Tuesday, 16 February 2016

M33, the Triangulum Galaxy

It's been raining a lot for the past couple of days here in Northern Italy and on top of that there's a bright crescent moon around which would seriously mess up any attempt to make an observation anyway, so here's a post about a sketch I've made a few months ago and which fits in nicely with what I wrote in my previous message. Messier's 33rd object lies a little below the Andromeda galaxy in the autumn sky. It's the third major galaxy in our Local Group, together with Andromeda and our own, but unlike its much more famous big brother, the Triangulum galaxy's a fairly difficult object to observe. That's because we see it face-on and therefore its total brightness is spread over a much greater surface. Under a perfect sky it should still be visible to the naked eye and in that case it would probably be the furthest object we can see without a telescope. Its distance is estimated at 2,7 million lightyears, hence a bit further than the Andromeda galaxy to which it's a close, smaller companion. Small binoculars'll probably only reveal its core as a faint little patch. Bigger binoculars or telescopes will show you hints of its obvious spiral structure, but in order to have a really good look you require a telescope of 12" or up. Perhaps I was too anxious to try out a new pair of eyepieces I've bought for my soon-to-arrive mega-binoculars and as such I may have overdone the magnification of this object in my Nexus 100's. But in the end I did see a fairly large amount of detail.

The Triangulum galaxy derives its nickname from the constellation in which it resides. Some astronomers also refer to it as the Pinwheel galaxy, due to its obvious spiral shape, but most agree that this nickname should be reserved for M101, another face-on galaxy with a much 'cleaner' spiral structure. There's a clear gravitational interaction with the Andromeda galaxy and the most likely scenario predicts that in a distant future it'll be absorbed by it's big brother, fuelling the latter with fresh hydrogen to form new stars, before Andromeda eventually collides with our Milky Way. Interesting to note is the patch to the left of the core, at the tip of the brighter part of that spiral arm. This is a gigantic hydrogen region, designated NGC604, over 40 times the size of the Orion nebula and more than 6.000 times as bright! In other words, if it were at the same distance as the Orion nebula it would shine brighter in our sky than Venus! Not only is it one of the largest hydrogen complexes in our Local Group, it's also one of the most active. The Hubble space telescope's already identified hundreds of newborn stars inside of it, and since it's still a fairly young complex with its age estimated at only 3,5 million years, we can expect that its star cluster will still grow exponentially. When I'll get my new telescope I'll surely make a detailed sketch of that collossal gas cloud. In the meantime, I hope that you enjoy my sketch of this fascinating galaxy.

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