. 24/7 Space News .
EXO WORLDS
Could Proxima Centauri b Really Be Habitable
by Staff Writers
Seattle WA (SPX) Aug 31, 2016


Artist's impression of the planet orbiting the red dwarf star Proxima Centauri. Image courtesy ESO

The world's attention is now on Proxima Centauri b, a possibly Earth-like planet orbiting the closest star, 4.22 light-years away. The planet's orbit is just right to allow liquid water on its surface, needed for life. But could it in fact be habitable?

If life is possible there, the planet evolved very different than Earth, say researchers at the University of Washington-based Virtual Planetary Laboratory (VPL) where astronomers, geophysicists, climatologists, evolutionary biologists and others team to study how distant planets might host life.

Astronomers at Queen Mary University in London have announced discovery of Proxima Centauri b, a planet orbiting close to a star 4.22 light-years away. The find has been called "the biggest exoplanet discovery since the discovery of exoplanets."

Rory Barnes, UW research assistant professor of astronomy, published a discussion about the discovery at palereddot.org, a website dedicated to the search for life around Proxima Centauri. His essay describes research under way through the UW planetary lab - part of the NASA Astrobiology Institute - to answer the question, is life possible on this world?

"The short answer is, it's complicated," Barnes writes. "Our observations are few, and what we do know allows for a dizzying array of possibilities" - and almost as many questions.

The Virtual Planetary Laboratory is directed by Victoria Meadows, UW professor of astronomy. UW-affiliated researchers include Giada Arney, Edward Schwieterman and Rodrigo Luger. Using computer models, the researchers studied clues from the orbits of the planet, its system, its host star and apparent companion stars Alpha Centauri A and B - plus what is known of stellar evolution to begin evaluating Proxima b's chances.

Relatively little is known about Proxima:

* It's at least as massive as Earth and may be several times more massive, and its "year" - the time it takes to orbit its star - is only 11 days.

* Its star is only 12 percent as massive as our Sun and much dimmer (so its habitable zone, allowing liquid water on the surface, is much closer in) and the planet is 25 times closer in than Earth is to our Sun.

* The star may form a third part of the Alpha Centauri binary star system, separated by a distance of 15,000 "astronomical units," which could affect the planet's orbit and history.

* The new data hint at the existence of a second planet in the system with an orbital period near 200 days, but this has not been proven.

Perhaps the biggest obstacle to life on the planet, Barnes writes, is the brightness of its host star. Proxima Centauri, a red dwarf star, is comparatively dim, but wasn't always so.

"Proxima's brightness evolution has been slow and complicated," Barnes writes. "Stellar evolution models all predict that for the first one billion years Proxima slowly dimmed to its current brightness, which implies that for about the first quarter of a billion years, planet b's surface would have been too hot for Earth-like conditions."

Barnes notes that he and UW graduate student Rodrigo Luger recently showed that had modern Earth been in such a situation, "it would have become a Venus-like world, in a runaway greenhouse state that can destroy all of the planet's primordial water," thus extinguishing any chance for life.

Next come a host of questions about the planet's makeup, location and history, and the team's work toward discerning answers.

* Is the planet "rocky" like Earth? Most orbits simulated by the planetary lab suggest it could be - and thus can host water in liquid form, a prerequisite for life.

* Where did it form, and was there water? Whether it formed in place or farther from its star, where ice is more likely, VPL researchers believe it is "entirely possible" Proxima b could be water-rich, though they are not certain.

* Did it start out as a hydrogen-enveloped Neptune-like planet and then lose its hydrogen to become Earth-like? VPL research shows this is indeed possible, and could be a viable pathway to habitability.

* Proxima Centauri flares more often than our Sun; might such flares have long-since burned away atmospheric ozone that might protect the surface and any life? This is possible, though a strong magnetic field, as Earth has, could protect the surface. Also, any life under even a few meters of liquid water would be protected from radiation.

Another concern is that the planet might be tidally locked, meaning one side permanently faces its star, as the Moon does Earth. Astronomers long thought this to mean a world could not support life, but now believe planetwide atmospheric winds would transport heat around the planet.

"These questions are central to unlocking Proxima's potential habitability and determining if our nearest galactic neighbor is an inhospitable wasteland, an inhabited planet, or a future home for humanity," Barnes writes.

Planetary laboratory researchers also are developing techniques to determine whether Proxima b's atmosphere is amenable to life.

"Nearly all the components of an atmosphere imprint their presence in a spectrum (of light)," Barnes writes. "So with our knowledge of the possible histories of this planet, we can begin to develop instruments and plan observations that pinpoint the critical differences."

At high enough pressures, he notes, oxygen molecules can momentarily bind to each other to produce an observable feature in the light spectrum.

"Crucially, the pressures required to be detectable are large enough to discriminate between a planet with too much oxygen, and one with just the right amount for life.

As we learn more about the planet and the system, we can build a library of possible spectra from which to quantitatively determine how likely it is that life exists on planet b."

Our own Sun is expected to burn out in about 4 billion years, but Proxima Centauri has a much better forecast, perhaps burning for 4 trillion years longer.

"If Proxima b is habitable, then it might be an ideal place to move. Perhaps we have just discovered a future home for humanity. But in order to know for sure, we must make more observations, run many more computer simulations and, hopefully, send probes to perform the first direct reconnaissance of an exoplanet," Barnes writes. "The challenges are huge, but Proxima b offers a bounty of possibilities that fills me with wonder."

Proxima Centauri b may be the first exoplanet to be directly characterized by powerful ground- and space-based telescopes planned for the future, and its atmosphere spectroscopically probed for active biology.

"Whether habitable or not," Barnes concludes, "Proxima Centauri b offers a new glimpse into how the planets and life fit into our universe."


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
University Of Washington
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
EXO WORLDS
Rocky planet found orbiting habitable zone of nearest star
Washington DC (SPX) Aug 25, 2016
An international team of astronomers including Carnegie's Paul Butler has found clear evidence of a planet orbiting Proxima Centauri, the closest star to our Solar System. The new world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface, if it were present. This rocky world is a little more massive th ... read more


EXO WORLDS
Space tourists eye $150mln Soyuz lunar flyby

Roscosmos to spend $7.5Mln studying issues of manned lunar missions

Lockheed Martin, NASA Ink Deal for SkyFire Infrared Lunar Discovery Satellite

As dry as the moon

EXO WORLDS
Anomalous grooves on Martian moon Phobos explained by impacts

NASA Approves 2018 Launch of Mars InSight Mission

Storm Reduces Available Solar Energy on Opportunity

Test for damp ground at Mars' seasonal streaks finds none

EXO WORLDS
The Deep Space Network

At Berlin tech fair, waterproof gadgets make a splash

Grandpa astronaut breaks US space record

35 years later Voyager's legacy continues at Saturn

EXO WORLDS
Tiangong 2 is coming soon, real soon

China's newly-launched quantum communication satellite in good shape

China Sends Country's Largest Carrier Rocket to Launch Base

'Heavenly Palace': China to Launch Two Manned Space Missions This Fall

EXO WORLDS
US astronauts complete spacewalk for ISS maintenance

Space Station's orbit adjusted Wednesday

Astronauts Relaxing Before Pair of Spaceships Leave

'New port of call' installed at space station

EXO WORLDS
Vega's multi-satellite payload integration begins for Arianespace Flight VV07

Launch pad blast destroys SpaceX rocket, Facebook satellite

India To Launch 5 Satellites In September

Sky Muster II comes to French Guiana for launch on Ariane 5

EXO WORLDS
Discovery one-ups Tatooine, finds twin stars hosting three giant exoplanets

New light on the complex nature of 'hot Jupiter' atmospheres

Could Proxima Centauri b Really Be Habitable

Rocky planet found orbiting habitable zone of nearest star

EXO WORLDS
3D skulls from Henry VIII's doomed warship placed online

Mega tech fair IFA dives head-first into virtual reality

New plastic clothing material could keep people cool

Northrop Grumman gets $375 million G/ATOR radar contract









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.