Billions of these small stars could be permeating the Milky Way

Nov 28, 2013 09:53 GMT  ·  By

With recent studies confirming the widespread distribution of red dwarfs throughout the Milky Way, astronomers have begun conducting a series of investigations meant to determine whether or not these small stars can host exoplanets in their habitable zone.

The latest conclusions appear to indicate that life may very well develop around these small celestial fireballs.

Surveys have determined that around 64 percent of all stars around the Sun are red dwarfs, but the low brightness these objects display makes them very difficult to detect in bulk with existing telescopes.

Red dwarfs range in mass from 0.075 solar masses – which is the upper mass limit for failed stars called brown dwarfs – to 0.5 solar masses. By comparison, the Sun is a yellow dwarf, a slightly larger type of star. The cores of red dwarfs only produce temperatures of around 4,000 Kelvin, compared to the Sun's 5778 Kelvin.

These objects produce energy through nuclear fusion, by combining hydrogen atoms into helium atoms, via the proton–proton (PP) chain mechanism. Though their fuel supply is more limited than that of yellow dwarfs, these objects can live for much longer periods of time, Space reports.

According to astrophysicists, the low burning temperature of red dwarfs enable them to live for trillions of years, as opposed to yellow dwarfs like the Sun, whose main sequences only last for 10 billion years.

Studies have revealed that, despite their small size, red dwarfs can have planets in orbit. Gas giants such as Saturn and Jupiter are relatively rare, but smaller worlds similar to Earth are more common. This is a good sign in our quest to find potentially habitable extrasolar planets, astronomers say.

Planets around such stars would have to be located very close to their surface in order to experience temperatures that support liquid water, which means that they would be bathed in radiations, or would be tidally locked to their parents star. This is why experts thought these worlds could not support life.

However, new studies indicate that some exoplanets could develop in such a way that they might not be subjected to radiations or being tidally locked. Given the high number of red dwarfs in the Milky Way (more than 60 billion by the last count), the chances of life appearing on such worlds is fairly high.

These investigations therefore suggest that our search for extraterrestrial life should be focused more on red dwarfs, and less on stars the size of the Sun, or larger.