Kepler confirms three worlds 40 light-years away are Earth-sized

[kevindavis007]

The TRAPPIST-1 star system houses three planets, which have now been confirmed to be Earth-sized and possibly rocky.

Key Points

• The Kepler telescope has proved that three promising planets around the star TRAPPIST-1 are Earth-sized.
• These worlds 40 light-years away may be rocky like Earth, and at least one is in the habitable zone.

When it comes to exoplanets, astronomers have realized that they only know the properties of the planets they discover as well as they know the properties of the stars being orbited. For a planet's size, precisely characterizing the host star can mean the difference in our understanding of whether a distant world is small like Earth or huge like Jupiter.


For astronomers to determine the size of an exoplanet—planets outside the solar system—depends critically on knowing not only the radius of its host star but also whether that star is single or has a close companion. Consider that about half of the stars in the sky are not one but two stars orbiting around each other, this makes knowing the binary property of a star paramount.


One particularly interesting and relatively nearby star, named TRAPPIST-1, recently caught the attention of a team of researchers. They wanted to determine if TRAPPIST-1, which is home to three small, potentially rocky planets—one of which orbits in the temperate habitable zone where liquid water might pool on the surface—was a single star like the sun, or if it had a companion star. If TRAPPIST-1 did have a companion star, the discovered planets will have larger sizes, possibly large enough to be ice giants similar to Neptune.


    "Knowing that a terrestrial-size potentially rocky planet orbits in the habitable zone of a star only 40 light-years from the Earth is an awesome finding."
    - Steve Howell, NASA


If an exoplanet orbits a star in a binary system but astronomers believe the starlight captured by the telescope is from a single star, the real radius of the planet will be larger than measured. The difference in the measured size of the exoplanet can be small ranging from 10 percent to more than a factor of two in size, depending on the brightness of the companion star in the system.


To confirm or deny the single star nature of TRAPPIST-1, Steve Howell, senior research scientist at NASA's Ames Research Center at Moffett Field, California, led an investigation of the star. Using a specially designed camera, called the Differential Speckle Survey Instrument or DSSI, Howell and his team measured the rapid disturbances in the light emitted by the star caused by the Earth’s atmosphere and corrected for them. The resultant high-resolution image revealed that the light coming from the TRAPPIST-1 system is from a single star.


With the confirmation that no other companion star resides in the vicinity of TRAPPIST-1, the research team's result validates not only that transiting planets are responsible for the periodic dips seen in the star’s brightness but that they are indeed Earth-size and may likely to be rocky worlds.


"Knowing that a terrestrial-size potentially rocky planet orbits in the habitable zone of a star only 40 light-years from the Earth is an awesome finding," said Howell. “The TRAPPIST-1 system will continue to be studied in great detail as these transiting exoplanets offer one of the best chances to characterize the atmosphere of an alien world."


Mounted on the 8-meter Gemini Observatory South telescope in Chile, the DSSI provided astronomers with the highest resolution images available today from a single ground-based telescope. The nearness of TRAPPIST-1 allowed astronomers to peer deep into the system, looking closer than Mercury's orbit to our sun.


The paper the result is based on is published in the September 13th issue of The Astrophysical Journal Letters.


Read more: http://www.isn-news.net/2016/09/kepler-confirms-three-worlds-40-light.html

[Gefn]

Wow.

I really wish we had a space ping.

[Ghost Bear]

When you've read science fiction your whole life, as I have, 40 light years seems like nothing; just down the street, space-wise. But in the actual universe limited by the speed of light and an 80-year human lifespan, I don't see humans ever actually sending a probe there, let alone visiting in person. The travel time, even if we had some propulsion system that could build up a velocity of some appreciable percentage of light speed, would just take too long.  We need to either find some way around the light speed barrier, or greatly extend the human lifespan, before exploring even 40 light years away can become a possibility.

[kevindavis007]

When you've read science fiction your whole life, as I have, 40 light years seems like nothing; just down the street, space-wise. But in the actual universe limited by the speed of light and an 80-year human lifespan, I don't see humans ever actually sending a probe there, let alone visiting in person. The travel time, even if we had some propulsion system that could build up a velocity of some appreciable percentage of light speed, would just take too long.  We need to either find some way around the light speed barrier, or greatly extend the human lifespan, before exploring even 40 light years away can become a possibility.

I would say that at the end of this century we could have FTL (Warp Speed, Hyperdrive,etc..).. Also there is a possibility of using either Generational Ships or sleeper ships.

[Cripplecreek]

I would say that at the end of this century we could have FTL (Warp Speed, Hyperdrive,etc..).. Also there is a possibility of using either Generational Ships or sleeper ships.

Lots of interesting research into propulsion systems and long term human hibernation going on and I suspect that growing knowledge of exoplanets is a major driver of that research.

Columbus was headed for Asia. He knew it was there but had no clue how far it was, what he might encounter, or even if he could make it. In the process he charted things like ocean currents and winds which were used by explorers who followed.

In fact, I've read that ship technology began to change quickly with the new trans oceanic travels.

[kevindavis007]

Lots of interesting research into propulsion systems and long term human hibernation going on and I suspect that growing knowledge of exoplanets is a major driver of that research.

Columbus was headed for Asia. He knew it was there but had no clue how far it was, what he might encounter, or even if he could make it. In the process he charted things like ocean currents and winds which were used by explorers who followed.

In fact, I've read that ship technology began to change quickly with the new trans oceanic travels.

I suspect you are right.

[Ghost Bear]

I would say that at the end of this century we could have FTL (Warp Speed, Hyperdrive,etc..).. Also there is a possibility of using either Generational Ships or sleeper ships.

The problem isn't the lifespan of the astronauts making the voyage, the problem is with the humans back on Earth. What government, corporation, or individual is going to support a multi-billion dollar effort that won't see any possible payoff for at least 80 years (40 there, 40 back, at light speed) or more likely at the speeds that we could realistically achieve, hundreds of years?  What government or corporation would still be in existence after that long? Sure, the crew could be in stasis of some kind, or multi-generational, but for people back on Earth stuck with 80 year lifespans, there would never be any hope of knowing the outcome of the trip.  And few people would support the kind of effort needed, knowing they would never see any payoff. 

[geronl]

What government, corporation, or individual is going to support a multi-billion dollar effort that won't see any possible payoff for at least 80 years (40 there, 40 back, at light speed) or more likely at the speeds that we could realistically achieve, hundreds of years?

Well, Government does it all the time. They spend money on things with no possible payoff ever.

[geronl]

Good, now we need to set up special cameras to investigate the likeliest ones.