New observations confirm that there’s an Earth-size planet orbiting within the (theoretical) habitable zone of the very nearest star, Proxima Centauri
The existence of a planet the size of Earth around the closest star in the solar system, Proxima Centauri, has been confirmed by an international team of scientists including researchers from the University of Geneva (UNIGE). The results, which you can read all about in the journal Astronomy & Astrophysics, reveal that the planet in question, Proxima b, has a mass of 1.17 earth masses and is located in the habitable zone of its star, which it orbits in 11.2 days. This breakthrough has been possible thanks to radial velocity measurements of unprecedented precision using ESPRESSO, the Swiss-manufactured spectrograph – the most accurate currently in operation – which is installed on the Very Large Telescope in Chile. Proxima b was first detected four years ago by means of an older spectrograph, HARPS – also developed by the Geneva-based team – which measured a low disturbance in the star’s speed, suggesting the presence of a companion.
The ESPRESSO spectrograph has performed radial velocity measurements on the star Proxima Centauri, which is only 4.2 light-years from the Sun, with an accuracy of 30 centimetres a second (cm/s) or about three times more precise than that obtained with HARPS, the same type of instrument but from the previous generation.
“We were already very happy with the performance of HARPS, which has been responsible for discovering hundreds of exoplanets over the last 17 years”, begins Francesco Pepe, a professor in the Astronomy Department in UNIGE’s Faculty of Science and the man in charge of ESPRESSO. “We’re really pleased that ESPRESSO can produce even better measurements, and it’s gratifying and just reward for the teamwork lasting nearly 10 years.”
While amazing, the fact it's orbiting in the habitable zone of a red dwarf is a bummer. It's almost certainly tidally locked.
Venus is not tidally locked to the sun.
The fact that Proxima Centauri is a red dwarf is not a good thing. It means the planet is very likely tidally locked. The habitable zone around a red dwarf is very close to the Star. This new planet orbits 5 million miles away from Proxima, we orbit at 93 million miles from the sun to give you some idea how much closer it is.
Also, red dwarves are called “flare stars” because, well, they like to flare up. A lot.
Any planet in the habitable zone of a red dwarf has likely had its atmosphere stripped away. Habitable zone only means the surface of the planet can posses liquid water and host some sort of simple microbial life. Habitable zones are something of a misnomer especially when applied to red dwarves. They are the smallest of all main sequence stars so they are an outlier in many ways.
This is a very unlikely candidate for a habitable world. Interestingly, after 2.5 trillion years red dwarves turn into blue dwarves which can become quite stable and enter into a very habitable period. Blue Dwarves also have a higher luminosity so the habitable zone will move out from the Star and thaw new planets.
The universe will be extremely habitable in a few trillion years.
I’m really into astrobiology.
Edit: does this stuff sound cool? Cool! You should go out right now and buy this book:
Astrobiology: A Very Short Introduction
It’s on amazon. It’s ten dollars. It’s 100 pages and it’s amazing. It will completely catch you up on what we know about astrobiology.
*The book is now sold out. Sorry. But they have a few left in the “used and new” section.
Edit 2 electric boogaloo: The last question is considered by many to be the best sci fi short story ever written. It deals with timespans of trillions of years. I recommend everyone read it if you haven’t yet.