Nearby Exoplanets |
Nearby Exoplanets |
Nov 15 2017, 04:17 PM
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#1
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
There have been a few topics in recent years pertaining to exoplanets found circling nearby red dwarfs, particularly Proxima Centauri and Trappist-1. There's a new one to report, and I thought I'd give the topic a more general scope rather than specific to this one.
The star in question is Ross 128, and the planet's solar flux is between that of Earth and Venus. There's a good chance that this is potentially the most "habitable" exoplanet yet found, and is happily quite close (13th closest system), so that telescopes will be able to separate the light of the planet from that of the star. This is a circumstance that only a few nearby stars will permit in the foreseeable future, so Ross 128 is likely to figure large in our exoplanet studies over the next century. https://www.eso.org/public/archives/release...36/eso1736a.pdf |
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Feb 23 2021, 09:53 PM
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#2
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Senior Member Group: Members Posts: 1276 Joined: 25-November 04 Member No.: 114 |
A Earth-sized Moon sitting in orbit would be wishful thinking.
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Feb 24 2021, 12:36 AM
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#3
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
If I had to guess, the large natural moon of a "Neptune" inside the ice line would be about the mass of Titania minus its ice mass, so more like Vesta than Earth, but I'm extrapolating from very low n!
For the hope of a close Earth analogue orbiting Alpha Centauri A, I think we have a better chance that this will be a false detection and a yet-undetected terrestrial planet will coincidentally be in its place. Or, that this planet is real and an earth-sized terrestrial planet will be outside of it, still in the habitable zone. If this is a Neptune where we think it is, it would stand a good chance of holding this distinction: The exoplanet with the largest apparent diameter, and thus, likely the first we will ever image with detail… whenever appropriately powerful instruments come about. |
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Feb 24 2021, 01:26 AM
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#4
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
QUOTE (Decepticon) A Earth-sized Moon sitting in orbit would be wishful thinking. Eh, not entirely out of the realm of possibilities, but I guess they'd be more likely to be water-worlds? If I had to guess, the large natural moon of a "Neptune" inside the ice line would be about the mass of Titania minus its ice mass, so more like Vesta than Earth, but I'm extrapolating from very low n! I will be interesting either way, especially because this may be our first glimpse of an ice giant with the primordial moon system intact. Given that in our solar system "we can't have nice things" and both our ice giants are a bit damaged..... |
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Mar 14 2021, 06:20 AM
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#5
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
This pushes the boundary of "nearby" a bit, but TESS has found a five-planet transiting system orbiting a sunlike star.
https://en.wikipedia.org/wiki/HD_108236 By the nature of TESS, it is a given that any of its discoveries are in short-period orbits, so while the solar system's fifth planet has an orbital period of 12 years, this system's fifth planet has an orbital period of under 30 days. The estimated densities of the two inner planets are rather similar to Earth while the three outer planets have more Neptune-like densities. High temperatures should make these planets rather unlike Earth but these are still of great interest because, as transiting planets only 211 LY away, these are still good candidates for follow-on study, because the apparent magnitude of the star (9.24) allows for good signal to noise ratio. For comparison, TRAPPIST-1, though much closer, is a red dwarf, and appears much dimmer. HD 108236's system may permit some breakthroughs in our understanding of the evolution of super Earths. Studies to characterize these planets will certainly book some time on JWST and terrestrial telescopes. |
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