated since the start of this campaign: observation were conducted at Jornada Observatory, NM, USA, on December 2, 10, 17, at Siding Spring Observatory, Australia, on Dec. 4, at Powell Observatory, KS, USA, on Dec. 6, at the Dominion Observatory, Canada, on Dec. 7, at Sormano, Italy, on Dec. 10, at San Marcello Pistoiese, Italy, on Dec. 12, at Mallorca, Spain, on Dec. 13, at Ametlla de Mar, Spain, on Dec. 14, at Loomberah, Australia on Dec. 16, and by the Spacewatch team at Kitt Peak Observatory, AZ, USA, on Dec. 17.

Further observations made by D. Dixon at Jornada Observatory, NM, USA on December 27 and by Tim Spahr at Mount Hopkins Observatory, AZ, USA, on January 9, contributed to refine its orbit and provide good prospects for recovery in February/March 2003 at magnitude 21.0 V.

The Spaceguard Central Node, January 22, 2002, Rome, Italy