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The MPC has switched to 2022 August 9 Epoch
Hi All,

The MPC has finally switched to using the epoch 2022 August 9 for their MP orbital elements in place of the 2022 January 21 epoch that they've been using since around October 2021. I just noticed that the CNEOS website had switched to the new epoch & suspected that the MPC had finally made the change. 

If you've downloaded the MPCORB file more than a week ago & have the 2022 Jan 21 epoch for your MP orbital elements, you might want to download the updated elements. There are ~1.2E6 objects in the file, if you download all of the object categories. SkyTools allows you to choose which types of MPs to download, if you don't want them all.

The 'Rarity' 2 close approach of (349068) 2006 YT13, a 0.496km rock is predicted to occur on July 19, but it will be 0.45 AU distant.

Another could arrive at any time though.

Phil S.
Hey Phil. Dot your calendar with a * on ~Sept. 1 for the big rock pass of Cacus (161989). When it had a 6LD pass on Sept 2 1941, it was 9th magnitude. This pass will be more like 22LD. It should pop high in the dark sky at ~13.5 mag several nights in a row beginning end of August for us northern hemi folks. Looks like ~20"/min speed. Orbit uncertainty = 0. Discovered 1978, Catalina Sky Survey a few days ago. Over 1300 observations.

Not a screamer or fireball, but at this point, I get excited about anything as bright as 13th mag!!
Thanks BMD,

That's past the 60 day window that I've set for the CNEOS website. 13.5 mag is unusually bright for one of these buggers. So many are 17.5 to 20 mag  Sad.

Phil S.
I had to look up the mythological Cacus.

I guess the asteroid is named after him. From Wiki:

161989 Cacus (prov. designation: 1978 CA) is a stony asteroid, classified as near-Earth object and a potentially hazardous asteroid of the Apollo group, approximately 1 kilometer in diameter. It was discovered on 8 February 1978, by German astronomer Hans-Emil Schuster at ESO's La Silla Observatory in northern Chile.[2] Its orbit is confined between Venus and Mars.

This minor planet was named from Roman mythology, after Cacus, a fire-breathing monster, which was killed by Hercules.[2] The official naming citation was published by the Minor Planet Center on 24 November 2007 (M.P.C. 61270).[10]
At 1-2 km I hope it never breathes any fire on us. That would leave a mark.

Phil S.
It does have an interesting orbit for a PHA, has an inclination of 26°. Pretty close to where it is at in its orbit today at highest. Interesting.


It orbital position when closest to me on Sept 1, 2022.

Very nice. Can you show the plots for both dates ~parallel to the y axis for comparison? The shift in orienation from ~30° above the xy plane to parallel to the z axis is confusing.

Still some nice plots though, thanks.

Phil S.
Not sure what we need but I did a look straight down the z-axis for the two date (two screen shots) - now and close approach. Hope that is less confusing.


An BTW, the next time this big rock gets as close as it was in 1941 in on Sept 5, 2216, 6.6LD, Sept 3, 2147, 9.6LD, Sept 4, 2066, 17.6LD and Sept 5, 2091, 18LD. Always in September.
Thanks, that's easier to compare things. As far as the 2216 approach, I think I'm going to miss that one.

It looks like it crosses the plane of the earth's orbit in September & is ~1AU from the sun too.

Interesting plots.

Phil S.

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