Earth-like planet around Proxima Centauri discovered

August 15, 2016 by Matt Williams, Universe Today
Artist’s impression of a sunset seen from the surface of an Earth-like exoplanet. Credit: ESO/L. Calçada

The hunt for exoplanets has been heating up in recent years. Since it began its mission in 2009, over four thousand exoplanet candidates have been discovered by the Kepler mission, several hundred of which have been confirmed to be "Earth-like" (i.e. terrestrial). And of these, some 216 planets have been shown to be both terrestrial and located within their parent star's habitable zone (aka. "Goldilocks zone").

But in what may prove to be the most exciting find to date, the German weekly Der Spiegel announced recently that astronomers have discovered an Earth-like planet orbiting Proxima Centauri, just 4.25 away. Yes, in what is an apparent trifecta, this newly-discovered exoplanet is Earth-like, orbits within it's sun's habitable zone, and is within our reach. But is this too good to be true?

For over a century, astronomers have known about Proxima Centauri and believed that it is likely to be part of a trinary star system (along with Alpha Centauri A and B). Located just 0.237 ± 0.011 light years from the binary pair, this low-mass is also 0.12 light years (~7590 AUs) closer to Earth, making it the closest star system to our own.

In the past, the Kepler mission has revealed several Earth-like exoplanets that were deemed to be likely habitable. And recently, an international team of researchers narrowed the number of potentially-habitable exoplanets in the Kepler catalog down to the 20 that are most likely to support life. However, in just about all cases, these planets are hundreds (if not thousands) of light years away from Earth.

Knowing that there is a habitable planet that a mission from Earth could reach within our own lifetimes is nothing short of amazing! But of course, there is reason to be cautiously optimistic. Citing anonymous sources, the magazine stated:

"The still nameless planet is believed to be Earth-like and orbits at a distance to Proxima Centauri that could allow it to have liquid water on its surface—an important requirement for the emergence of life. Never before have scientists discovered a second Earth that is so close by."

In addition, they claim that the discovery was made by the European Southern Observatory (ESO) using the La Silla Observatory's reflecting telescope. Coincidentally, it was this same observatory that announced the discovery of Alpha Centauri Bb back in 2012, which was also declared to be "the closest exoplanet to Earth". Unfortunately, subsequent analysis cast doubt on its existence, claiming it was a spurious artifact of the data analysis.

However, according to Der Spiegel's unnamed source – whom they claim was involved with the La Silla team that made the find – this latest discovery is the real deal, and was the result of intensive work. "Finding small celestial bodies is a lot of hard work," the source was quoted as saying. "We were moving at the technically feasible limit of measurement."

The article goes on to state that the European Southern Observatory (ESO) will be announcing the finding at the end of August. But according to numerous sources, in response to a request for comment by AFP, ESO spokesman Richard Hook refused to confirm or deny the discovery of an exoplanet around Proxima Centauri. "We are not making any comment," he is reported as saying.

What's more, the folks at Project Starshot are certainly excited by the news. As part of Breakthrough Initiatives – a program founded by Russian billionaire Yuri Milner to search for intelligent life (with backing from Stephen Hawking and Mark Zuckerberg) – Starshot intends to send a laser-sail driven-nanocraft to Alpha Centauri in the coming years.

This craft, they claim, will be able to reach speeds of up to 20% the speed of light. At this speed, it will able to traverse the 4.37 light years that lie between Earth and Alpha Centauri in just 20 years. But with the possible discovery of an Earth-like planet orbiting Proxima Centauri, which lies even closer, they may want to rethink that objective.

As Professor Phillip Lubin – a professor at the University of California, Santa Barbara, the brains behind Project Starshot, and a key advisor to NASA's DEEP-IN program – told Universe Today via email:

"The discovery of possible planet around Proxima Centauri is very exciting. It makes the case of visiting nearby stellar systems even more compelling, though we know there are many exoplanets around other nearby stars and it is very likely that the Alpha Centauri system will also have planets."

Naturally, there is the desire (especially amongst exoplanet enthusiasts) to interpret the ESO's refusal to comment either way as a sort of tacit confirmation. And knowing that industry professionals are excited it about it does lend an air of legitimacy. But of course, assuming anything at this point would be premature.

If the statements made by the unnamed source, and quoted by Der Speigel, are to be taken at face value, then confirmation (or denial) will be coming shortly. In the meantime, we'll all just need to be patient. Still, you have to admit, it's an exciting prospect: an Earth-like planet that's actually within reach! And with a mission that could make it there within our own lifetimes. This is the stuff good science fiction is made of, you know.

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Azrael
4.6 / 5 (10) Aug 15, 2016
Oh, Wow. If it's confirmed that's an incredibly fortuitous find.

I hope we can build a reliable, light-weight craft that can get there and actually return data. I'll be well into middle-age before it gets there, and it would be a tremendous shame if the probe died in transit, or suffered an antenna or camera failure, as I likely wouldn't survive to see a second probe arrive there.

Human lifespans are so terribly limited.
Benni
1.6 / 5 (7) Aug 15, 2016
The nearest star is Proxima Centauri at a distance of 4.2 light years. At a speed of 150,000 miles per hour from a passive slingshot maneuver, it would take about 17,900 years to reach this star.

Jeffhans1
5 / 5 (5) Aug 15, 2016
Hawking and Milner announced earlier this year that they are working on a method of laser launching small ships up to 20% of the speed of light to make the trip much quicker. Look up the Breakthrough Starshot for more details.
geokstr
5 / 5 (4) Aug 15, 2016
Hawking and Milner announced earlier this year that they are working on a method of laser launching small ships up to 20% of the speed of light to make the trip much quicker. Look up the Breakthrough Starshot for more details.

4.2 LY at 20% Light Speed is 21 years.

However, how long does it take to go from 0 to 20% of LS and then to decelerate if they want to stay and study the system? I imagine that might double the transit time.
barakn
2.8 / 5 (5) Aug 15, 2016
This is not science, this is rumor.
Phys1
4.4 / 5 (7) Aug 15, 2016
The nearest star is Proxima Centauri at a distance of 4.2 light years. At a speed of 150,000 miles per hour from a passive slingshot maneuver, it would take about 17,900 years to reach this star.

My first reaction: Benni actually calculated something! Could it be possible ?
Then came doubt and suspicion, confirmed by a google search.
Benni plagiarized the astronomer Dr. Sten Odenwald onhttp://www.astron...306.html .
EMC2
1 / 5 (6) Aug 15, 2016
A planet we could reach in our lifetime? Are you high or stupid? It would take thousands of years to reach it with today's technology.
Mark Thomas
4.3 / 5 (6) Aug 15, 2016
"Benni plagiarized the astronomer Dr. Sten Odenwald"

Who also got it wrong. It would take ~19,000 years traveling at 150,000 mph to traverse 4.2 light years.

"A planet we could reach in our lifetime? Are you high or stupid?"

No need to be nasty, the author was referring to a postage stamp-sized probe driven by huge lasers envisioned in "Project Starshot." But I have to agree that plan is unconvincing.

"Naturally, there is the desire (especially amongst exoplanet enthusiasts) to interpret the ESO's refusal to comment either way as a sort of tacit confirmation."

If it were a total falsehood, they should have denied it. So they found something interesting but they want to be sure this time so they don't get burned again like they did with Alpha Centauri Bb, which apparently does not exist. I hope they take it every bit as seriously as the gravity wave folks did before they made their historic announcement.
dan42day
5 / 5 (4) Aug 15, 2016
Better to say, "A planet we could reach with technology that we could realistically envision in our lifetime."
HeloMenelo
3.4 / 5 (5) Aug 16, 2016
we need that warp drive
bschott
1 / 5 (4) Aug 16, 2016
we need that warp drive

Why don't you design one that works on banana fuel there monkey boy?
katesisco
1 / 5 (1) Aug 19, 2016
Confused because W Thornhill said that his theory calls for a red/brown dwarf to have planets inside its 'glow' and these planets would not see a starry sky but just a dim red atmosphere. So how did our telescopes pick up a planet inside the stars 'glow?'
DrItazura
not rated yet Aug 19, 2016
Very irresponsible to print this story before it is officially released.
jonesdave
5 / 5 (1) Aug 19, 2016
Confused because W Thornhill said that his theory calls for....


That's where your confusion comes from; listening to anything Thornhill has to say!
jonesdave
5 / 5 (2) Aug 19, 2016
Confused because W Thornhill said that his theory calls for a red/brown dwarf to have planets inside its 'glow' and these planets would not see a starry sky but just a dim red atmosphere. So how did our telescopes pick up a planet inside the stars 'glow?'


Well, any planet close enough to be in the HZ of a red dwarf will be tidally locked. So one hemisphere will definitely never see stars (other than its host). The other hemisphere would be in permanent darkness, and would see plenty.
jonesdave
5 / 5 (3) Aug 19, 2016
So how did our telescopes pick up a planet inside the stars 'glow?'


Presumably by radial velocity. That how the (non) finding of Alpba Centauri Bb was(n't) made. The gravity of the planet exerts a small pull on the star. This can be picked up by Doppler spectroscopy. That's why the very first exoplanets discovered, in the mid-nineties, were of 'Hot Jupiters'; they were massive planets, close to their star. Easier to notice with the instrumentation available then; big planet, short orbital period.
The thousands of discoveries by Kepler were by the transit method. If you have the proper viewing geometry, the planet will eclipse a tiny amount of light from the star as it passes between it and Earth.
As for 'glow'; no Earth sized planet is likely to be seen around any sort of star directly, with current instruments. The light from the star drowns out everything for many AU. And the planets only have a feeble light output from reflected light. We wouldn't see Earth from Proxima.
Solon
1 / 5 (2) Aug 20, 2016
There is no proof that Proxima is a star at all, not until we can see it as well as SOHO sees our own Sun.

TMcGrath
1 / 5 (1) Aug 23, 2016
It might be possible to reach Proxima Centauri and return in our lifetime, but it would require a craft capable of generating thrust for years at a time. Traveling 4.24 light years using 1G of continuous thrust (accelerating for half the distance, and decelerating for half the distance) would take 5 years, 10 months, and 13 days from Earth's perspective. Due to time dilation those on board the spacecraft would experience a trip taking 3 years, 6 months, and 15 days and reach a maximum speed of 95% the speed of light. Even using something like antimatter (and assuming the engines are 100% efficient) you could never bring enough fuel to reach the star, much less have enough for a round trip. Therefore, it would only be possible if fuel could be manufactured or collected along the way. For example, a hydrogen fusion ramjet that would collect hydrogen as it travels might be a possibility. At slower speeds less fuel would be required, but more time would be added to the trip.
TMcGrath
1 / 5 (1) Aug 23, 2016
It should also be noted that the Habitable Zone (Kopparapu et al. - 2014) around Proxima Centauri is only 6,432,708 km (3,997,100 miles) or 0.043 AU for the "conservative" inner Habitable Zone, and 12,715,819 km (7,901,244 miles) or 0.085 AU for the "conservative" outer Habitable Zone. By comparison Mercury's semi-major axis is 57,909,050 km (35,983,015 miles) or 0.387 AU from the Sun.

Proxima Centauri is also one of the most active flare stars known. Which does not bode well for any planet within its Habitable Zone.
Azrael
1 / 5 (1) Aug 25, 2016
A planet we could reach in our lifetime? Are you high or stupid? It would take thousands of years to reach it with today's technology.


Incorrect. Solar / laser light sails can be easily built with today's technology, and could reach an impressive fraction of the speed of light, if they don't fall apart from collisions with micro-meteorites, interstellar dust, and multi-million degree gas outside of the heliopause.

The scientific payload on such a craft would be severely limited by weight though.

High? No. Stupid? Depends on what/who you compare me to, relatively.

Either way, your comment is rather childish isn't it?

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