Giant Stars : Heavenly Bodies

By James Anthony

Astronomers have discovered a group of stars

Now we know space is big … actually really, really big. And our sun is a huge blazing ball of fiery gas that dwarfs every planet on our solar system.

But imagine a star - which is what the sun is - 1500 times bigger than our solar system-heating globe.

It's true. Scientists have discovered three new supergiant stars that are so big they are mind-boggling actually.

The new discoveries are KW Sagitarii (9800 lightyears away), V354 Cephei (9000 lightyears) and KY Cygni (5000 lightyears). They sound a bit like motorbikes, but rest assured, they have much more power!!

Each of the trio is 1500 times bigger than our sun and to put that into perspective, if one happened to be in our solar system it would stretch half-way from Jupiter to Saturn.

Now, the sun is more than 100 times bigger in diameter than the Earth and about 1 million times its size. Multiply that by 1500 and you sort of get the picture. Think of a half-billion miles and you'll be getting there.

Astronomers found the supergiants, which are red in colour, in the Milky Way. They are moving towards the end of their lifetimes and are very bright and cold.

The scientists made their discovery using the National Science Foundation's 2.1-metre (84-inch) telescope at Kitt Peak National Observatory, near Tucson, Arizona, and the 1.5-metre (60-inch) star gazer at Cerro Tololo Inter-American Observatory, in the foothills of the Chilean Andes.

Putting together data with the aid of the latest computer technology, the astronomers were able to work out the temperature on the giants - about 3450 Kelvins - which was up to 10 per cent warmer than experts had expected. The Celsius temperature scale is defined by setting 0°C equal to 273.16 K.

Although some 300,000 times brighter than our sun, the supergiants are not the brightest stars in the universe - they can be 5 million times its brightness. Before kW Sagitarii, V354 Cephei, and KY Cygni were discovered the biggest known stellar body was MU Cephei, or Herschel's Garnet Star - about 650 times bigger than the sun.

AND, in an interesting development, one of our smaller near neighbours - Mars - may have had life on it only a few million years ago.

Images from European Space Agency's Mars Express Mission have allowed researchers to pick evidence of glacial movement, volcanoes and climate change. Scientists believe that Mars had water, lava and ice in relatively recent cosmic terms and therefore could well have had - or has - life.

A British researcher, John Murray, says there is a frozen expanse of water about the size of the North Sea on the planet and other evidence suggests below-surface icefields.

The discoveries have excited scientists who now think they have a good insight into the Martian climate and from there - with more study - they can really discover 'is there life of Mars?'

Links:
NASA website