#reflective nebula

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The Pleiades (Seven Sisters)

The open cluster M45 is only 444 light years from Earth, and yet as you'll see from this lovely image, the area has a dense dust cloud, that the stars are currently moving through, and which is being lit blue by the stars in the cluster, otherwise known as a reflective nebula.

The cluster got it's name Seven Sisters from the fact your average human can pick out around 7 of the largest stars in the cluster, those with excellent eye sight and in a very clear region away from light pollution and air pollution are thought to be able to see as many as 13-14, however in reality, the cluster houses over 1000 stars.

The cluster is thought to have been born around 75 - 150 million years ago, a blink of an eye in our galaxies story, and the dust and gas around it had been assumed to be the birth nebula, until more recently where it's been possible to detect and watch the stars as they move through the dust, and not along with it.

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NGC 2170

If I was naming this I'd be tempted to call it Skin of Evil, there's something about those dark dense dust tendrils, partly illuminated by a hot young blue star.

The nebula is only 2,700 light years from Earth in the constellation of Monoceros.

Such dense nebula hide many protostars, some can be seen peeping out the head and illuminating the dust through UV bombardment.

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Spooktober - Witch Head Nebula

To throw in a couple of spooky images this month, this one is particularly illuminating, as in a reflective nebula illuminated by the huge star Rigel, in the constellation of Orion.

Rigel is a binary system some 800 light years from Earth, although that has been hard to be certain, with some studies showing 550 up to 1000, and if you look closely under a telescope you can see it's tiny binary partner, although what you cannot see in this image, is that the tiny companion is actually 3 stars.

The blue colouration comes from Rigel, but also the dust in this nebular that reflects the blue light while absorbing the red light.

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vdB 9

Sidney van den Bergh's 1966 catalog (vdB) and 9th entry of reflective nebula is this beauty.

The object is 1,540 light years from Earth in the constellation of Cassiopeia.

The cloud is 24 light years across and in part glows blue from the star SU Cassiopeiae.

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The Dark Nebulae of Chamaeleon

To the south of the constellation of Chamaeleon lies a body of dust and gas that mostly conceals the stars behind it, making it a tricky object to image, unlike the emissions and reflective nebulae, but no less dramatic and capable of star formation.

Beta Chamaeleon is one such star, born inside the nebula and therefore shining light into the nebula which reflects back as a blue haze.

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Messier 78 - Reflection Nebula

Part of the Orion complex, 1,350 light years from Earth in the constellation of the same name, this 8 light year wide area of dust and gas reflects light back towards Earth, creating a blue /white light, and one of the brightest such reflective nebula's in our skies, although sadly still out of range of the naked eye, other parts of the Orion complex are not.

The dark areas are doing the opposite, they are obscuring the light behind them and are known as dark nebula.

The red areas are bodies of hydrogen excited by the UV light coming from the new born stars and glowing this colour.

pulling you begin to get an idea of the sheer size of the Orion structure which holds many catalogue objects.

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Corona Australis

Nebula is mostly hydrogen gas, and a small amount of metals (elements above helium) which tend to be covered as "Dust", but it's the dust that best reflect the light of the stars, and as the largest and most energetic of them are blue, you get these areas of blue haze. Hydrogen more often glows red when bombarded by UV light, the two colours together quite magical.

The area has a number of NGC objects 6726,6727,6729 but born of the same huge molecular cloud.

Our Milky Way has many such areas full of star birth, and as blue giants are not long lived, supernova and star death too.

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The Reflections of a Rock Star

When it comes to true rock stars, in Astronomy at least, you don't look much further than the blue B and O type stars, who live fast and die young ! But in their short lives, they light up the galaxy, and that includes the dust and gas that makes up the stars.

Reflective nebula are commonly blue, due to their association with the very new born stars birthed by the dust and gas in the first instance, with the most massive being the blue giant stars, that then return the favour by lighting them up with a blue hue, which is actually the light reflecting back towards us.

Pull back and you can see the amazing way these stars light up entire galaxies, like diamonds studded in amongst the other stars, as in the M97 below.

In amongst the blue diamonds you can also spot a pink/red pattern, this too is created by the very same blue giant stars, UV light bombarding the hydrogen gas and making it glow a pink red colour, and why so many emissions nebula are that very colour (see the Eagle Nebula below)