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Nearby Exoplanets
JRehling
post Nov 15 2017, 04:17 PM
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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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JRehling
post Dec 6 2017, 04:40 PM
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A best-of-its-kind discovery: K2-18b (announced in 2015) is a transiting Super Earth 111 light years away. It orbits a red dwarf with a period of 32 days and has an equilibrium temperature very nearly equal to Earth's.

What's good: It transits! Studying the planet's atmosphere, therefore, can be done as the star's light passes through it, or by subtracting the planet's light from the system's as a whole when the star eclipses the planet. There is no need to resolve the planet, so the distance is not highly relevant to follow-up science.

This has also allowed an accurate measurement of mass and therefore density, and this reveals that the planet has a very earthlike density with 2.24x the radius and 8x the mass. This is itself a striking result as part of a new and growing survey of Super Earths, and the mystery of whether they are more like big Earths or little Neptunes. In most cases, we know the radius or the mass but not both.

What's bad: If we're looking for Earth analogues, the larger size may still mean that the atmosphere and climate are radically different from anything we've seen before. On the other hand, with red dwarf systems, there's a fear that flares could strip away an atmosphere and in this case, those two concerns potentially offset one another. Maybe a big planet with this high escape velocity could end up with an intact atmosphere that could even be more earthlike if a bit of it has been blasted away.

Add this to the short list of ones that we'll be watching closely over the next decade +.
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JRehling
post Feb 12 2018, 02:56 PM
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New clues to the density (and composition) of the Trappist-1 exoplanets:

https://www.jpl.nasa.gov/news/news.php?release=2018-022
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Posts in this topic
- JRehling   Nearby Exoplanets   Nov 15 2017, 04:17 PM
- - Ron Hobbs   Excellent! Thank you for the link to the artic...   Nov 15 2017, 09:26 PM
|- - JRehling   A quick look outward: Ross 128 is the 8th closest...   Nov 17 2017, 04:17 PM
- - JRehling   A best-of-its-kind discovery: K2-18b (announced in...   Dec 6 2017, 04:40 PM
|- - JRehling   New clues to the density (and composition) of the ...   Feb 12 2018, 02:56 PM
- - JRehling   An article in Nature announces the discovery of a ...   Nov 15 2018, 04:38 AM
- - Steve G   Bernard's star was the first star ever to have...   Nov 15 2018, 01:46 PM
|- - JRehling   Yeah, Steve, my public library had a book that fla...   Nov 15 2018, 06:24 PM
|- - JRehling   Various updates: Two planets, potentially habitab...   Jun 19 2019, 04:48 PM
- - ngunn   The Science Daily article contains these sentences...   Jun 21 2019, 08:17 AM
|- - JRehling   QUOTE (ngunn @ Jun 21 2019, 01:17 AM) the...   Jun 24 2019, 01:55 AM
|- - JRehling   Here's a fresh update on the specific and uniq...   Aug 8 2019, 02:27 PM
|- - dtolman   Not sure the best place to put this... but researc...   Aug 14 2019, 03:11 PM
|- - HSchirmer   QUOTE (dtolman @ Aug 14 2019, 04:11 PM) N...   Aug 15 2019, 04:31 PM
|- - JRehling   Proxima c, a candidate planet orbiting Proxima Cen...   Jan 16 2020, 08:03 PM
|- - HSchirmer   QUOTE (HSchirmer @ Aug 15 2019, 04:31 PM)...   Jul 9 2020, 12:38 PM
- - Hungry4info   The claim in the paper was a bit more nuanced than...   Jun 21 2019, 10:46 AM
- - ngunn   That's perfect, thanks! The figure shows ...   Jun 21 2019, 11:19 AM
- - Gladstoner   Interesting. Plus, for each Sol system planet, a...   Jun 21 2019, 11:39 PM
- - JRehling   Reanalysis of Kepler data finds one of the most pr...   Apr 16 2020, 07:02 PM
|- - JRehling   Astronomers using the VLT may have detected Proxim...   Apr 22 2020, 08:34 PM
|- - JRehling   The story of Proxima c has twisted and turned with...   Jun 7 2020, 04:25 AM
- - ngunn   Thanks for the interesting update and, in general,...   Jun 10 2020, 07:09 AM
|- - JRehling   Another nearby system with interesting potential: ...   Jul 6 2020, 08:02 PM
- - JRehling   We obviously have not yet begun to learn about the...   Dec 23 2020, 10:19 PM
|- - JRehling   We've been waiting well over a year to hear ab...   Feb 23 2021, 08:52 AM
- - Decepticon   A Earth-sized Moon sitting in orbit would be wishf...   Feb 23 2021, 09:53 PM
|- - JRehling   If I had to guess, the large natural moon of a ...   Feb 24 2021, 12:36 AM
|- - HSchirmer   QUOTE (Decepticon)A Earth-sized Moon sitting in or...   Feb 24 2021, 01:26 AM
|- - JRehling   This pushes the boundary of "nearby" a b...   Mar 14 2021, 06:20 AM
|- - JRehling   A new important discovery: Gliese 486 b, a small S...   Mar 23 2021, 06:19 PM
|- - JRehling   The initial set of TOIs (Tess Objects of Interest)...   Mar 30 2021, 08:37 PM
|- - JRehling   There's a long-running saga in progress about ...   Aug 19 2021, 02:29 PM
|- - JRehling   An exciting and new method for detecting candidate...   Oct 12 2021, 04:13 PM
- - Tom Tamlyn   The idea of living in a solar system with titanic ...   Aug 19 2021, 05:24 PM
|- - HSchirmer   QUOTE (Tom Tamlyn @ Aug 19 2021, 05:24 PM...   Aug 19 2021, 08:47 PM
- - Hungry4info   QUOTE ("JRehling")I haven't found ac...   Oct 12 2021, 11:17 PM
|- - JRehling   The Perger, et al paper that finds no evidence for...   Oct 13 2021, 05:26 AM
|- - dtolman   3rd planet potentially found around Proxima Centau...   Feb 10 2022, 04:14 PM
- - g4ayu   Planetary bodies observed in habitable zone of dea...   Feb 11 2022, 07:59 AM
- - StargazeInWonder   TESS finds a star with two hot transiting terrestr...   Jun 18 2022, 07:06 PM
- - StargazeInWonder   TESS has found a system with two planets somewhat ...   Sep 20 2022, 06:19 AM
- - StargazeInWonder   Not a typo: TESS has discovered a second candidate...   Jan 13 2023, 02:54 PM


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