History UsefulNotes / LocalStars

21st Oct '16 12:43:59 AM harharhar
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A brown dwarf who not only has the third-highest proper motion of all observed stars (behind the aforementioned Barnard's Star and a more-distant [[https://en.wikipedia.org/wiki/Kapteyn%27s_Star Kapteyn's Star]]), but is the coldest 'star' currently known (observational estimates puts its ''maximum'' temperature at a mere 260 K/−13 °C/8 °F, ''lower than water's freezing point!'')

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A brown dwarf who not only has the third-highest proper motion of all observed stars (behind the aforementioned Barnard's Star and a more-distant [[https://en.wikipedia.org/wiki/Kapteyn%27s_Star Kapteyn's Star]]), but is the coldest 'star' star currently known (observational estimates puts its ''maximum'' temperature at a mere 260 K/−13 °C/8 °F, ''lower ''colder than water's freezing point!'')
water!'')
5th Sep '16 6:24:19 PM tracer
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In August 2016 the discovery of an Earth-like world orbiting the star inside the habitable zone [[http://www.popularmechanics.com/space/deep-space/news/a22522/nearest-planet-proxima-b/ was announced]]., tentatively named Proxima b.

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In August 2016 the discovery of an Earth-like world world[[note]]"Earthlike" meaning it has a mass similar to Earth, and receives about as much energy from its parent star as the Earth does. This does not mean it has oceans, an oxygen atmosphere, or any of the other features that make Earth distinctive.[[/note]] orbiting the star inside the habitable zone [[http://www.popularmechanics.com/space/deep-space/news/a22522/nearest-planet-proxima-b/ was announced]]., tentatively named Proxima b.
5th Sep '16 6:22:16 PM tracer
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B orbits A ([[FromACertainPointOfView or vice versa]]) in an elliptical orbit that would roughly range between Saturn and Uranus in our solar system. With enough room for close-in planetary systems around each star, you'd have a decent chance of getting an Earth-like planet there -- and in fact, we've found one orbiting B. In addition, we've pretty much confirmed that neither star of this pair has a [[AsteroidThicket debris disk]] orbiting around it like Vega does. This is good sign that more planets might exist, since forming planets would have swept up any orbiting debris near their orbit.

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B orbits A ([[FromACertainPointOfView or vice versa]]) in an elliptical orbit that would roughly range between Saturn and Uranus in our solar system. With enough room for close-in planetary systems around each star, you'd have a decent chance of getting an Earth-like planet there -- and in fact, we've in 2012 we ''thought'' we found one orbiting B. (Sadly, this turned out to be a blip in the data that disappeared with further observation.) In addition, we've pretty much confirmed that neither star of this pair has a [[AsteroidThicket debris disk]] orbiting around it like Vega does. This is a good sign that more planets might exist, since forming planets would have swept up any orbiting debris near their orbit.



In 2012, it was announced that a planet had been discovered orbiting Alpha Centauri B. It was Earth-sized (about 1.13 times the mass of the Earth) and orbited only a scant 6 million kilometers from B, giving it an orbital period that lasted a mere three-and-a-quarter ''days''. (It would also, most likely, be tidally locked, so one half of the planet is a molten sea of lava, and the other is a huge icecap.) Sadly, it appears that this announcement was [[http://www.slate.com/blogs/bad_astronomy/2016/01/20/alpha_centauri_planet_is_almost_certainly_not_real.html premature]].

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In 2012, it was announced that a planet had been discovered orbiting Alpha Centauri B. It was Earth-sized (about 1.13 times the mass of the Earth) and orbited only a scant 6 million kilometers from B, giving it an orbital period that lasted a mere three-and-a-quarter ''days''. (It would also, most likely, be have been tidally locked, so one half of the planet is would be a molten sea of lava, and the other is a huge icecap.) Sadly, it appears that this announcement was [[http://www.slate.com/blogs/bad_astronomy/2016/01/20/alpha_centauri_planet_is_almost_certainly_not_real.html premature]].
24th Aug '16 11:00:11 PM aurora369
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!!''Mu Arae (49.8 ly)''

This G3 star, which is close to the end of its main-sequence lifespan, is one of the first stars to be assigned new proper names by the IAU: it is also known as Cervantes, after the famous Spanish writer. Its planets, of which it has four confirmed, are named after Cervantes' characters: Quixote, Dulcinea, Rocinante and Sancho. They are all gas giants, Dulcinea being the smallest one (a "hot Neptune") and Sancho the largest (a superjovian similar to our own Jupiter). Terrestrial planets, or terrestrial gas giant moons, are likely. The gas giant Quixote (a superjovian as well) sits in the habitable zone, so it would be a good place to find a big habitable moon.
24th Aug '16 10:34:52 PM aurora369
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While there are probably planets in the habitable zone here, finding life "[[Franchise/StarTrek as we know it]]" is improbable, as the entire system is far too young.[[note]]Our sun is is 4.57 billion years old. Earth came around about 30 million years later, and the simplest forms of life 740 million after that (or so sayeth [[http://en.wikipedia.org/wiki/Sun#Life_cycle the]] [[http://en.wikipedia.org/wiki/Age_of_the_Earth other]] [[http://en.wikipedia.org/wiki/Timeline_of_evolution wiki]]).[[/note]] Epsilon Eridani ''itself'' is at most 1 billion years old, probably younger, and its planets would be younger still. Life there is at best in the "single-celled organism" phase--if not the "parents grunting and groaning [[RightThroughTheWall in the next apartment over]]" bit. Note that in planetary formation science, grunting and groaning involves loads and loads of [[EarthShatteringKaboom planetesimals colliding]]. Generally, the planetary system of Epsilon Eridani is yet another primordial jumble of dozens of small planetoids, rocks and dust.

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While there are probably planets in the habitable zone here, finding life "[[Franchise/StarTrek as we know it]]" is improbable, as the entire system is far too young.[[note]]Our sun is is 4.57 billion years old. Earth came around about 30 million years later, and the simplest forms of life 740 million after that (or so sayeth [[http://en.wikipedia.org/wiki/Sun#Life_cycle the]] [[http://en.wikipedia.org/wiki/Age_of_the_Earth other]] [[http://en.wikipedia.org/wiki/Timeline_of_evolution wiki]]).[[/note]] Epsilon Eridani ''itself'' is at most 1 billion years old, probably younger, and its planets would be younger still. Life there is at best in the "single-celled organism" phase--if not the "parents grunting and groaning [[RightThroughTheWall in the next apartment over]]" bit. Note that in planetary formation science, grunting and groaning involves loads and loads of [[EarthShatteringKaboom planetesimals colliding]]. Generally, the planetary system of Epsilon Eridani is yet another primordial jumble of dozens of small planetoids, rocks and dust.
dust. One gas giant is suspected, and it even has a proper name: Aegir.
24th Aug '16 10:22:36 AM AzureOwl
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Added DiffLines:

In August 2016 the discovery of an Earth-like world orbiting the star inside the habitable zone [[http://www.popularmechanics.com/space/deep-space/news/a22522/nearest-planet-proxima-b/ was announced]]., tentatively named Proxima b.
8th Aug '16 12:06:38 AM UmbrellasWereAwesome
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* In the ''Franchise/{{Halo}}'' universe, the planet Reach is located here.

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* In the ''Franchise/{{Halo}}'' universe, the planet Reach [[VideoGame/HaloReach Reach]] is located here.
8th Aug '16 12:06:09 AM UmbrellasWereAwesome
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* In the Franchise/{{Halo}} universe, the planet Reach is located here.

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* In the Franchise/{{Halo}} ''Franchise/{{Halo}}'' universe, the planet Reach is located here.
6th Aug '16 9:56:26 AM karstovich2
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Located in Centaurus, this is the closest star to us. A member of the triple system of Alpha Centauri, but far enough from the two larger members (about 0.21 ly) to be considered a separate star system for space travelers. Despite being the closest star to the Solar system, it (like all red dwarfs) is too dim to be seen with the naked eye from Earth. From a planet orbiting Alpha Centauri A or B, it would appear as an unremarkable fifth-magnitude star.

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Located in Centaurus, this is the closest star to us. A member of the triple system of Alpha Centauri, Centauri (its systematic name is Alpha Centauri C) but far enough from the two larger members (about 0.21 ly) to be considered a separate star system for space travelers. Despite being the closest star to the Solar system, it (like all red dwarfs) is too dim to be seen with the naked eye from Earth. From a planet orbiting Alpha Centauri A or B, it would appear as an unremarkable fifth-magnitude star.
30th May '16 5:01:25 PM Marlfox24
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An orange ([=K1V=]) star and among the closest systems likely to have a habitable planet. (The only closer one is Alpha Centauri). There may be a brown dwarf or a very dim red dwarf orbiting it widely. May have planets a lot of astronomical attention in that field looks over here, as do searches for intelligent alien life of the "point a radio telescope at it and see if we hear anything" variety. NASA has marked them as #9 for their planned Terrestrial Planet Finder mission.

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An orange ([=K1V=]) star and among the closest systems likely to have a habitable planet. (The only closer one is Alpha Centauri). There may be a brown dwarf or a very dim red dwarf orbiting it widely. May have planets a lot of astronomical attention in that field looks over here, as do searches for intelligent alien life of the "point a radio telescope at it and see if we hear anything" variety. NASA has marked them as #9 for their planned Terrestrial Planet Finder mission.
variety.



The closest solitary Sun-like star to us, so appears a lot in fiction, and is #3 on the list for NASA's planned Terrestrial Planet Finder mission. Can be seen in the northern sky as a third-magnitude star it's clearly visible but you'll probably only notice it specifically if you're looking for it. It's only about half as luminous as the Sun, despite being in the same spectral class - Tau Ceti is a [=G9V=], Sol is a [=G2V=]. Tau Ceti also has only about 30% as high a concentration of heavy elements as the sun does; presumably the planets orbiting it are equally low in heavy elements.

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The closest solitary Sun-like star to us, so appears a lot in fiction, and is #3 on the list for NASA's planned Terrestrial Planet Finder mission.fiction. Can be seen in the northern sky as a third-magnitude star it's clearly visible but you'll probably only notice it specifically if you're looking for it. It's only about half as luminous as the Sun, despite being in the same spectral class - Tau Ceti is a [=G9V=], Sol is a [=G2V=]. Tau Ceti also has only about 30% as high a concentration of heavy elements as the sun does; presumably the planets orbiting it are equally low in heavy elements.



Triple system with a main orange ([=K1V=]), a white dwarf (DA) and red dwarf ([=M5V=]). #10 on the list for NASA's planned Terrestrial Planet Finder mission.

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Triple system with a main orange ([=K1V=]), a white dwarf (DA) and red dwarf ([=M5V=]). #10 on the list for NASA's planned Terrestrial Planet Finder mission.
([=M5V=]).



A yellow G class, very similar to our Sun. Has an orange [=K7V=] companion, Eta Cassiopeiae B, which is a likely candidate for Earthlike planets, too. The distance between the two stars is 77 au, which is more than enough for both stars to have full planet systems with terrestrials and gas giants. Larger-than-Jupiter gas giants and brown dwarfs, though, are highly unlikely, since they would be already detected. #4 on the list for NASA's planned Terrestrial Planet Finder mission.

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A yellow G class, very similar to our Sun. Has an orange [=K7V=] companion, Eta Cassiopeiae B, which is a likely candidate for Earthlike planets, too. The distance between the two stars is 77 au, which is more than enough for both stars to have full planet systems with terrestrials and gas giants. Larger-than-Jupiter gas giants and brown dwarfs, though, are highly unlikely, since they would be already detected. #4 on the list for NASA's planned Terrestrial Planet Finder mission.
detected.



Another yellow subgiant ([=G2IV=]), similar to Delta Pavonis. A large, four times the mass of Jupiter, gas giant is suspected in a roughly 8 AU orbit. In our skies looks like the brightest star near the South Pole. It's #5 on NASA's Terrestrial Planet Finder mission.

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Another yellow subgiant ([=G2IV=]), similar to Delta Pavonis. A large, four times the mass of Jupiter, gas giant is suspected in a roughly 8 AU orbit. In our skies looks like the brightest star near the South Pole. It's #5 on NASA's Terrestrial Planet Finder mission.
Pole.



A yellow-white (F6) star in Orion, three times as bright as the Sun. Some kind of substellar companion is detected, which could be a large gas giant planet (or several) or a brown dwarf, with an approximate semimajor axis of 5.2 AU. This star is largely forgotten by science fiction, but scores a #7 on the NASA Terrestrial Planet Finder list.

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A yellow-white (F6) star in Orion, three times as bright as the Sun. Some kind of substellar companion is detected, which could be a large gas giant planet (or several) or a brown dwarf, with an approximate semimajor axis of 5.2 AU. This star is largely forgotten by science fiction, but scores a #7 on the NASA Terrestrial Planet Finder list.
AU.



A binary dwarf star in Cancer; the primary star, 55 Cancri A, is a class [=G8V=] yellow dwarf, and notable for having the third-biggest known solar system (after ours, of course, and Gliese 581's), with 5 planets. 55 Cancri f is the most interesting of these, as it orbits entirely within 55 Cancri A's habitable zone (in fact, it is the first planet discovered to do so). 55 Cancri f is itself a gas giant roughly half the mass of Saturn, but if it is anything like our gas giants, it will have a veritable swarm of moons, some of which may be conducive to life, and so 55 Cancri A has the #63 slot for NASA's planned Terrestrial Planet Finder mission. A radio message has been beamed to this star's vicinity; it will arrive in 2044.

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A binary dwarf star in Cancer; the primary star, 55 Cancri A, is a class [=G8V=] yellow dwarf, and notable for having the third-biggest known solar system (after ours, of course, and Gliese 581's), with 5 planets. 55 Cancri f is the most interesting of these, as it orbits entirely within 55 Cancri A's habitable zone (in fact, it is the first planet discovered to do so). 55 Cancri f is itself a gas giant roughly half the mass of Saturn, but if it is anything like our gas giants, it will have a veritable swarm of moons, some of which may be conducive to life, and so 55 Cancri A has the #63 slot for NASA's planned Terrestrial Planet Finder mission.life. A radio message has been beamed to this star's vicinity; it will arrive in 2044.
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