[HN Gopher] Astronomers uncover largest group of rogue planets yet
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Astronomers uncover largest group of rogue planets yet
Author : LinuxBender
Score : 47 points
Date : 2021-12-31 16:22 UTC (1 days ago)
(HTM) web link (www.sciencedaily.com)
(TXT) w3m dump (www.sciencedaily.com)
| addaon wrote:
| Do these form like stars (as the primary mass in a cloud
| collapse?), or do they form like solar planets (secondary masses
| around a star) and get ejected? If the former, is there any
| mechanism for ejecting light elements to produce something like a
| terrestrial planet or are these inherently gas planets?
| stevenpetryk wrote:
| From the article:
|
| > Some scientists believe rogue planets can form from the
| collapse of a gas cloud that is too small to lead to the
| formation of a star, or that they could have been kicked out
| from their parent system. But which mechanism is more likely
| remains unknown.
| addaon wrote:
| Not sure how I missed this, thanks!
|
| Am I correct that the latter mechanism can lead to a wider
| variety of planet compositions, since you have the wind off
| the forming star to blow off lightweight layers depending on
| how close to the star formation happens?
| JoeAltmaier wrote:
| I imagine most planets might be rogue. Stellar formation is
| incredibly energetic and violent. That any planets remain in
| stable arrangements is amazing.
| akiselev wrote:
| I'm kind of burned out on exoplanet discoveries since they're a
| dime a dozen nowadays but this title caught my eye because I've
| been rewatching Star Trek DS9 recently. The antagonist in the
| latter half of the series is the Dominion empire which is
| unilaterally controlled by a race of hivemind-y shapeshifters
| called the Changelings. The only time we get to see most of their
| species is on their home world, a rogue planet somewhere in the
| gamma quadrant.
|
| I've been fascinated by the idea of detecting rogue planets ever
| since and it's incredible they found so many. Unfortunately, it
| looks like their detection method might not be useful for older
| (billion+) or rocky planets (from the footnote):
|
| _> The exact number of rogue planets found by the team is hard
| to pin down because the observations don 't allow the researchers
| to measure the masses of the probed objects. Objects with masses
| higher than about 13 times the mass of Jupiter are most likely
| not planets, so they cannot be included in the count. However,
| since the team didn't have values for the mass, they had to rely
| on studying the planets' brightness to provide an upper limit to
| the number of rogue planets observed. The brightness is, in turn,
| related to the age of the planets themselves, as the older the
| planet, the longer it has been cooling down and reducing in
| brightness. If the studied region is old, then the brightest
| objects in the sample are likely above 13 Jupiter masses, and
| below if the region is on the younger side. Given the uncertainty
| in the age of the study region, this method gives a rogue planet
| count of between 70 and 170._
|
| That said, this is exciting news!
|
| _> The study suggests there could be many more of these elusive,
| starless planets that we have yet to discover. "There could be
| several billions of these free-floating giant planets roaming
| freely in the Milky Way without a host star," Bouy explains._
| Jeff_Brown wrote:
| Above 13 Jupiter masses would it have to be a burned out star?
| TheOtherHobbes wrote:
| Brown dwarf? Some sputtering early attempts at fusion, but
| not enough to become self-sustaining.
|
| 13 Mj is on the low side of the definition. It's not a
| definitive number and goes as high as 80 Mj, depending who
| you ask.
| TaylorAlexander wrote:
| I'm imagining at least one rogue planet out there (they said they
| could be billions) was happily orbiting a star for billions of
| years, life formed, even relatively intelligent life, and then
| another rogue planet fell in to the solar system and passed right
| by the first planet in such a way as to eject it from the solar
| system without hitting it, and all this life on the planet
| suddenly loses daylight as their planet flies off in to deep
| space. And now their ancient civilization is frozen in time,
| adrift in deep space.
| rd07 wrote:
| This could be a scenario for a doomsday movie. On another note,
| I wonder if our solar system has been visited by such rogue
| planet in the past.
| wumpus wrote:
| https://en.wikipedia.org/wiki/A_Pail_of_Air
|
| full text: https://www.gutenberg.org/ebooks/51461
| TaylorAlexander wrote:
| wow very cool thank you!
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