3 planets around Wolf 1061 at 14 l.y (one in HZ)

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3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by Led_Zep on 16th December 2015, 10:32 am

https://www.science.unsw.edu.au/news/discovery-nearby-star-hosts-closest-alien-planet-in-habitable-zone

UNSW Australia astronomers have discovered the closest potentially habitable planet found outside our solar system so far, orbiting a star just 14 light years away.
The planet, more than four times the mass of the Earth, is one of three that the team detected around a red dwarf star called Wolf 1061.
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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by Edasich on 16th December 2015, 12:22 pm

Nice find, Led_Zep! Very Happy
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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by tommi59 on 16th December 2015, 3:13 pm

Planet d receives almost the same insolation like gj 581d if the latter exist
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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by Sirius_Alpha on 16th December 2015, 11:07 pm


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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by Led_Zep on 17th December 2015, 11:02 am

page 21 table 1 :

Transit probability 14.0% for planet b 5.9% for planet c and 2.6% for planet d
A good target for the mission CHEOPS (ESA, launch 2017)
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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by Lazarus on 17th December 2015, 12:25 pm

Given the mass-inclination degeneracy I wouldn't be surprised if the "habitable" planets are actually mini-Neptunes rather than super-Earths. Nevertheless, always nice to see discoveries around nearby stars, rather than objects hundreds of light years away. (Though even 14 light years is still completely out of reach.)
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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by Lazarus on 22nd December 2015, 6:26 pm

Wolf 1061 now on Centauri Dreams and featured in the "Habitable Planet Reality Check" series at Drew Ex Machina.
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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by Led_Zep on 1st January 2017, 10:21 pm

https://arxiv.org/abs/1612.09324

Characterization of the Wolf 1061 Planetary System

A critical component of exoplanetary studies is an exhaustive characterization of the host star, from which the planetary properties are frequently derived. Of particular value are the radius, temperature, and luminosity, which are key stellar parameters for studies of transit and habitability science. Here we present the results of new observations of Wolf~1061, known to host three super-Earths. Our observations from the Center for High Angular Resolution Astronomy (CHARA) interferometric array provide a direct stellar radius measurement of 0.32070.0088 ~R ⊙ , from which we calculate the effective temperature and luminosity using spectral energy distribution models. We obtained seven years of precise, automated photometry that reveals the correct stellar rotation period of 89.31.8 ~days, finds no evidence of photometric transits, and confirms the radial velocity signals are not due to stellar activity. Finally, our stellar properties are used to calculate the extent of the Habitable Zone for the Wolf~1061 system, for which the optimistic boundaries are 0.09--0.23~AU. Our simulations of the planetary orbital dynamics shows that the eccentricity of the Habitable Zone planet oscillates to values as high as ∼ 0.15 as it exchanges angular momentum with the other planets in the system.
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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

Post by Lazarus on 2nd January 2017, 9:54 am

Interesting, it looks like there's an updated orbital solution in the works which substantially changes the orbit of planet d.
The orbits of the planets were significantly updated by Astudillo-Defru et al. (2016b) using additional data from the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph. The orbital solutions largely agree with respect to the inner two planets, but the Astudillo-Defru et al. (2016b) solution finds an orbital period of the outer planet that is a factor of ∼3 larger than that found by Wright et al. (2016).
The authors also suggest that the eccentricity of planet c may help with the habitability:
However, it is worth noting that a zero eccentricity for planet c results in the orbit being entirely interior to the optimistic HZ. It is thus possible that planet c is more amenable to habitable conditions when near to peak eccentricity, since the planet moves slowly through the apastron passage in the HZ.
On the other hand, increasing the orbital eccentricity increases the orbit-averaged insolation (the proximity to the star at periastron more than compensates for the longer time spent at apastron), plus it leads to tidal heating. Taking the parameters of planet c from the Wright et al. solution (as far as I can tell, the Astudillo-Defru et al. paper is not yet available), and the tidal heating formula in this thread, assuming a radius of 1.5 R_Earth, I estimate that the energy dissipated by tidal heating ends up with a heat flux of roughly 9 W/m2, which is a few times higher than that of Io.
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Re: 3 planets around Wolf 1061 at 14 l.y (one in HZ)

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