CONSTELLATIONS OF THE MONTH - Pictor

John Howard

Lacaille created Equuleus Pictoris, also known as Pluteum Pictoris, in 1752. According to Hartung, Gould (not our Gould!) shortened the name to Pictor in 1877. Chambers' 1881 edition of "Cycle of Celestial Objects" calls it Pictoris, as does Webb's 1868 "Celestial Objects for Common Telescopes". J. Norman Lockyer doesn't mention it in his 1871 edition of "Elementary Lessons in Astronomy".

The cloud cleared sufficiently on 2nd March for me to have a look at Pictor through an 8-inch Vixen.
There are a couple of very nice double stars: iota Pic being a well-separated pair of white stars, and theta Pic a very wide, pale yellow and pale blue combo. Each pair is about equal in magnitude, and has the eyepiece field pretty much to itself. The broad swathe of the Milky Way swept over my head (hey, I'm a poet) while Pictor is out of the mainstream in the part of the sky where stars generally aren't.

Pictor is easy enough to find - it's between Canopus and the LMC - but not easy to see. Its brightest star these days is alpha at mag 3.3, but in 1925 RR Pictoris went Nova and reached mag 1.2. RR Pic no doubt is a close double, with the companion being a white dwarf or neutron star. (Aside: what happens to the protons in a neutron star? Answer, from "The Cambridge Atlas of Astronomy": gravity is so strong that it pushes electrons inside atomic nuclei, neutralising protons to produce neutrons. There is an upper mass limit for neutron stars: the Landau-Oppenheimer-Volkoff limit of about three solar masses. Above this value, degenerate neutrons begin to turn relativistic.)

Another double, which I couldn't split on the night, is mu Pic.

Two interesting objects in this constellation are beta Pic, which has a disk of planet-forming material around it (invisible to me) and Kapteyn's Star, which is whizzing through space at 300 km/sec relative to the Earth. At about 13 light years distance, that translates to an eyepiece width (one degree) every 415 years. I detected no movement!

Beta Pictoris' planetary disk is far too faint to see, but not the remains of our Sun's disk : that night I saw Saturn, Jupiter and Venus, and nearly saw Hygiea.