Big find! Scientists spot giant alien planet orbiting close to dead star's corpse

rod

Oct 22, 2019
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The space.com report makes it clear this is a planet candidate, there will be follow ups to confirm. I note this in the report.

"It's therefore safe to say that WD 1856 b didn't form at its current location; the object would never have survived WD 1856's red-giant phase. Indeed, the study team's calculations suggest that the candidate planet must have been born about 50 times farther away from the star than its current location, then migrated in. "We've known for a long time that after white dwarfs are born, distant small objects such as asteroids and comets can scatter inward towards these stars. They're usually pulled apart by a white dwarf's strong gravity and turn into a debris disk," study coauthor Siyi Xu, an assistant astronomer at the international Gemini Observatory in Hawaii, said in the same statement. "That's why I was so excited when Andrew told me about this system," Xu said. "We've seen hints that planets could scatter inward, too, but this appears to be the first time we've seen a planet that made the whole journey intact." It's unclear what gave WD 1856 b its inward push. Possibilities include nudges from the other two stars in the WD 1856 system and a brief interaction with an intruding "rogue star," wrote team members in the new study, which was published online today (Sept. 16) in the journal Nature."

if confirmed the exoplanet will be challenging to explain like the report shows, migrating inwards by some 50x from its potential present location at the WD host star. Other reports indicate the candidate could be at least 14 Jupiter masses, A giant planet candidate transiting a white dwarf, https://www.nature.com/articles/s41586-020-2713-y

I plan to monitor further reports on this very interesting exoplanet candidate.
 
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Reactions: Helio
Jun 1, 2020
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I'm curious with what makes it so surprising to astronomers? The phase prior to becoming a WD had massive gas outflows that would, I think, cause serious migration of all the objects that were orbiting. If the massive ones were far enough out -- the article suggests 50x what it is now -- then it would survive the migration since the mass flows eventually ended, as it's now a WD. They mention gravity destroys such objects, but a WD is much weaker in gravity than when all the objects orbited normally. So are they implying that the migration creates huge eccentricity such that their close approach is within the Roche limit? That seems unlikely.
 
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May 30, 2020
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As the white dwarf is formed, the red giant sheds it's outer layers, wonder what modelling would show if a deep orbit gas giant could absorb a lot of this gas and spiral inwards as a result.

Or even more extreme, the blasted off gas forms a new planet
 

rod

Oct 22, 2019
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Helio et al. This site is now reporting the nearly 14 Jupiter mass exoplanet, https://exoplanetarchive.ipac.caltech.edu/overview/WD 1856+534

The exoplanet is listed at 13.8 Jupiter mass, radius= 0.928 Jupiter so the mean density ~ 21 g cm^-3, orbital period near 1.4 days and WD host star 0.52 solar masses. *Big find!* I am not so sure about this :) There are other WD listed as confirmed with exoplanets that report even more masses. Example, WD 0137-349 b, 56 Jupiter masses with period < 1 day and WD star 0.39 solar masses. Another example, WD 0837+185 B, 30 Jupiter masses, orbital period < 1 day, WD star 0.798 solar masses.


I am enjoying monitoring the reporting on this WD exoplanet, having too much fun :)
 

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