Cycles of NEO Passages

[bigmasterdrago]

Looking back a little over 100 years there is not a random passing of NEOs under 0.5LD. The peak seems to occur in late March and late September, near the equinoxes. Any thoughts on if this is just a selection disguised by the larger number of observatory (surveys) that have good access to the ecliptic?

[PMSchu]

Might it be that around the equinoxes, the nights are approximately equal length in both northern & southern hemispheres. That would give scopes in both hemispheres ~10 hours/night to make their observations. Full moon really hammers the number of new NEOs that are reported by the MPC each day. Since we're near Harvest Moon, there have been several days that had no new MPs added to the data file of NEAs at Today's Epoch.

Short nights would affect observatories experiencing short summer nights the same way - fewer NEOs detected.

Just a thought,

[PMSchu]

Since the Harvest Moon has passed, the MPC has been recording more NEOs. About 65 objects in the last 3 days. They're already up to 2022 SZ2. 2022 SA was discovered on Sep 16.

They've been very busy.

Phil S.

[bigmasterdrago]

Well, when inquiring minds ask, it was suggested to me to plot asteroid total discoveries instead. To see any variation year to year monthly. It was suggested that the scatter year to year would have considerable overlap month to month. Asteroid discoveries appear to be slim in summer time when the galactic center (Milky Way) and the region of opposition (ecliptic) is far south - no deep asteroid surveys in the south. Much of the asteroid discovery work is being done by scopes in southern Arizona (Catalina) who stop asteroid work for maintenance work due to weather. So possibly the same pattern will show up for all and not just NEOs. Something more to study. Too much fun!

[PMSchu]

I'm surprised that there aren't NEO searches in Hawaii & Chile as well.

Phil S.

[bigmasterdrago]

Appears to be only amateurs in Chili. Pan-STARRS in Hawaii but the big boys are Catalina and followups by Mt. Lemmon.

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Interesting stats: https://catalina.lpl.arizona.edu/science...statistics

And a list of not so well known observatory discoveries: https://en.wikipedia.org/wiki/List_of_as...ervatories

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This monster should make big changes in the south survey world.

https://www.lsst.org/

One of its scientific goals is the mapping of small objects in the Solar System, particularly near-Earth asteroids and Kuiper belt objects. LSST is expected to increase the number of cataloged objects by a factor of 10–100. It will also help with the search for the hypothesized Planet Nine.

[PMSchu]

The MPC has been adding NEOs at a rapid rate since the Harvest Moon has passed. They added another 27 objects today. They're up to 323 for September & 2099 for 2022 so far. 29,923 NEOs total. Looks like they'll blow through 30,000 in October.

Phil S.