IPB

Welcome Guest ( Log In | Register )

2 Pages V  < 1 2  
Reply to this topicStart new topic
Nearby Exoplanets
dtolman
post Aug 14 2019, 03:11 PM
Post #16


Junior Member
**

Group: Members
Posts: 97
Joined: 20-April 05
Member No.: 291



Not sure the best place to put this... but researchers have used DSCOVR/EPIC data to create a simulated single image of the Earth - then used the light curve to create a two dimensional map of the Earth that manages to capture the rough shape of North America, Eurasia, Africa, and Australia/Antarctica.

A similar technique could be used for any exoplanet with static albedo features (such as oceans or continents).
Go to the top of the page
 
+Quote Post
HSchirmer
post Aug 15 2019, 04:31 PM
Post #17


Member
***

Group: Members
Posts: 485
Joined: 24-July 15
Member No.: 7619



QUOTE (dtolman @ Aug 14 2019, 04:11 PM) *
Not sure the best place to put this... but researchers have used DSCOVR/EPIC data to create a simulated single image of the Earth - then used the light curve to create a two dimensional map of the Earth that manages to capture the rough shape of North America, Eurasia, Africa, and Australia/Antarctica.

A similar technique could be used for any exoplanet with static albedo features (such as oceans or continents).



Interesting article about locating a telescope near the Lagrange point, which would use diffraction through the outer atmosphere to create an image with up to 45,000 amplification.

QUOTE

Go to the top of the page
 
+Quote Post
JRehling
post Jan 16 2020, 08:03 PM
Post #18


Senior Member
****

Group: Members
Posts: 2249
Joined: 20-April 05
Member No.: 321



Proxima c, a candidate planet orbiting Proxima Centauri at 1.5 AU.

https://www.scientificamerican.com/article/...e-of-proxima-c/
Go to the top of the page
 
+Quote Post
JRehling
post Apr 16 2020, 07:02 PM
Post #19


Senior Member
****

Group: Members
Posts: 2249
Joined: 20-April 05
Member No.: 321



Reanalysis of Kepler data finds one of the most promising earthlike candidate exoplanets yet:

https://www.nasa.gov/press-release/earth-si...asa-kepler-data

Key takeaways, in my opinion:

Kepler 1649-c is the second planet found in its system and the first has previously been called a candidate Venus-like planet.

The mass and density of the planet have not yet been measured.

The host star is a red dwarf. It has not been established yet how prone this star is to flares.

This is unusually close for a Kepler discovery

For a reasonably stringent definition of "earthlike" in terms of size and thermal radiation, this is only the fourth star found to host a transiting earthlike candidate. The other three are Kepler 186, TOI 700, and TRAPPIST-1, which hosts about two such candidates.

So, we have about five such candidates that transit their star, and these will all be outstanding candidates for examination with JWST, to see if we can assess their color, albedo, spectrum, temperature, and atmospheric composition. Of these, only one, Kepler 186f, does not orbit a red dwarf, and is therefore not tidally locked. That may be important for habitability, and also would allow us to determine a light curve and produce a low resolution map.
Go to the top of the page
 
+Quote Post
JRehling
post Apr 22 2020, 08:34 PM
Post #20


Senior Member
****

Group: Members
Posts: 2249
Joined: 20-April 05
Member No.: 321



Astronomers using the VLT may have detected Proxima c optically.

This result still lurks on the boundary between a suspected detection and an actual detection, and I think if you read the literature fairly, it remains possible that Proxima c doesn't even exist. Multiple lines of evidence (each individually not compelling) pointing to the same entity start to add up to some real evidence, but there's no formal way to assess the significance of an unknown signal.

Meanwhile a VLT campaign aimed at Alpha Centauri A and B last year has still not released its results.

The key takeaway is that optical studies of nearby exoplanets have not yet begun, but we're knocking on the door.

https://www.scientificamerican.com/article/...net-proxima-c1/
Go to the top of the page
 
+Quote Post
JRehling
post Jun 7 2020, 04:25 AM
Post #21


Senior Member
****

Group: Members
Posts: 2249
Joined: 20-April 05
Member No.: 321



The story of Proxima c has twisted and turned with a fourth result pointing to its existence and apparent confirmation. This is a unique case in all of exoplanet science as the evidence for its existence combines radial velocity, direct imaging, and astrometry (side-to-side motion).

http://astrobiology.com/2020/06/25-year-ol...centauri-c.html

Furthermore, careful studies of Proxima b have refined (and lowered) its estimated mass, and furthermore provided evidence of Proxima d: a planet with a mass of about 0.3 ME and an orbital period of 5.15 days.

All told, Proxima Centauri now has a possible "Mercury" to go along with its "Earth" and "Neptune." Proxima c (the Neptune) remains the best, possibly unsurpassable, case scenario for imaging a nearby exoplanet as the technologies become available.

There has still been no publication regarding VLT searches for possible planets orbiting Alpha Centauri A and B that took place at this time last year. Originally, the team was hopeful that they would have something to say, one way or the other, by October.
Go to the top of the page
 
+Quote Post
ngunn
post Jun 10 2020, 07:09 AM
Post #22


Senior Member
****

Group: Members
Posts: 3495
Joined: 4-November 05
From: North Wales
Member No.: 542



Thanks for the interesting update and, in general, for keeping this thread refreshed with new information and ideas. I am always reminded as the curtain slowly lifts of the limitations imposed by observational selection and wonder about the remaining unseen planets in this and other systems.
Go to the top of the page
 
+Quote Post
JRehling
post Jul 6 2020, 08:02 PM
Post #23


Senior Member
****

Group: Members
Posts: 2249
Joined: 20-April 05
Member No.: 321



Another nearby system with interesting potential: Last month, the discovery of two warm/hot Super Earths around Lacaille 9352 (Gliese 887) was announced. This is actually the brightest red dwarf in the sky (or nearly so) at 10.7 light years away, and is near the boundary of classification as a K star rather than M. This alone is a notable discovery. What might be more interesting is the additional indication of a third planet with an orbital period of 51 days, because such a planet, if real, could be an earth-sized planet in the habitable zone. Moreover, such a planet might turn out to be outside the grip of tidal locking. I'm putting the cart before the horse with all those "if"s but the significance is that tidal locking might turn out to be a factor restricting habitability, and we know of very few earth-sized planets in habitable zones that aren't likely to be tidally locked, and we don't know of any that are this nearby. (Of course, we have yet to establish the rotation of any earth-sized exoplanets, but dynamical factors strongly imply this for many cases.)

I think we should be on the lookout for confirmation and followup in case Gliese 887 d exists. This, along with Alpha Centauri A and B, Tau Ceti, and Epsilon Eridani, offer five nearby possibilities for non-tidally locked earthlike planets that we will be able to observe directly. As yet, we have zero discoveries, so this mere hint of one is already something to pique the intrigue.
Go to the top of the page
 
+Quote Post
HSchirmer
post Jul 9 2020, 12:38 PM
Post #24


Member
***

Group: Members
Posts: 485
Joined: 24-July 15
Member No.: 7619



QUOTE (HSchirmer @ Aug 15 2019, 04:31 PM) *
Interesting article about locating a telescope near the Lagrange point, which would use diffraction through the outer atmosphere to create an image with up to 45,000 amplification.


I like the naming convention - Terrascope for Earth as lens, that would make the FOCAL / solar Einstein ring scope a Solscope?

Can't wait for the figures for the Jovascope...
Go to the top of the page
 
+Quote Post

2 Pages V  < 1 2
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 16th July 2020 - 04:43 PM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.