A trio of Trans-Neptunian Objects

[lukebl]

I've had a go at capturing some interesting distant trans-Neptunian objects. These three are well-placed at the moment. The second two are quite easy to capture, but the first was tricky, being pretty dim (mag 19.5) and at a relatively low altitude. All positions were confirmed by Astrometrica. The field of view of the images is 38.6 x 29.1 arcmin.

This is 90482 Orcus.

Until this week I'd never heard of it. It's similar, but smaller than, Puto with a diameter of 910km. It occupies a similar 247 year orbit but at a different orbital inclination, and even has a similarly large moon. Apparently regarded as the 'anti-Pluto'. Discovered in 2004. Named after the Roman god Orcus, punisher of the condemned in the Roman underworld. Nice job.

17 x 5 minute exposures, binned 2x, Omegon RC8 (1624mm FL, f/8). Atik 383L+. Very tricky to make out, but distinct on the original images. I was plagued with satellite trails, which can still be seen.

This is 136472 Makemake, the brightest trans-Neptunian object after Pluto with a 306 year orbit. Makemake was one of the objects whose discovery prompted the International Astronomical Union to reconsider the definition of a planet and to create the new group of dwarf planets. Effectively demoting poor Pluto, which as we all know turns out to be awesome.

12 x 2 minute exposures.

Here's an animation showing its position on 5th and 10th April

Finally, this is 136108 Haumea.

It has a very fast rotation for a big object, about 4 hours, which is apparently why it has an ellipsoid shape. There was some controversy about its discovery in 2004. After the discovery was announced by an observatory in Hawaii, a Spanish team claimed that they discovered it first. It turned out that the Spanish team used early leaked data and found it on some earlier images. I think there's some bitterness there!

Both Haumea and Makemake are near Arcturus right now.

Here's an animation showing its position on 5th and 10th April