These are *not* the smallest exoplanets found yet. That honor goes to the pulsar planets that were discovered in the early 1990′s. Their maximum masses derived from radial velocity were near or well below the mass of Earth, including this one:

http://en.wikipedia.org/wiki/PSR_B1257%2B12_A

Which is, in fact, the smallest exoplanet ever discovered (in 1994), weighing in at only twice the mass of Earth’s *Moon*, making it much smaller than all other exoplanets discovered so far, and in fact smaller than any of the 8 planets in our solar system.

I do occasionally see articles that give a nod to this by adding “around any main-sequence star” after “smallest yet discovered,” which is at least technically accurate.

It seems like a disservice to those early planet hunters to always overlook that achievement, especially because most articles on exoplanets also indicate the “first” exoplanet discovered was 51 Pegasi b in 1995, which is also completely untrue.

Second, it shows that red dwarf stars can form and hold onto planets… which itself is important because red dwarfs are by far the most common kind of star in the Universe. They make up roughly 80% of the total number of stars!

Plus while they used to be considered unlikely hosts for habitable planets as Ken Croswell points out here :

http://kencroswell.com/HowRedDwarfsProtectTheirPlanets.html

& here :

http://kencroswell.com/reddwarflife.html

Red dwarfs may be a lot better suited to hosting life than we used to think.

Mind you, coping with red dwarf flares – and many of them really do flare dramatically – could present life on planets necessarily tucked in close with some major issues. As kaler notes on page 31, “The Faintest Stars” article by James B. Kaler , in ‘Astronomy’magazine, August, 1991 :

“Imagine M-dwarf [red dwarf - ed.] bathing on the beach and having your star suddenly -with no warning at all – become ten times brighter.”

Yikes!

Can anyone imagine our Sun becoming even twice as bright abruptly?

As always, there’s just so much still to learn.

Wondering more than ever before if the nearer red dwarf stars – eg. Proxima Centauri, Barnard’s Star, Wolf 359 – have planets, what they’re like and when, if ever, we’ll know? A twin of Barnard’s Star eh?

Ah, for FTL travel, sigh.

The more of these newly-detected planets we catalog, the less appropriate it will be to use distinct terminology. From a scientific standpoint, what justifies a vocabulary for discussing planetary bodies which implicitly views the ones in our own system as somehow inherently special or different?

Possible Disintegrating Short-Period Super-Mercury Orbiting KIC 12557548

The exoplanet low mass limbo just keeps getting lower!

Down to the mass of Mars – wow.

Surely we must be pushing the limit of what they can detect now – but does have me wondering how much lower (mass~wise) they can go. All the way to Pluto-mass & beyond? Also wonder if further study could use perturbations of these rock dwarfs to detect any higher (or even equally low) planets further out?

No too big secret that NASA has gotten toughest question to fund future & current projects. I’d like to offer you game-changing strategy: One & First among the Key Factors is to become financially independent, space tourism has really great potential to be first having extra incomes, but common mistake of start-ups like SpaceX is the way to excite customers. Ticket to Space is too expensive even for far not poor personas, but fortunately this obstacle can be broken through with lottery schemes to sell tickets + that way makes possible to get many times more income to advance than Just to search wealthy ones.

Aforesaid text is only smallest part of the strategy to turn Space Industry from ugly duck to blossoming Swan.

My the best wishes.

P. S.

+ one wonderful & useful moment must be mentioned: the more NASA will be self-funded, the more money from government will be given to NASA.

I second that. I didn’t want to nitpick either, but then, what is science about but nitpicking everything?
But yeah, (very) large numbers! I wonder if somewhere out there is a “smoke ring” as in Larry Niven’s “The Integral Trees”?

As far as I know no one thinks today the asteroid belt would have aggregated to a planet. (Wasn’t that the idea of one early astronomer all by himself, btw?)

What happened was that no planet kicked it sufficiently clean after planet/planetesimal formation, same as the Kuipers are left and so on.

The resemblance between so many of these super-Earth systems and the Jupiter system is interesting, even though there’s obviously a detection bias involved which favours finding these types of systems over analogues to our much more widely-spaced inner solar system.

Diagrams invariably inflate the size of things so they are visible as more than dots, but that throws off the layman’s sense of scale. So I love to see astronomical diagrams done at correct scale. So many people have no concept of the actual distances involved and how much empty space is out there.

Average orbital radii:
Io: 422,000 km = 5.9 R(J)
Europa: 671,100 km =9.4 R(J)
Ganymede: 1,070,000 km = 15.0 R(J)
Callisto: 1,883,000 km = 26.3 R(J)

So, no, the sizes and distances are not to the same scale.

I’m dubious, as close binary and trinary systems should be disruptive enough to prevent planet formation, just as Jupiter prevented the asteroid belt from becoming a planet.

Perhaps, but Jupiter didn’t prevent the formation of the dwarf planet Ceres. So if you’re of the opinion that dwarf planets should be considered planets too….

Everything there is to scale: the relative size of the star, the planets, Jupiter, and its moons.

The relative sizes and the relative distances are to scale, but surely the distances and sizes are not to scale with each other, right? Io does not orbit less than a Jupiter-diameter away from Jupiter’s surface, does it?

The artwork above drives that point home. Everything there is to scale: the relative size of the star, the planets, Jupiter, and its moons.

Is everything really to scale, or just the relative sizes? Cause it looks to my untrained eye like the planets are really close to the star, and that the moons are too close to Jupiter.

Oops… Just noticed lunchstealer beat me to this. Oh well, I already posted it, so I guess I’ll leave it up.

Planets around close binaries and triple stars? Easy — they orbit far out around both/all stars in the system. The hypothesis is that all or nearly all stars have planets, not that they all have planets in their habitable zones.