Proxima Centauri - Our Solar System's Nearest Neighbor to Be Closely Examined for Exoplanets

Canadian "Humble" Space Telescope to Begin Transit Observations Next Week



(Image: Photo of Proxima Centauri from the Hubble Space Telescope)

Nearby star Alpha Centauri B was found to have a planet last year. Now it's closer sibling Proxima will get a closer look for planets.


One common criticism of the nearly daily exoplanet discoveries from NASA's Kepler mission has been the distances of the stars these planets orbit.

Kepler's mission was one to gather statistics on the prevalence of different types of planets in our Milky Way, specifically the prevalence of other planets similar in size to our Earth.

In order to gather useful statistics Kepler stared at a patch of sky which included a representative sample of stars, kinda how TV ratings are compiled from representative populations in various markets.

Such statistics can then be applied to the Milky Way galaxy as a whole.

Unfortunately most of the planets around stars in the Kepler field lay hundreds of light-years away and are out of reach from closer scrutiny by the James Webb Space Telescope due to launch in 2018.

With Kepler's primary mission over, attention has now turned closer to home. Our nearby neighbors.

Finding planets around nearby stars whose atmosphere's can be sniffed by the James Webb Space Telescope is a top priority of many ground based hunts for exoplanets as well as NASA's TESS mission due to launch in 2017.

One star in particular, Proxima Centauri, just 4.3 light-years away is the nearest one to our sun and Solar System and it is about to get a closer look for planets thanks to a Canadian Space Telescope called MOST (and nicknamed the Humble Space Telescope).

From: Proxima Centauri Transit Search to Begin

Unlike Kepler or COROT, this telescope is functioning very well still, so many of us are very disappointed by this decision. The cost of running MOST each year is also relatively low, at just $450K per year. I believe Jaymie is looking for ways to slim that down in efforts to fund MOST privately or via a crowd-funding platform. [We’ll track this effort as it develops - expect more soon - PG].

MOST has discovered a great deal of exciting science both in terms of stellar astrophysics and exoplanet research. Perhaps its most famous discovery was the detection of transits of 55 Cancri e, the first naked eye star with a transiting planet (and I think still the only one!). This kind of high-risk high-gain science is perfect for MOST and nothing else really fills the gap right now. [You can read about MOST and 55 Cancri e in A Super-Earth in Transit (and a SETI Digression)].

Let me also tell you about a very exciting observing campaign for MOST from May 13th-May 28th which fits right into that category. In a 15-day continuous staring run, I am leading a campaign to observe Proxima Centauri in order to search for transits. This is the first transit survey of Proxima to date, as far as we are aware, which is quite extraordinary given it is the closest star.

Finding such a planet would be around Proxima would be a great thing for many scientific and non-scientific reasons as said in the excerpt below:

Just think about the possibilities of not only our nearest star having a planet but the unprecedented opportunities for following-up a bright, tiny M-dwarf hosting a transiting rocky planet(s). Any planet found would become everyone’s favorite overnight and JWST would be able to smell the atmosphere quite easily.

But the most compelling reason of all to look for a planet around Proxima is that such a world may provide the impetus needed to build the first interstellar space craft – we could fly there within our lifetimes and send back a photo.

If you need any more icing on the cake, a planet receiving the same insolation as the Earth around Proxima would have an orbital period of about 8.7 days and so our 15-day campaign should see a transit like that too.

Read more at the link I posted above. While this observing run only has a 10% chance of success it should be noted that Proxima Centauri is likely to be on the target list of NASA's Transiting Exoplanet Survey Satellite (TESS) mission which will look at all nearby stars for planet transits.

a reply to: JadeStar

Help me out if I'm too far off here. IIRC, it would take greater than 10,000 years to get there using technology at our disposal today. Puts 4.3 LYs into perspective.

I've always wished for the ones they find to be a bit closer.

Finding a possible Earth like planet that's 500 light years away, while we might be able to start turning our receivers towards it to see if they are broad casting, anything from us has not reached there yet (and will be of course so weak to be non-existent).

However, something that's only 10 light years away......we might even be able to communicate, if someone is there to listen and can broadcast back.

originally posted by: Snarl
a reply to: JadeStar

Help me out if I'm too far off here. IIRC, it would take greater than 10,000 years to get there using technology at our disposal today. Puts 4.3 LYs into perspective.

Actually, no. Try just under a hundred years.

Project Orion

Later studies indicate that the top cruise velocity that can theoretically be achieved by a Teller-Ulam thermonuclear unit powered Orion starship, assuming no fuel is saved for slowing back down, is about 8% to 10% of the speed of light (0.08-0.1c).[2] An atomic (fission) Orion can achieve perhaps 3%-5% of the speed of light. A nuclear pulse drive starship powered by Fusion-antimatter catalyzed nuclear pulse propulsion units would be similarly in the 10% range and pure Matter-antimatter annihilation rockets would be theoretically capable of obtaining a velocity between 50% to 80% of the speed of light. In each case saving fuel for slowing down halves the max. speed. The concept of using a magnetic sail to decelerate the spacecraft as it approaches its destination has been discussed as an alternative to using propellant, this would allow the ship to travel near the maximum theoretical velocity.[16]

At 0.1c, Orion thermonuclear starships would require a flight time of at least 44 years to reach Alpha Centauri, not counting time needed to reach that speed (about 36 days at constant acceleration of 1g or 9.8 m/s2). At 0.1c, an Orion starship would require 100 years to travel 10 light years. The astronomer Carl Sagan suggested that this would be an excellent use for current stockpiles of nuclear weapons.[17]

Not quite as fast as say Warp drive or something like that. But still, you're talking about being able to get there in a single generation.

a reply to: JadeStar
Wormhole. That's what we need to be able to travel to distant stars. We need to be able to open one, pinpoint it's exit, and keep it open long enough to travel through.

That's just in our 4 dimensions. If we ever find a way to utilize other dimensions it might become a simpler process.

a reply to: JadeStar

Now that should be interesting, at 4.35 LY approx it is a red dwarf which may have small rocky planet's, it would be a real eye opener if they actually discover one, I wonder if that star is from the same stella nursery our sun is from or if it could be a lot older.
Often overlooked in favour of it's neighbour's alpha and beta it is very interesting nonetheless and maybe the star that humans or at least our machines are most likely to visit one day if we ever get out that far.
Being a red dwarf though if it formed in the same stella nursery then that means it had less mass density to that part of the nebulae and so a lower probability of planetary formation on a large scale which does not rule out the possible existance of at least a few large asteroid or even moon and maybe earth mass body's but what density will they have.
I look forward to the data they may gather though it takes years to see if there is a transiting body unless it is very close to the star.

originally posted by: Snarl
a reply to: JadeStar

Help me out if I'm too far off here. IIRC, it would take greater than 10,000 years to get there using technology at our disposal today. Puts 4.3 LYs into perspective.

It depends what you mean by technology at our disposal today.

By chemical rocket like the Voyager probes you are correct.

However there is are several other types of propulsion available today which if thoroughly funded and developed could in fact send a ship there within a human lifetime.

An interstellar probe is not so much a technological/engineering issue as a funding issue.

It would not be cheap, nor would it be the sort of instantaneous trips offered by sci-fi warp drives and the like but we could probably get something up to 10-20% the speed of light which would get us there in 20-40 years.

originally posted by: eriktheawful

originally posted by: Snarl
a reply to: JadeStar

Help me out if I'm too far off here. IIRC, it would take greater than 10,000 years to get there using technology at our disposal today. Puts 4.3 LYs into perspective.

Actually, no. Try just under a hundred years.

Project Orion

Yes.

There's also the Project Icarus design study which builds on the old work by the British Interplanetary Society Project Daedalus effectively updating it.

a reply to: JadeStar

Oh wow never knew we can do this, Iam so proud of humanity sometimes.
Better pack a bag then eh? still got 20 years in me so I will go .

a reply to: JadeStar

From what I can see in the article, they will use the transit method for searching for small rocky planets. The article mentions that the radial velocity method (where we look for the "wobble" of star that an orbiting planet may cause) is not yet sensitive enough to detect small rocky planets, and planets around stars such as Proxima Centauri will probably be small. So the transit method makes sense here.

However, the transit method relies on a planet actually transiting (passing directly in front of) its star from the viewpoint of Earth. If a planet doesn't transit, then it can't be found using the transit method. Therefore, even if this search finds no planets, that is NOT an indication the Proxima Centauri has no planets -- it could simply be that the ecliptic plane of Proxima Centauri is tilted relative to us in such a way that we will not see those planets transiting.

So while a positive outcome of this search would be exciting, a negative outcome would STILL not yet answer the question as to whether or not Proxima Centauri has planets. Even if the find nothing, that doesn't mean the planets are not there; it would simply mean none of them transited between us and the star.

originally posted by: LABTECH767
a reply to: JadeStar

Now that should be interesting, at 4.35 LY approx it is a red dwarf which may have small rocky planet's, it would be a real eye opener if they actually discover one, I wonder if that star is from the same stella nursery our sun is from or if it could be a lot older.

There's been a bit of work done on whether Proxima and Alpha Centauri A and B formed from the same stellar nursery as our Sun. It seems doubtful that they were.

Often overlooked in favour of it's neighbour's alpha and beta it is very interesting nonetheless and maybe the star that humans or at least our machines are most likely to visit one day if we ever get out that far.

Alpha Centauri B is not Beta Centauri.

Beta Centauri is an entirely different star 450 light years away (100 time further than Alpha Centauri A and B). Common mistake and one which even the US Naval Academy made in their Project Longshot.

SEE: Project Longshot: An Unmanned Probe To Alpha Centauri - US Naval Academy (full text)

Being a red dwarf though if it formed in the same stella nursery then that means it had less mass density to that part of the nebulae and so a lower probability of planetary formation on a large scale which does not rule out the possible existance of at least a few large asteroid or even moon and maybe earth mass body's but what density will they have.

Well we know that red dwarfs produce planets at the same rate other more massive stars do, thanks to Kepler. They just produce smaller ones compared to their larger sisters. So while it is unlikely there is a massive Jupiter sized world around Proxima, there could be several Super Earth, Earth, Mars size and below planets.

I look forward to the data they may gather though it takes years to see if there is a transiting body unless it is very close to the star.

I think you're thinking of radial velocity searches where that statement is true. Transits for low mass planets close to small star like Proxima can take place over hours or days. In fact a planet in the habitable zone if we were lined up with the plane of its orbit nicely would produce a couple of transits lasting less than the 15 day observing run as explained here

If you need any more icing on the cake, a planet receiving the same insolation as the Earth around Proxima would have an orbital period of about 8.7 days and so our 15-day campaign should see a transit like that too. -

originally posted by: Soylent Green Is People
a reply to: JadeStar

However, the transit method relies on a planet actually transiting (passing directly in front of) its star from the viewpoint of Earth. If a planet doesn't transit, then it can't be found using the transit method. Therefore, even if this search finds no planets, that is NOT an indication the Proxima Centauri has no planets -- it could simply be that the ecliptic plane of Proxima Centauri is tilted relative to us in such a way that we will not see those planets transiting.

So while a positive outcome of this search would be exciting, a negative outcome would STILL not yet answer the question as to whether or not Proxima Centauri has planets. Even if the find nothing, that doesn't mean the planets are not there; it would simply mean none of them transited between us and the star.

Exactly.

Cross fingers and hope the planets transit but if they don't we still learn something new about any potential planets around Proxima in that we can restrict the plane they orbit Proxima in with regards to our solar system.

Which will greatly help future direct imaging missions like perhaps a revamped Terrestrial Planet Finder or New World Observer.

originally posted by: JadeStar
However there is are several other types of propulsion available today which if thoroughly funded and developed could in fact send a ship there within a human lifetime.

An interstellar probe is not so much a technological/engineering issue as a funding issue.

It would not be cheap, nor would it be the sort of instantaneous trips offered by sci-fi warp drives and the like but we could probably get something up to 10-20% the speed of light which would get us there in 20-40 years.

If you are travelling at a significant fraction of c, wouldn't an impact with even a tiny bit of space debris be rather catastrophic?

If a tiny fleck of paint can do this to a window of the Space Shuttle, travelling at a relative snail's pace:

then how will interstellar craft have to be shielded?

Yes, since the energy of an impact is proportional to its velocity, the effect of a given piece of debris could be over 3700 times greater at 0.1 the speed of light, than at Earth orbital velocity.

a reply to: eriktheawful

Let's assume they were able to use the mater/anti-matter rockets to get to 80% the speed of light. . .

Years to the observer would be weeks and months to the occupants of the space ship.

I've been reading way to much Orson Scott Card "Ender's Saga" books ...

originally posted by: Rob48

originally posted by: JadeStar
However there is are several other types of propulsion available today which if thoroughly funded and developed could in fact send a ship there within a human lifetime.

An interstellar probe is not so much a technological/engineering issue as a funding issue.

It would not be cheap, nor would it be the sort of instantaneous trips offered by sci-fi warp drives and the like but we could probably get something up to 10-20% the speed of light which would get us there in 20-40 years.

If you are travelling at a significant fraction of c, wouldn't an impact with even a tiny bit of space debris be rather catastrophic?

If a tiny fleck of paint can do this to a window of the Space Shuttle, travelling at a relative snail's pace:

then how will interstellar craft have to be shielded?

Correct.

There are two or three ways. One has to decide whether they want to deflect, destroy or absorb such particles. There are ways to do one or all three through things like lasers, magnetic fields/plasma, ablation shields, etc.

From a post at Centauri Dreams

It would be helpful if space were a bit more empty. A key problem facing an interstellar probe would be encounters with dust in the planetary system it leaves and, as it reaches cruising speed, dust impact in space between the stars. Although our Solar System seems to be in an unusually sparse pocket of space, the galaxy-wide distribution of hydrogen is roughly one atom per cubic centimeter. Dust — bits of carbon, ice, iron compounds, and silicates — is far rarer still, but enough of a factor to a ship moving at a significant fraction of the speed of light that the designers of the Project Daedalus craft built in a payload shield 32-meters in radius to protect their starship.

Collision with interstellar dust becomes a major issue when you’re traveling at speeds like these, a fact Andrews is quick to quantify. For a starship moving at 0.3 c, a typical grain of carbonaceous dust about a tenth of a micron in diameter should have a relative kinetic energy of 37,500,000 GeV. Our hypothetical star mission with human crew moving at a substantial fraction of light speed will run into about thirteen of these dust particles every second over every square meter of frontal area.

Back to Daedalus, which was designed to move at 12 percent of lightspeed for the fifty year journey to Barnard’s Star. Along with its beryllium shield for the cruise phase, Daedalus would have needed additional protection for the stellar encounter, which designer Alan Bond suggested could take the form of a cloud of dust deployed from the main vehicle, heating and vaporizing any larger particles before they could damage the payload. And because Daedalus would deploy smaller probes within the system, each would need a cloud of its own.

Gregory Matloff and Eugene Mallove once suggested that a starship could use, in addition to a shield, a high-powered beamed energy device to destroy or deflect any larger objects in its path. So the options for interstellar protection are slowly being placed on the table. But first we have to learn more about the nature of the problem, which means studies like these that tell us how dust forms in the first place.

Really? You'd think that's where they woulda STARTED looking.

Where do I get my scientist card?

originally posted by: ScientiaFortisDefendit
Really? You'd think that's where they woulda STARTED looking.

Well to be fair they did. As far back as the 1980s in fact.

It is only in recent years that technology has allowed us to examine the nearest bright stars for transits. They are very, VERY difficult to detect as outlined here:

Where do I get my scientist card?

You can print one out if you take part in many of these citizen science programs

Proxima Centauri is rather young, as red dwarf stars go; only about 4 billion, 850 million years old. Like other young red dwarfs it has large flares, markedly increasing its brightness at times. Perhaps not the most promising place for a life-bearing planet. Unless such a planet had a strong magnetic field to protect it, it might eventually have its atmosphere blasted away by these flares. The surface temperature would probably swing rather violently, too.
A habitable planet of such a star would presumably be tidally locked, always presenting the same face to its star. That might not be the problem it was once thought to be, provided the planet has a thick atmosphere, capable of circulating heat from the light to the dark side, evening out the extremes of heat and cold.
We can only conjecture at the moment that a planet with a spin as slow as 8 & 1/2 days might still be able to maintain the necessary magnetic field, or that an atmosphere of sufficient thickness and strong enough circulation could exist, and persist.

if i remember correctly chances are that nearly all stars or their planetary disks align in nearly the same plane because it is the most energy conserving to do so. for those stars that tilt a lot there has to have been some precipitating event that caused the abberration from the norm? if i have that right chances are any planets that formed naturally around that star as opposed to captured orphans or cataclysmically perturbed ones will orbit in more or less the same plane as earth. there will be some variation and it is true that that variation could place a planet out of favorable alignment for transit observation but there should be a better probability that some sort of transit should be observable. particularly when you consider that planets orbit red dwarfs much nearer than planets around other types of stars. the life zone for such stars is well within mercury's orbital distance from our own sun. and the gravity of such stars is much much weaker than that of a g or k type star. so if you orbit well out... well you usually don't. planets that far out normally get booted or pulled out of the orbital mechanics club i think.

as to actual travel by probe or manned mission once we have technology of 100 year or less those become more and more attractive. remember that voyager is going strong at 37 or so years. we could do a probe at least with one of several near term technologies that can be expected to be feasible soon.