December Hot Month for Near Earth Passes

[bigmasterdrago]

I was looking into next month and ran by a few near Earth approaches. I ran all of these using precision osculating elements provided by Horizons. These are all near the edge of my 13" and local conditions but are added to my calendar. Since they are close at near pass, I recommend plotting from your locations.

2015 RN35 on December 15, 08:10UT, makes a 1.78LD pass thru Fornax and Eridanus moving NE at just over 1.5'/min around mag 13.6. This big rock rock climbs into a much more favorable location for SE Texas as it reaches 42° and mag 13.3 (improved phase angle) in the predawn hours of Dec 16th. The 50% illuminated Moon is 90° away.

2018 YK2 on December 22, 05:34UT, this big rock makes a 2LD pass thru Lacerta moving NNE at 3.7'/min at mag 14.4. For me, very low in the NW. However, the next 24 hours offers a much higher vantage point (54° & due north - Camelopardalis) and phase angle improvement. Even though the distance doubles to 4LD and proper motion drops to 1'/min, the magnitude slightly brightens to 14.2.

2010 XC15 on December 27, 18:14UT, this very large rock makes a 2LD pass out of Bootes into Corona Borealis moving east at 2.6'/min near magnitude 14.0 when it's poorly placed for SE Texas. If I attempt observations 6 hours earlier, just prior to the onset of morning twilight, the big rock from space should be 63° up moving 2.4'/min in the east and ~mag 13.5. And still only slightly over 2LD away. The Moon is not a factor.

[PMSchu]

Thanks, BMD.  2015 RN35 has a 'Rarity'=2 close approach according to the CNEOS website and 2010 XC10 has a 'Rarity'=3. 2018 YK2 isn't listed on the CNEOS website. Looking at the particulars for that NEO, JPL's Small Body Database Lookup website indicates a close approach on 2022-Dec-26 01:21 ± 4_13:23 UT at 0.04038 AU. The possible minimum separation is 0.00519 AU and the maximum separation is 0.08807 AU. That's using elements for 2022 Aug 9 00:00 UT.

It's probably worth keeping an eye on 2018 YK2 to see if the MPC gets better elements before the close approach occurs. 

There's a recent discovery, 2022 UD9 that has a 'Rarity'=2 that makes a close approach on 2022-Dec-22 11:31 ±  00:16 UT at 0.01189 AU. I was waiting for the uncertainty to improve before posting about that one.

Phil S.

[PMSchu]

As of today, CNEOS still hasn't improved the uncertainty of the time of close approach of 2018 YK2. It's unchanged from what was posted on November 19.

They have improved the accuracy for 2022 UD9 considerably, but it's a southern hemisphere object that's predicted to reach peak brightness of 15.6 magnitude on December 19 in Horologium moving 31"/min. 'Rarity'=2.

I can upload a chart for 2022 UD9 if anyone's interested.

Phil S.

[bigmasterdrago]

<snip>
2010 XC15 on December 27, 18:14UT, this very large rock makes a 2LD pass out of Bootes into Corona Borealis moving east at 2.6'/min near magnitude 14.0 when it's poorly placed for SE Texas. If I attempt observations 6 hours earlier, just prior to the onset of morning twilight, the big rock from space should be 63° up moving 2.4'/min in the east and ~mag 13.5. And still only slightly over 2LD away. The Moon is not a factor.

I'll have a go at this big rock (~200 meter 2010 XC15) which will be well for viewing in the early morning hours of December 27th. It will be moving >2'/min east thru Bootes high in the eastern sky (60+° near the beginning of astronomical twilight). Since this will be a 2LD pass, make sure to plot it for your location using the nearest element set.

[PMSchu]

As of today CNEOS still has the close approach of 2018 YK2 listed as occurring at  2022-Dec-26 01:21 ± 4_13:23 UT. They're using elements for the epoch 2023 Feb 25 on the Small Body Database Lookup page for this NEO.

Using the MPC's elements for 2022 Dec 20 0000 UT, ST4v predicts the close approach (to the nearest hour) on Dec 22@0100 EST (0600 UT) at 
772.2k km distant, 14.4 magnitude when it's moving through Lacerta at 223.7"/min.

It looks like this NEO hasn't been recovered yet as the time of close approach is very uncertain at ±4.5 days.

2010 XC15 still looks to be on track for its close approach on December 27.

Phil S.

[PMSchu]

There's still no change in the status of the NEO 2018 YK2 on the CNEOS website. The close approach is still listed as occurring on  2022-Dec-26 01:21 ± 4_13:23 UT.

Phil S.

[PMSchu]

According to the MPC the NEO 2018 YK2 was reacquired by the Catalina Sky Survey and several other observatories on 2022 Dec 24. The close approach of this NEO occurred on 2022-Dec-24 12:35 ± < 00:01 UT at a distance of 0.02502 AU. The Condition Code from CNEOS is now 0.

Using MPC's elements for 2022 Dec 26 00:00 UT ST4v predicts that this NEO reached a peak brightness of 16.9 magnitude on Dec 25 at 2100 EST when it was moving through Andromeda at 37.1"/min.

2010 XC15 is still getting ready for its close approach. ST4v predicts that it will reach peak brightness of 13.4 magnitude on the morning of Dec 27 ~0300 EST when it will be moving through Coma Berenices at 130"/min. This is a 'Rarity'=3 event.

Good hunting,

Phil S.

[bigmasterdrago]

I had complete cloud free skies b4 astronomical twilight Tuesday when I had a look at 2010 XC15. Skies were pristine and visible in the 13" at 250x high in the east. ST4 says mag 13.5. It seemed brighter but I did not try an estimate using comparison stars.

If it was 8" off in DEC vs Horizons, I was unable to see the error. It was indeed moving at >2'/min and was nicely placed in the eastern sky. It passed just over 3° from M3 and ~30' from 6th mag 3 Boo.

Finally, vindication for me that the software can be massaged to work with these fast moving close passes.

[PMSchu]

That's great news BMD. I'm glad that you got a chance to observe this one. As a 'Rarity'=3 event, they don't occur very often. This is the only one that I've seen since they began to include it on the CNEOS website.

Phil S.