A Universe Brimming with Red Dwarfs

This week’s OOTW features Lightbulb500’s OOTD posted on the 4th of December 2010.

This star, with a mass of around half of that of our own star and a temperature many degrees cooler; is a red dwarf. They are the most common stars in the universe, 85% of our galaxy’s stellar population is composed of red dwarfs and it was thought that there was 1×10^23 (or 100 sextillion) in the universe. They are also the longest lived with a lifespan of up to ten trillion years!

The number of red dwarfs in the universe has been recently changed to a much higher number, as Lightbulb500 writes:

[…]  New data that confirms the presence of red dwarfs in eight elliptical galaxies between 50,000 and 3 million light years distant. As well as confirming their presence the number of red dwarfs per galaxy has been calculated and reveals that these elliptical galaxies contain 20 times the number of red dwarfs as the Milky Way!

Such a large jump in the number of red dwarfs in elliptical galaxies has necessitated a ‘slight’ revision to the number of stars inhabiting our universe.

The figure has been revised from 100 sextillion or (if I may have an infant moment) 100,000,000,000,000,000,000,000, or 1×10^23 if you like standard form to 300 sextillion – It has been tripled!

Such an increase has other knock on effects – more stars means more ‘normal’ matter so the universe would ‘need’ less dark matter to ‘work’.

It could also have an effect on how dark matter is concentrated around galaxies.