Researchers discover a system with three Earth-sized planets

Researchers discover a system with three Earth-sized planets
Credit: Instituto de Astrofísica de Canarias

The Instituto de Astrofísica de Canarias (IAC) and the University of Oviedo present today the discovery of two new planetary systems, one of them hosting three planets the same size as the Earth.

The information about these new exoplanets has been obtained from the data collected by the K2 mission of NASA's Kepler satellite, which started in November 2013. The work, which will be published in the Monthly Notices of the Royal Astronomical Society (MNRAS), reveals the existence of two new planetary systems detected from the eclipses they produce in the stellar light of their respective stars. In the research team led jointly by Javier de Cos at the University of Oviedo, and Rafael Rebolo at the IAC, participate, along with researchers from these two centres, others from the University of Geneva and the Gran Telescopio Canarias (GTC).

The first exoplanetary system is located in the star K2-239, characterized as a type M3V from observations made with the Gran Telescopio Canarias (GTC), at the Roque de los Muchachos Observatory (Garafía, La Palma). It is located in the constellation of the Sextant at 50 parsecs from the sun (at about 160 light years). It has a compact system of at least three rocky of similar size to the Earth (1.1, 1.0 and 1.1 Earth radii) that orbit the star every 5.2, 7.8 and 10.1 days, respectively.

The other red dwarf star, called K2-240, has two super-Earth-like planets about twice the size of our planet. The atmospheric temperature of red dwarf stars around which these planets revolve is 3,450 and 3,800 K respectively, almost half the temperature of the sun. These researchers estimate that all planets discovered will have temperatures tens of degrees higher than those of Earth due to the strong radiation they receive in these close orbits to their .

Future observation campaigns with the new James Webb space telescope will characterize the composition of the atmospheres of the discovered planets. Spectroscopic observations with the ESPRESSO instrument, installed in the Very Large Telescope (VLT), of the European Southern Observatory (ESO), or with future spectrographs in the GTC or in new astronomical facilities, such as the ELT or the TMT, will be crucial to determine the masses, densities and physical properties of these planets.

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More information: Díez Alonso, J.I. et al. Two planetary systems with transiting Earth-size and super-Earth planets orbiting late-type dwarf stars, Monthly Notices of the Royal Astronomical Society.
Citation: Researchers discover a system with three Earth-sized planets (2018, June 8) retrieved 19 October 2019 from
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Jun 08, 2018
The good news is; our technology and methods of analyzing data continue to improve in sophistication and sensitivity.

The bad news; all we are discovering are crap planets in ridiculous orbits around baleful starlets.

Yep, Stupid Design....

Perhaps it get better press if I rename SD. How about something like, Stochastic Actively Disruptive Systematic Incoherencey Theorem?

Yes, SADSIT. Now that makes so much more sense than speculating about drunken godlings as cthonic jokers? Though I must admit, I'm going to miss those flying cream pies!

Jun 08, 2018
rrwillsj, I wouldn't write those planets off as "crap" just yet. According to the paper, the equilibrium temperatures of the five planets range from 389 K (240 F) to 586 K (595 F). Maybe the polar regions of the coolest planet (K2-240c) are already at fairly comfortable temperatures. Maybe you want to wait until the middle of winter to visit, if it has tilt. Maybe there are large mountains in one or both polar regions with cooler parts near their summits, who knows?

Of course that is only the beginning of the "what-if" scenarios. How about, what if the atmospheres of all five planets contained massive quantities of light blocking atmospheric particulates that keep all five of those planets cool? What if somebody put large light blocking structures around K2-240c to cool it down to Earth-like temperatures?

Finally, what if all five of those planets have already been terraformed by a species not so quick to pass judgement on something they know nearly nothing about? :-)

Jun 08, 2018
Mark, if those 'aliens' have x-ray proof lead carapaces? Sure, why not. But then again, if these are suppose to be intelligent sophonts? That these three hellholes are the best they can come up with for colonizing? Makes that whole intelligence thing they got going a rather dubiously losing proposition.

Hey, that puts them on par with the Human Race! Neck and neck to discover which is the biggest loser among this Galaxy's saps.

Jun 10, 2018
And I just realized. if these three infernal pits are in serious contention as "Earth-like"? Then we have to add our own swift-running Mercury to the list of "I-coulda-been-a-contender" in this system. That'd bring a whole new meaning to your Mother's advice "Child, don't forget to take your parasol with you, when you go outside."

Jun 11, 2018
Earthlike just means they are of comparable radius to Earth. The label has nothing to do with habitability.

all we are discovering are crap planets in ridiculous orbits

And yes, we are finding stuff in these orbits because those are, with out current techniques, findable. Planets like Earth in a similar orbit are a lot harder to detect because
- they are unlikely to pass in front of their parent star (and if they do the effect is so small as to be hard to notice from this distance). For close-in planets the probability is a lot higher.
- if they do pass in front of the star they do not do so often enough for repeated analysis that would confirm their position/orbit. Close-in planets do this and are therefore easier to detect
- The are not massive enough to affect their parent star's motion at that distance (unlike Jupters and super-Jupiters which are detectable further out)

As for the 'starlets': The majority of stars are smaller than our sun. No surprise there.

Jun 11, 2018
a-p, you've made a strong argument for continuing efforts to develop new technologies & more sensitive instrumentation.

However those are only part of what it will take to improve our knowledge of the cosmos. I think it is important that the methodology, the ethics for analysis & verification of data also need to improve.

In the sense that we should not be encouraging clickbait headlines or the perception that scientific competition is as trivial as sports championships.

It is foolish to be encouraging researchers to grab headlines with unsupported claims. Speculation & hypothesis help power scientific achievements. However it is repeatable experimentation with strict code of verification that confirms the validity of a theory.

Or disproves what seemed like a good idea. Success & failure are equal measures for innovation.

There is such a fear of being seen as failing. We should realize that science is a continuous process. Without any discernible ending.

Jun 11, 2018
Researchers discover a system with three Earth-sized planets

With three planets within plus or minus 10% of Earth diameter, this does not look like a clickbait headline to me.

Jun 12, 2018
So Mark, if you find listing these three planets as "Earth-Like" based on estimated diameters? That would qualify Venus based on it's size alone. We just ignore all the other disabilities.

And again I ask. Claiming Earth-like status for these three? Would it not be fair to include Mercury upon that pedestal?

Which is why I am arguing that the term "Earth-like' is being grossly abused just to get publicity!

Even if your fabulist speculation that "Aliens" might be capable of inhabiting those three worlds? If they have such an advanced technology and economic surplus? Why would they bother?

Come to think of it, I am amused to accept your hypothesis because you are unwittingly supporting my guesstimate that the universe consists mainly of "crap" planets. And this was the very best the 'Aliens' could find to inhabit.

Okay, works for me. Thanks Mark.

Jun 13, 2018
"Earth-sized," not necessarily Earth-like in any way other than size.

We have known for a long time that the vast majority of planets are not going to be immediately habitable for people and the plants and animals we like to have around. Just look at our own solar system. Near instantaneous death for being unprotected on any one of them.

Jun 25, 2018
As a note, if you maliciously attack science like rrwillsj here, make sure your reading comprehension of English is up to snuff. Attacking a strawman torpedoes your whole argument and, yes, expose it as without forethought malicious and so meaningless for others.

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