ESO and Hubble image of orphan star in 30 Doradus

A young star flees the nest (Image credit: NASA, ESA, ESO et al)

Astronomers in search of really, really big stars look to the Tarantula Nebula. Also known as 30 Doradus (or even NGC 2070), this is a very active star-forming region in the Large Magellanic Cloud (about 170 000 light years from us).

Just how big are the stars in the Tarantula? Imagine taking a hundred stars the same as our Sun (which is one of the biggest and brightest stars in the galaxy) and mashing them together into one humongous star. There are several stellar titans this size in the nebula. Such giants live short and violent lives which end in apocalyptic explosions called supernovae. Abundant supernovae on top of the usual ferocity which accompanies starbirth means that this nebula is a turbulent, unsettled place.

Recent observations by an international team of astronomers using the HST and Very Large Telescope suggest a star has escaped the violence. This star is unusual in many ways, 90 times as big and ten times as hot as the Sun, it is blasting out the most powerful stellar winds yet seen. It is also hurtling through space at about 400 000 km/h (think about that speed for a moment; a spaceship travelling to the Moon from Earth at that speed would get there in an hour!)

This star would fit in perfectly with the stars of the nebula, specially those in the central star cluster, called R136, but it is some 375 light years away. The theory is that this a stellar runaway, ejected by its siblings. It may have originally been part of a binary system and been blown away when its partner exploded as a supernova. Alternatively, it may have been kicked out by gravitational interactions from some of the more massive stars in the cluster in a process not unlike the gravity assists used by spacecraft. There is evidence of other fast moving stars in the vicinity of the nebula, perhaps it is spitting out its offspring.

This orphaned star will live as fast as it is moving, eventually exploding. All that will remain will be a black hole careering through the void.

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4 Comments

Clara · February 6, 2011 at 01:23

cool! has there been any other cases like this?

    admin · February 7, 2011 at 08:00

    Other “runaway stars” are known. Some are ejected from young clusters like this one, others like Mu Columbae are the result of double star systems getting too close and pulling each other apart, others are blasted away when a companion star denotes as a a supernova (see http://www.eso.org/public/news/eso9702/).

How big is the Largest Star · February 21, 2015 at 03:24

[…] can be seen as the biggest and brightest star at the centre of a large cluster of stars in the Tarantula Nebula, in the constellation of Dorado.  This cosmic kingpin weighs in at an impressive 265 solar masses. […]

What are the Largest Stars in the Universe? | Astronotes · October 15, 2013 at 02:54

[…] can be seen as the biggest and brightest star at the centre of a large cluster of stars in the Tarantula Nebula, in the constellation of Dorado.  This cosmic kingpin weighs in at an impressive 265 solar masses. […]

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