Astronomers Discover a New Planet Orbiting the Closest Star to the Sun!

There’s no other way to phrase it. This is HUGE news: Astronomers have found a planet orbiting the Proxima Centauri, the closest star to the Sun!

Holy wow. Seriously. Wow.

Before I get into details, let me sum up what we know:

The planet, called Proxima Centauri b or just Proxima b (exoplanets are given their star’s name plus a lower case letter in order of discovery, starting with “b”), orbits Proxima every 11.2 days. It has a mass of no less than 1.3 times the Earth’s, so if it’s rock and metal like Earth it’s only a bit bigger. It’s a mere 7.3 million kilometers from the star—a lot closer than Earth’s distance from the Sun of 150 million kilometers!—but Proxima is so faint and cool it receives about two-thirds the amount of light and heat the Earth does. That means that it’s in Proxima’s habitable zone: It’s possible (more or less) that liquid water could exist on its surface.

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Pretty darn cool huh. :)

Yep, pretty darn cool.

:)

Planets, planets everywhere!

Michael V said:

Yep, pretty darn cool.

:)

When are Astronomers going to start calling them ‘Class M’ planets? That would be way cooler.

Rule 303 said:

Michael V said:

Yep, pretty darn cool.

:)

When are Astronomers going to start calling them ‘Class M’ planets? That would be way cooler.

explain

dv said:

explain

Star Trek designation for planets suitable for Human habitation.

‘Class M’ planets? I don’t get it.

Rule 303 said:

dv said:

explain

Star Trek designation for planets suitable for Human habitation.

NERRRRRRRRRRRRRRRRRRRD

dv said:

NERRRRRRRRRRRRRRRRRRRD

You seem troubled….

dv said:

Rule 303 said:

dv said:

explain

Star Trek designation for planets suitable for Human habitation.

NERRRRRRRRRRRRRRRRRRRD

LOL

“Proxima Centauri is a red dwarf star (a star with a lower mass than our sun) located four light-years from the solar system.”

I take it our sun is a red dwarf.

Peak Warming Man said:

“Proxima Centauri is a red dwarf star (a star with a lower mass than our sun) located four light-years from the solar system.”

I take it our sun is a red dwarf.

Ummm, no.

Peak Warming Man said:

“Proxima Centauri is a red dwarf star (a star with a lower mass than our sun) located four light-years from the solar system.”

I take it our sun is a red dwarf.

?

Anyone like to tell me why this is such a big deal?

Because it’s on our doorstep? AFAIK it’s the closest known planet to our solar system, which makes things exciting should we develop technology to travel interstellar distances.

dv said:

Rule 303 said:

dv said:

explain

Star Trek designation for planets suitable for Human habitation.

NERRRRRRRRRRRRRRRRRRRD

It’s more disgraceful you didn’t know that

The Rev Dodgson said:

Anyone like to tell me why this is such a big deal?

Huh? At near the speed of light we could get there in negligible real time because of Lorentz contraction. No wormholes necessary.

Also, as the eighth nearest planet it’s a really big deal. (Did you notice I said eighth? Count them.) The faintness of the light from Proxima should make it extremely easy to determine its atmosphere, gravity, etc.

I haven’t read the link yet, but am still waiting to know whether there’s a planet or two around Alpha Centauri. There was a tentative detection in 2012. “The exoplanet next door: Earth-sized world discovered in nearby α Centauri star system”. Eric Hand, Nature, October 16, 2012. And not a whisper about it since.

mollwollfumble said:

The Rev Dodgson said:

Anyone like to tell me why this is such a big deal?

Huh? At near the speed of light we could get there in negligible real time because of Lorentz contraction. No wormholes necessary.

Also, as the eighth nearest planet it’s a really big deal. (Did you notice I said eighth? Count them.) The faintness of the light from Proxima should make it extremely easy to determine its atmosphere, gravity, etc.

I haven’t read the link yet, but am still waiting to know whether there’s a planet or two around Alpha Centauri. There was a tentative detection in 2012. “The exoplanet next door: Earth-sized world discovered in nearby α Centauri star system”. Eric Hand, Nature, October 16, 2012. And not a whisper about it since.

Being next door so to speak should make observation easier than something hundreds of light years away

It also makes it really likely that aliens are visiting from that system…

*runs away *

Rule 303 said:

Michael V said:

Yep, pretty darn cool.

:)

When are Astronomers going to start calling them ‘Class M’ planets? That would be way cooler. Star Trek

Actually, they better not.

“Class M” in astronomy is a red dwarf or brown dwarf. Proxima Centauri itself is a “Class M”, to be specific a “Class M6”, and I wouldn’t want to try landing on that.

The sequence as you cool off is “Class M”, “Class L”, “Class T”, “Class Y” with subclasses from 0 to 9.9. To me, “Class Y1” and “Class Y2” screams “Earthlike planet”.

Divine Angel said:

It also makes it really likely that aliens are visiting from that system…

*runs away *

chases

On the radio it said if we use today’s technology we could reach it in around 800,000 years. So we might need a worm hole or two to go see.

That seems a bit pessimistic. We could, using today’s technology, send a probe to Prox Cent that would arrive in a few tens of thousands of years.

Of course, it wouldn’t be functional, and we wouldn’t be able to receive its signal, and human civilisation would have decayed. But 800000 is over the top.

dv said:

That seems a bit pessimistic. We could, using today’s technology, send a probe to Prox Cent that would arrive in a few tens of thousands of years.

Of course, it wouldn’t be functional, and we wouldn’t be able to receive its signal, and human civilisation would have decayed. But 800000 is over the top.

Well whatever it is, you would definitely need a packed lunch.

PermeateFree said:

On the radio it said if we use today’s technology we could reach it in around 800,000 years. So we might need a worm hole or two to go see.

No.

That 800,000 years is about right, with nuclear fusion that could perhaps be cut to about 40,000. That’s not an excessively long time for a robotic or seedship. And technology better than fusion power may be just around the corner.

With wormhole technology it would require at least 4,000,000,000 years. That’s how long it would take to get to the mouth of the nearest big wormhole and back. Small wormholes are useless for travel. Only feasible for intergalactic and inter-universe travel.

mollwollfumble said:

PermeateFree said:

On the radio it said if we use today’s technology we could reach it in around 800,000 years. So we might need a worm hole or two to go see.

No.

That 800,000 years is about right, with nuclear fusion that could perhaps be cut to about 40,000. That’s not an excessively long time for a robotic or seedship. And technology better than fusion power may be just around the corner.

With wormhole technology it would require at least 4,000,000,000 years. That’s how long it would take to get to the mouth of the nearest big wormhole and back. Small wormholes are useless for travel. Only feasible for intergalactic and inter-universe travel.

I thought the Project Orion class ships could do it in about 44 years

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.

Looking up original technical article now.

http://www.nature.com/nature/journal/v536/n7617/full/nature19106.html

The“year” of this planet is only 11.2 days.

Proxima Centauri, like most M stars, is a flare star. That means it has massively huge solar flares. Put a massive solar flare next to a planet that is 20 times as close to it’s parent star as the Earth is to the Sun and see what happens.

Planet found by Doppler variations in Proxima’s spectrum. I was hoping it would be.

The next question is whether the orbit is circular or not. From Figure 2, the orbit may not be completely circular, but isn’t a long way from circular. I’d have to do a calculation to be sure, but it looks like the eccentricity is less than 0.2. (Pluto’s is 0.25, Mercury’s is 0.21).

Next step would be to try to photograph it in IR using the VLTI, at a time when it is calculated to have greatest angular separation from the star.

mollwollfumble said:

Proxima Centauri, like most M stars, is a flare star. That means it has massively huge solar flares. Put a massive solar flare next to a planet that is 20 times as close to it’s parent star as the Earth is to the Sun and see what happens.

what would happen, do you think?

party_pants said:

mollwollfumble said:

Proxima Centauri, like most M stars, is a flare star. That means it has massively huge solar flares. Put a massive solar flare next to a planet that is 20 times as close to it’s parent star as the Earth is to the Sun and see what happens.

what would happen, do you think?

You’d need lot’s of tin-foil hats.

Cymek said:

I thought the Project Orion class ships could do it in about 44 years

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.

Yep.
Though if they used an autonomous spacecraft they could up the acceleration rate somewhat, and trade living quarters/support systems for humans/etc for more ‘fuel’, and so have a higher cruise speed as well. I can’t see why we couldn’t get a probe there in 10 – 20 years.

Michael V said:

Peak Warming Man said:

“Proxima Centauri is a red dwarf star (a star with a lower mass than our sun) located four light-years from the solar system.”

I take it our sun is a red dwarf.

Ummm, no.

Yes, no.

… but …. much to my annoyance …

every star on the main sequence, including our Sun, is called by astronomers a “dwarf”. So our Sun is officially a “yellow dwarf”.

The official size sequence of stars from largest to smallest is:

Supergiant
Giant
Singing
Dwarf
Subdwarf
White dwarf
Neutron star

mollwollfumble said:

Michael V said:

Peak Warming Man said:

“Proxima Centauri is a red dwarf star (a star with a lower mass than our sun) located four light-years from the solar system.”

I take it our sun is a red dwarf.

Ummm, no.

Yes, no.

… but …. much to my annoyance …

every star on the main sequence, including our Sun, is called by astronomers a “dwarf”. So our Sun is officially a “yellow dwarf”.

The official size sequence of stars from largest to smallest is:

Supergiant
Giant
Singing
Dwarf
Subdwarf
White dwarf
Neutron star

Singing?

Giants are normally followed by Subgiants. Our star is a main sequence G2 dwarf for which we should be thankful. The much larger ones tend to be one-hit wonders :)

Red dwarfs are thought to be the most common type of star and are particularly long-lived (trillions of years) which might well make them a good candidate for life-sustainers of planets in an appropriately close orbit.

> I take it our sun is a red dwarf

> Our Sun is officially a “yellow dwarf”.

Darn blasted spellchecker. It took me three goes to stop it from changing “subdwarf” to “windward”. After that it still autochanged “subgiant” to “singing”.

Supergiant
Giant
Subgiant
Dwarf
Subdwarf
White dwarf
Neutron star

mollwollfumble said:

> I take it our sun is a red dwarf

> Our Sun is officially a “yellow dwarf”.

Darn blasted spellchecker. It took me three goes to stop it from changing “subdwarf” to “windward”. After that it still autochanged “subgiant” to “singing”.

Supergiant
Giant
Subgiant
Dwarf
Subdwarf
White dwarf
Neutron star

That alarmed me somewhat!

i suppose the next logical step is to send a series of defensive nuclear devices

it worries me when i hear there are places that we can reach that may harbour life

wookiemeister said:

i suppose the next logical step is to send a series of defensive nuclear devices

it worries me when i hear there are places that we can reach that may harbour life

(Warning: cynic in residence)

Not at all, we need food for when we get there. There’s no point in landing on, for example a Marslike planet where there’s nothing to eat.

My calcs are still showing that the probability of intelligent life in the universe is indistinguishable from zero.

mollwollfumble said:

wookiemeister said:

i suppose the next logical step is to send a series of defensive nuclear devices

it worries me when i hear there are places that we can reach that may harbour life

(Warning: cynic in residence)

Not at all, we need food for when we get there. There’s no point in landing on, for example a Marslike planet where there’s nothing to eat.

My calcs are still showing that the probability of intelligent life in the universe is indistinguishable from zero.

That can only be near universe can’t it?

I just realised that the planet was found by a group calling itself the “Pale Red Dot” consortium.
Talking about Proxima as a pale red dot in analogy with Earth as a pale blue dot.
https://palereddot.org
There is also a Facebook and Twitter site for the group.

Pale Red Dot Is an outreach project to show to the public how scientists are working to address a major question that could affect us all, namely are there Earth-like planets around the nearest stars.

“After the campaign is finished by April 1st …”
Not the best date to choose.

The below graph shows Proxima Centauri as a flare star. Flares are marked.

mollwollfumble said:

I just realised that the planet was found by a group calling itself the “Pale Red Dot” consortium.
Talking about Proxima as a pale red dot in analogy with Earth as a pale blue dot.
https://palereddot.org
There is also a Facebook and Twitter site for the group.

Pale Red Dot Is an outreach project to show to the public how scientists are working to address a major question that could affect us all, namely are there Earth-like planets around the nearest stars.

“After the campaign is finished by April 1st …”
Not the best date to choose.

The below graph shows Proxima Centauri as a flare star. Flares are marked.

Maybe it would be warm enough for silicate based life?

There are other interesting websites related to this.

https://palereddot.org/terrestrial-planets-over-the-next-decade/

The following projects for finding exoplants are already funded.

mollwollfumble said:

There are other interesting websites related to this.

https://palereddot.org/terrestrial-planets-over-the-next-decade/

The following projects for finding exoplants are already funded.

https://palereddot.org/wp-content/uploads/2016/03/Figure2-TransitRoadmap.png

Why isn’t CoRoT on that figure? CoRoT can find exoplanets just like Kepler, and has indeed done so. It’s just a bit smaller and slower.