More Earthlike exoplanets!


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Astronomers using data from Kepler have discovered two stars, both with multiple orbiting Earth-sized planets. One has three planets all almost exactly the mass of Earth.

The first exoplanetary system is located in the star K2-239, characterized by these researchers as a red dwarf 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 planets 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. Although 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 our Sun, these researchers estimate that all planets discovered will have temperatures superficial tens of degrees higher than those of the planet Earth due to the strong radiation they receive in these close orbits to their stars.

Knowing more about the surface environments of these very Earthlike exoplanets, as hostile as they might be to life, would teach us a great deal about our own planet and its birth and evolution.

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5 comments

  • Localfluff

    TESS will make its first data download later in June. Someone estimated that 1/100,000 detected planets are expected to be Earth sized in the liquid water zone, only under the best circumstances. However, where there are large (multiple) transiting planets that TESS can detect, there are likely also small planets in that same transiting exoecliptic that follow ups can detect.

    Astronomy is going all sky! TESS maps the Solar neighborhood in a way that will direct further exoplanet research. GAIA maps our quadrant of the galaxy, finally figuring out where everything is which is the fundament of all astronomy. And LSST will continuously all transient changes on the sky every two or three nights. In a few years astronomers will know what to look for based on these and others all sky surveys. The productivity of astronomy is expected to increase. Observations used to be a bottleneck, but soon there will be too much data to handle it all.

  • Max

    One in 100,000 planets detected will be earth like Planets? That would be wonderful, let’s run the numbers.
    What is the chance that we would see a planet in transit across there sun?
    There are 360° in a circle, 1° = 60 in a arc minute. 1 arc minute = 60 arc second.
    360x60x60 = 1,296,000
    So a rough estimation would be out of every 1 million, 296,000 stars, we would see a planet in a perfect position to cause the dimming of a star.
    That’s being in the right place, but the odds that a planet being at the right time at the right distance… For example, Jupiter is huge. It’s distance from our star would make the dimming hard to detect. It’s slow orbital speed would cause the change in brightness to be so slow that it can be confused for a normal Solar variance. And this would not occur again for another 12 years.
    It’s a good thing that there are 100 to 200 billion stars in our galaxy…

    (Just a fun note, 1° is the equivalent of two moons stacked on top of each other. The moon is about 30 arc minutes across. The night sky moves more than this every 24 hours. 360° in a circle, 365 days in a year.
    One arc second is the equivalent of looking at the thickness of a dime from over a mile away. I admit, I do not know if nearby stars are thicker than this, I think not)

    I know the focus is to find planets in the green zone. Remember that the green zone mostly applies to where photosynthesis can take place. Thermal heat finds it difficult to penetrate any atmosphere making heat not such a great factor in the equation.
    The earth, for example, is in the green zone as well as the moon. But the moons average temperature is one hundred degrees colder than the earth. (not theory, actual measurements) “All heat is friction”.
    As a object drops into earths atmosphere, it heats up 5.4° for every thousand feet it falls. (depending on humidity) when you go camping on a mountain, or go up in a plane, the temperature drops 5.4° for every thousand feet you rise above sea level. When a storm “Low pressure system” moves over your area, the temperature drops in relation to the mercury dropping. The same with the eye of a hurricane. Just try to find that in any of the global warming literature or theories or models… Perpetual motion is said to be impossible. And yet atoms vibrate perpetually.
    The more pressure you apply to atoms, the faster they vibrate. This can be measured in the heat produced. Where is the highest temperatures recorded? Ground level. The deeper the ground level, like Death Valley, the higher the temperatures.
    The suns influence can be measured by the difference from the high of the day subtracting the low of the night. (clouds will influence this number greatly, as much as 90%)
    The reason I bring this up is when I was looking on Wikipedia for earths mass equivalence in our solar system ( Mercury, 1/20th. Mars, 1/10th. Venus .815 of earths mass. Next smallest is Uranus at 14.5)
    I saw a change in the “Suns theoretical problems”. There are only two now where there was many more 10 years ago. Apparently they have given up trying to explain the chronal heating problems without proof. With the solar probe to be launched soon, they are slowly coming around to Nanoflares (or microflares) as was announced when the Soho satellite was first launched must be near 30 years ago. (I listened to the scientist who wrote the book “Our or The Mantic Sun” live on the BBC. After buying my first computer I listen to that interview again on the “way back machine” thinking this will change everything)( I should have bought the book, can’t find it anywhere)
    The solar probe has been named after the man accredited with being first to describe an electric Sun.
    From Wikipedia:

    “Currently, it is unclear whether waves are an efficient heating mechanism. All waves except Alfvén waves have been found to dissipate or refract before reaching the corona.[163] In addition, Alfvén waves do not easily dissipate in the corona. Current research focus has therefore shifted towards flare heating mechanisms.[101]”

    This is good news, even though they took down the information describing the “factor of three minimum” lack of radiation from the Sun associated with all nuclear fusion.
    (If the Suns heat and light was nuclear in origin, it would render our solar system life less from the radiation byproduct)
    Sorry, I’ve had too much coffee and too much time today…

  • Localfluff

    @Max
    Kepler observed 150,000 stars and has found 2,327 confirmed exoplanets. So 1½%. And as many candidates out of which about 90% are expected to be real, so rather 3%. Because they are so close in to the star’s surface, those most easiest to detect. It of course depends on the telescope. TESS is expected to find 100,000 if not 200,000 exoplanets (or systems) on over 80% of the sky. This is promising to be a worthy follow up of Kepler.

    All stars, except a few nearby supergiants, are point sources. Nothing can be resolved of them, they are just a dot even in the most powerful telescopes. The so called light curve shows the intensity of that dot over time. Transits, starspots and helioseismology and more is cleverly derived from that dot. So they are not even like a dime a mile away. Although astronomers talk about resolution of milliarcseconds and microarcseconds, it’s not enough. Even the local universe is ridiculously big.

    I won’t comment your Sun stuff :-) About the planets, note that every planet in the Solar system is more massive than the sum of all smaller planets! For example, Neptune is more massive than Uranus, Earth, Venus, Mars and Mercury taken together. Even though Uranus is larger (thus the term sub-Neptunes because for transits the size, not the mass, is observed). The extreme diversity of the planets in the Solar System implies that the exoplanets can be a varied lot as well. The sample viewed is however very biased. The reason that so few exoplanets with rings have been found is that rings mostly consist of ice and thus only on planets beyond the frost line, with long orbital periods and thus rare transits. And not one double planet has been found. I.e. a Pluto/Charon like system but with two much larger planets. With so many binary asteroids and stars, and Neptune having captured Triton, I would’ve thought that double planets were more common. But again, perhaps not very stable so close to their star.

  • Joe

    Worlds without end in a universe we have a hard time of fathoming

  • pzatchok

    By the time we ever get to these planets and places we will not need to.
    We will be permanently a space bases race. landing on planets only to establish colonies because we want to, not because we need to.

    Outer space has everything we need to thrive as a people. We just need a bit more technology to make use of it.
    Planets might be nice but they offer that stuff called gravity that makes harvesting from them a problem.

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