Traveling outward from the Earth into interstellar space to our nearest neighbors, so far we’ve encountered 3 star systems--Alpha Centauri (Part 1), and Barnard’s Star and Luhman 16ab (Part 2).

Let’s continue our journey outward from our solar system with the next three stops!

WISE 0855-0714 (sub-brown dwarf? planet?--7.2 light years away)

Generally southeast towards our galactic center (and upwards a bit in three dimensions) is WISE 0855-0714 (let’s just call it 714 from here on out).

714 is a very odd character! Discovered in April 2014 using NASA’s Wide-field Infrared Survey Explorer (WISE) satellite (the same satellite that discovered Luhman 16ab), 714 is only about 3 to 10 times as massive as Jupiter. It is variously termed a sub-brown dwarf or a planet--although according to our definition of anything under 13 masses of Jupiter being a planet, that’s probably as good a term as any.

There is some argument on that. 714 may have fused deuterium in the distant past--the 13 Jupiter mass cut-off is something of a guess, so it is possible that less massive dwarfs could have fused some deuterium. Also, some astronomers only consider planets to be bodies orbiting another star, and any “planet”-sized body on its own as a sub-brown dwarf. It’s mostly semantics.

714 may be up to 10 billion years old--more than twice the age of our solar system--so if there was any fusing of deuterium, it would have ended long ago. In fact, even larger brown dwarfs fuse all their deuterium about 10 million years after forming, and they just remain hot and glowing for hundreds of millions to billions of years afterwards.

The gist of 714 is that now its surface is only -55 to +8 degrees Fahrenheit! That’s a lot warmer than deep space, but it makes 714 the coldest body we’ve found outside our solar system. In August 2014, astronomers used one of the large telescopes in Chile to discover that 714 is about half shrouded in water ice clouds--the first detection of water ice clouds outside our solar system!

Do we want to point our spacecraft towards 714? Water ice is a draw to be sure. But almost no light or energy would be provided from the planet/sub-brown dwarf. No other planets have been detected orbiting it at this point. It would be a 36 year journey at 20% the speed of light.

Let’s check out the next stop!

Wolf 359 (red dwarf--7.8 light years away)

Finally, back to a real star!

A very dim and old red dwarf, Wolf 359 is almost due west from our Sun (and fairly far upwards in 3 dimensions) if our galactic center is to the southeast. It may be more than 10 billion years old, and is about 15%-20% the diameter of our Sun and about 9% of the Sun’s mass. For comparison, 8% of the Sun’s mass is where fusion of normal hydrogen can take place. So, Wolf 359 just barely made it to being a star.

Wolf 359 is a flare star, like most red dwarfs; however, its flares are very weak and not that frequent compared to, say, Proxima Centauri. Again, its age is showing!

After intense searching, no planets have been found around Wolf 359.

Interestingly though, Wolf 359 has had a role in a number of science fiction shows. It shows up in a 1964 Outer Limits television show where a scientist on Earth creates a miniature version of a planet in the Wolf 359 system; and it is also the scene of a large battle in Star Trek: The Next Generation where the Borg assimilates Captain Picard and the Deep Space Nine pilot episode.

Should we point our spacecraft there? There doesn’t seem much reason to spend 39 years (at 20% the speed of light) to go there.

Onwards!

Lalande 21185 (red dwarf--8.3 light years away)

Another red dwarf, Lalande 21185 (also known as Gliese 411), is the next-distant star system within our 10 light year range. Lalande would be about northwest from us (and very high upwards in 3 dimensions) assuming our galactic center is to the southeast. At 20% light speed, it would take our spacecraft about 41-42 years to reach the system.

Lalande is a fairly large red dwarf--about 40% diameter of our Sun, and 50% of the Sun’s mass. This makes it more interesting as a potential place with planets that could support life. But, as with most red dwarfs, Lalande is a flare star, meaning any planets existing within its habitable zone are likely to get bathed in a ton of x-ray radiation. Not very conducive for life as we know it.

Are there planets around Lalande. We’re not 100% sure yet. An early claim in 1996 could not be confirmed. Some follow-up studies seem to show that something is making the star wobble a bit. Perhaps 3 planets--all large and all unconfirmed, are suspected. One, about twice the distance the Earth is from the Sun, about the size of Jupiter. One, 11 time the distance the Earth is from the Sun, nearly twice the size of Jupiter. And perhaps one way beyond 11 AUs, about the size of Jupiter. If any or all of these are confirmed, they would all be gas giants.

Water signatures have been detected from the Lalande system. Astronomers are not sure if this is from the star itself (doubtful) or some planet(s) in the system. Also, spectral readings from Lalande show only about half the metal content of the Sun, so any planets around the star would likely have only about half the metals (e.g., iron) that the Earth has.

Lalande 21185 is also referred to in fiction quite often, taking a prominent role in 8 novels and 4 computer games.

Summary

So, not too much potential in these three stops. Lalande 21185 seems the best bet, with indications of water and possibly many planets.

There are only 3 systems left to visit within 10 light years! The topic of the next Science Escape! We'll start with something of a surprise!

Sources:

http://solstation.com/stars/wise1049.htm

http://solstation.com/stars/wise0855.htm

https://en.wikipedia.org/wiki/WISE_0855−0714

http://solstation.com/stars/wolf359.htm

https://en.wikipedia.org/wiki/Wolf_359

https://en.wikipedia.org/wiki/Wolf_359_(The_Outer_Limits)

https://en.wikipedia.org/wiki/Battle_of_Wolf_359

http://solstation.com/stars/la21185.htm

https://en.wikipedia.org/wiki/Lalande_21185

https://en.wikipedia.org/wiki/Stars_and_planetary_systems_in_fiction#Lal...