A giant Super-Earth just six light years away could still have the potential to harbor primitive life, researchers have found.
Barnard b (or GJ 699 b) is a recently discovered Super-Earth planet orbiting Barnard’s Star, making it the second nearest star system to the Earth.
The planet is believed to be extremely cold, with temperatures is similar to Jupiter’s moon, Europa, at around -150°C (-238°F).
However, researchers say it could have a large, hot iron/nickel core and enhanced geothermal activity, which would allow life to flourish.
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A frozen ‘super-Earth’ has been discovered orbiting Barnard’s Star, the closest single star to the sun. Despite surface temperatures of around -150°C (-238°F), scientists believe pockets of liquid water could lie beneath the ice capable of harbouring life (artist’s impression)
‘Geothermal heating could support ‘life zones’ under its surface, akin to subsurface lakes found in Antarctica,’ said Villanova University Astrophysicist Edward Guinan at the 223rdmeeting of the American Astronomy Society (AAS) in Seattle, WA.
‘We note that the surface temperature on Jupiter’s icy moon Europa is similar to Barnard b but, because of tidal heating, Europa probably has liquid oceans under its icy surface.’
‘If water is present, geothermal heating (volcanic plumes, vents etc.) could result in liquid water ‘life zones’ under a possible icy surface,’ the pair wrote in their accompanying paper.
‘This much like Jupiter’s icy moon Europa that is heated by tidal heating rather than from geothermal energy.’
‘Barnard’s Star has been on our radar for a long time,’ Guinan said.
‘The most significant aspect of the discovery of Barnard’s star b is that the two nearest star systems to the Sun are now known to host planets.
‘This supports previous studies based on Kepler Mission data, inferring that planets can be very common throughout the galaxy, even numbering in the tens of billions,’ Scott Engle, who co-authored the paper, noted.
The newly detected planet, Barnard’s Star b (artist’s impression), is thought to be rocky and at least 3.2 times more massive than the Earth. It circles a cool red-dwarf star, smaller and older than the sun, completing one orbit every 233 days
‘Also, Barnard’s Star is about twice as old as the Sun – about 9 billion years old compared to 4.6 billion years for the Sun.
‘The universe has been producing Earth-size planets far longer than we, or even the Sun itself, have existed.’
Barnard’s Star b, with a mass just over three times that of the Earth, orbits Barnard’s Star, a red dwarf star, every 233 days and at roughly the same distance that Mercury orbits the Sun.
It passes near the dim star’s snow line.
Although very faint, it may be possible for Barnard b to be imaged by future very large telescopes, according to Guinan.
‘Such observations will shed light on the nature of the planet’s atmosphere, surface, and potential habitability,’ he added.
Despite surface temperatures of around -150°C (-238°F), scientists believe pockets of liquid water could lie beneath the ice capable of harbouring life.
The newly detected planet, Barnard’s Star b, is thought to be rocky and at least 3.2 times larger than the Earth.
Its host, Barnard’s Star, is six light years from Earth – hardly any distance on astronomical scales – with a luminosity 0.0035 times that of the sun.
The only closer star system is Alpha Centauri, which consists of three stars bound together by gravity, around four light years away.
The planet’s existence was confirmed after two decades of observations using several different ground-based telescopes and instruments.
One of them was the new state-of-the-art planet-hunting instrument Carmenes at the Calar Alto Observatory in Spain.
Even the most powerful telescopes in use today would not be able to image Barnard’s Star b directly.
WHAT IS BARNARD’S STAR?
Barnard’s Star is named after Yerkes Observatory’s E.E. Barnard (1857-1923), who discovered it in 1916.
It is close to not being visible to the naked eye, even though at a distance of just six light years it is the second closest star to the Earth – if you consider the three stars of Alpha Centauri system, including Proxima, as a unit.
That is just what you would expect from a dim, low mass, class M (M4) dwarf.
At 3,170 Kelvin (2,896°C / 5,246°F), this dim dwarf has a luminosity 0.0035 times that of the sun, most of the most of it in the infrared end of the spectrum.
These emissions show it has a diameter only 20 per cent that of the sun and a mass 17 per cent of our nearest star.
#Far from rare, the great majority of stars fall into the M dwarf category, they are just so faint – like Proxima Centauri – that they are not visible to the naked eye.
Barnard’s Star is six light years from Earth – hardly any distance on astronomical scales – a dim dwarf with a luminosity 0.0035 times that of the sun. The only closer star system is Alpha Centauri 4.4 light years away
Barnard’s Star is old, born before exploding stars had enhanced the amount of interstellar metals to that seen today, with a metal content only 10 per cent that of the Sun.
Its age is also attested to by its long rotation period of 130 days – stars slow down as they age – which is five times longer than the sun’s.
Barnard’s Star still has some magnetic activity, occasionally popping a flare caused by the release of magnetic-field energy, has an active X-ray corona heated magnetically to two million Kelvin – as does the Sun – and starspots, from which the rotation period is inferred.
Barnard’s low internal temperature and resulting feeble energy-generation rate give it an incredibly long life.
Indeed, no class M dwarf ever born in all the history of the Galaxy has ever died.