200,000 Degree Star Found at Center of NGC 6302

Astronomers at The University of Manchester's Jodrell Bank Centre for Astrophysics have discovered one of the hottest stars in the Galaxy - with a surface temperature of around 200,000 degrees, it is 35 times hotter than the Sun. Despite numerous attempts by astronomers across the world, the mysterious dying star at the heart of NGC 6302, the Butterfly nebula - one of the brightest and most beautiful of the planetary nebulae - has never been seen before. NGC 6302 lies within our Milky Way galaxy, roughly 3,800 light-years away in the constellation Scorpius. The glowing gas is the star's outer layers, expelled over about 2,200 years. The "butterfly" stretches for more than two light-years, which is about half the distance from the Sun to the nearest star, Alpha Centauri.The central star, which up to now could not be seen because it is hidden within a doughnut-shaped ring of dust, appears as a dark band pinching the nebula in the center. The thick dust belt constricts the star's outflow, creating the classic "bipolar" or hourglass shape displayed by some planetary nebulae.

The star's surface temperature is estimated to be about 200,000 degrees Fahrenheit, making it one of the hottest known stars in our galaxy. Spectroscopic observations made with ground-based telescopes show that even the gas surrounding the star is roughly 36,000 degrees Fahrenheit, which is unusually hot compared to typical planetary nebulae."This star was so hard to find because it is hidden behind a cloud of dust and ice in the middle of the nebula.

Using the recently refurbished Hubble Space Telescope (HST), a team of astronomers have shed new light on the nebula with a set of spectacular images. The images were taken to show off the new improved HST after it began work again in September this year. The Manchester astronomers were amazed to find that the images unexpectedly revealed the missing central star.

Astronomer's said "It's extremely important to understand planetary nebulae such as the Bug Nebula, as they are crucial to understanding our own existence on Earth". That is because the elements necessary for life, especially carbon, are created inside stars, and ejected into space as part of these planetary nebulae. Planets such as the Earth form from small dust particles, which also form within planetary nebulae. The cloud of dust and ice in the Bug Nebula contains the seeds of a future generation of planets." Finding the star was made possible by the Space Shuttle's final servicing mission of the HST, earlier this year. During the mission, astronauts installed the new Wide Field Camera 3 which was used to take these images. "How a star ejects a nebula like this is still a mystery. It seems most stars, including the Sun, will eject as much as 80 per cent of their mass when they finally run out of nuclear fuel at the end of their lives. Material that then goes on to help form the next generation of stars and planets.

These observations have shown that the star at the heart of the Bug Nebula is only about 2/3 as heavy as the Sun, but was several times heavier before it threw off its outer layers to form the nebula which had previously hidden it from our view.