2024-05-15, 06:48 PM
Here's the promised update for the close approach of the kilometer-sized NEO (415029) 2011 UL21. The orbit is well defined and the parameters haven't changed. CNEOS predicts that the NEO will make a close approach on 2024-Jun-27 20:16±<00:01 UT at a distance of 0.04439 AU moving with V Relative=25.88 km/sec, H=15.9 magnitude, diameter 1.7 km - 3.9 km and 'Rarity'=3. This object has a 12872 day observation arc, the Condition Code=0 and the Earth MOID=0.0171455 AU The solution date was 2024-Apr-03 05:49:27 PDT. This MP was discovered at Kitt Peak on 2006-05-27 by Spacewatch. It's not surprising that the close approach parameters haven't changed since April 30, since CNEOS performed the close approach calculations on Apr 3.
Using MPC's elements for the epoch 2024 May 15 0000 UT, ST4v predicts that this NEO will reach a peak brightness of 11.7 magnitude on the evening of June 28 at a distance of 0.05 AU traveling through Virgo at ~40"/minute. Close approach is predicted (to the nearest hour) on 2024 Jun 27 at 1600 EDT when the MP will be 11.9 magnitude traveling through Hydra at ~48"/minute in daylight as seen from Columbus, Ohio. Africa looks like the best place to observe the close approach, but this NEO is predicted to be brighter than 15.5 magnitude from June 21 to July 17, so there's plenty of opportunity to observe this large rock as it passes by. It might be worth adding to the Current Bright & Interesting Minor Planets OL for June and July before it fades from view. It will start out best from the southern hemisphere, but steadily move north heading toward Hercules so everyone will have a chance to view this MP.
Here's the Interactive Atlas chart for this NEO as seen from Columbus, Ohio:
Here's the Object Info dialog for this NEO:
As a 'Rarity'=3 event, a close approach of a NEO this large and close is very rare. Typically there's only 1 or 2 per year. On 2089 Jun 25 (415029) 2011 UL21 will be 0.01782 AU distant. I wonder what the 'Rarity' will be for that!
Good hunting,
Phil S.
Using MPC's elements for the epoch 2024 May 15 0000 UT, ST4v predicts that this NEO will reach a peak brightness of 11.7 magnitude on the evening of June 28 at a distance of 0.05 AU traveling through Virgo at ~40"/minute. Close approach is predicted (to the nearest hour) on 2024 Jun 27 at 1600 EDT when the MP will be 11.9 magnitude traveling through Hydra at ~48"/minute in daylight as seen from Columbus, Ohio. Africa looks like the best place to observe the close approach, but this NEO is predicted to be brighter than 15.5 magnitude from June 21 to July 17, so there's plenty of opportunity to observe this large rock as it passes by. It might be worth adding to the Current Bright & Interesting Minor Planets OL for June and July before it fades from view. It will start out best from the southern hemisphere, but steadily move north heading toward Hercules so everyone will have a chance to view this MP.
Here's the Interactive Atlas chart for this NEO as seen from Columbus, Ohio:
Here's the Object Info dialog for this NEO:
As a 'Rarity'=3 event, a close approach of a NEO this large and close is very rare. Typically there's only 1 or 2 per year. On 2089 Jun 25 (415029) 2011 UL21 will be 0.01782 AU distant. I wonder what the 'Rarity' will be for that!
Good hunting,
Phil S.