The Sun is thought to have a twin somewhere, born not just in the same stellar nursery, but an almost identical twin , a binary companion made from the same stellar matter. And astronomers believe they have found it.
This possible twin of the Sun called HD 186302 is located approximately 184 light years away and if it is not its twin, it is almost certainly at least one lost brother of our star.
Most stars are born in groups that can number in the thousands in what we know as stellar nurseries, huge masses of clouds of gas and dust, pushed into groups that gradually collapse under their own weight, forming the early stages of stars. It is believed that the life of the Sun began in this way, 4.57 billion years ago.
Stars tend to end up alone in the galaxy, but most of them have at least one other partner. It is estimated that up to 85% of all stars could form binary pairs, or even triple or quadruple systems; and more than 50% of all Sun-like stars form binary pairs.
Solitaire Sun
Our Sun is a lone star, which makes it something of a weirdo. But there is scientific evidence to suggest that he had a binary twin at some point. Recent research suggests that most – if not all – stars are born with a binary twin.
Thus, the Earth could have had two suns. Where is that twin?
To date, only a few candidates have been identified. But a team led by researchers from the Portuguese Institute of Astrophysics and Space Sciences, armed with the best tools and a great chemical abundance of elements and astrometric data discovered HD186302, a special stellar brother. Incredibly similar to the Sun.
It is a G-type main sequence star, just a minute larger than the Sun, and of roughly the same surface temperature and luminosity. It also has extremely similar chemical elements, and roughly the same age, around 4.5 billion years.
It’s an even closer match than the F-type star HD162826, identified as a stellar sister in 2014.
“Since there is not much information about the Sun’s past, studying these stars can help us understand where in the galaxy and under what conditions the Sun was formed ,” said astronomer Vardan Adibekyan, leader of the work collected by the journal Astronomy & Astrophysics.
But there is more. The only place in the universe where we know for sure that life has formed is the solar system. That means the size, age, temperature, luminosity, and chemical composition of the Sun are compatible with life as we know it. So it seems plausible that planets orbiting other stars with these same qualities (stellar brothers) could also have developed life.
“Some theoretical calculations show that there is a non-negligible probability that life will spread from Earth to other planets or exoplanetary systems, during the period of the last intense bombardment”, clarifies o Adibekyan.
“If we are lucky, and our candidate brother has a planet, and the planet is rocky type, in the habitable zone, and finally, if this planet were ‘contaminated’ by the seeds of life from Earth, we would have what we dreamed of: an Earth 2.0, orbiting a Sun 2.0 “.
AI astronomers are now making plans to look for signals from any planet that may be in orbit around HD186302.
Reference: V. Adibekyan et al. The AMBRE project: searching for the closest solar siblings, Astronomy & Astrophysics (2018). DOI: 10.1051 / 0004-6361 / 201834285
