Our asteroids, Part One

“Our” means me and some friends.

Minor planets, when discovered,get temporary designations. Later, when there is enough information about their orbits, they get permanent numbers. Later, they may get names.

The first four were the large asteroids (1) Ceres, (2) Pallas, (3) Juno, and (4) Vesta. I usually make it easier by omitting the parenthesis marks.

The permanent numbers have passed 895000. They grow rapidly, because minor bodies are now swept up as by-products of automated sky surveys by large observatories. They will soon pass a million.

On July 7, I was amazed to learn (from Deborah Byrd of EarthSky.org) that a flying mountain designated as 1988 PE had become (21008) Ottewell.

It was the 13th of 39 new names announced in a bulletin of the International Astronomical Union’s Working Group on Small Body Nomenclature. The nominating, and the flattering description of the astronomical side of me, had been written by Kelly Beatty, who is well known to readers of Sky & Telescope as one of its senior editors.

The thing is a Main Belt asteroid, estimated to be about 4 kilometers wide, so I can picture it as something like the Rock of Gibraltar. It was one of the numerous discoveries (on 1988 August 9) by Eleanor Helin at Palomar Mountain observatory.

I wanted to find orbital elements so as to be able to plot a chart. This was more of a struggle than I expected, and let into a new bout of programming which enables me to find elements in another of the Minor Planet Center’s enormous data files and reformat them into lines I can add to my own catalog.

A making-it-easier strategy that I’ve used all along  is names of only up to four characters by which to refer to the moving bodies: “EART”; “JUP”; “1” instead of “(1) Ceres.” So my asteroid is “Guy” in the file that instruct programs how to make calculations or draw illustrations. I’m not fond of either of my names. I’ve been told that “Ottewell” suggests short and fat, whereas I am long and thin.

Here is the path of rock 21008 across the sky in 2026.

A chart like this is inconveniently wide. In a year when it becomes most distant from us, travels around beyond the Sun and going through Sun-conjunction, a Main Belt asteroid makes a long obscure path. This is like the behavior of Mars, on the outer edge of the Main Belt.

The better way is to make a more compact, yet larger-scaled, chart for the time around opposition, when the planet goes into its retrograde loop because we are overtaking it.

This asteroid has oppositions at 2026 Mar 4, 2027 Oct 16, 2029 Jan 22, and 2030 May 10. The first of these has already passed, so here is a chart for the 2027 opposition,

I’m not promising you’ll have much luck finding the 16.6-magnitude speck! And I don’t think it will earn much excitement, unless it gets nudged by some other rock into a dangerous near-Earth orbit, or until it becomes colonized and farmed as part of Freeman Dyson’s “archipelago of the asteroids“.  As honorary member of its council, I would object to letting it be a tax haven like Gibraltar.

Among the myriad other people with their names on minor planets are at least eight I feel association with, having met or corresponded with or been helped by them. For starters, 2925 Beatty and 3505 Byrd. I have their orbital elements. Watch this space.