Sunday, March 5, 2023

3901 - FORBIDEN PLANETS - too big for their sun?

 

3901  -  FORBIDEN  PLANETS  -  too big for their sun?    Massive 'forbidden planet' orbits a strangely tiny star only 4 times its size  The discovery could challenge our theories of how gas giants like Jupiter form.

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------------  3901  -   FORBIDEN  PLANETS  -  too big for their sun?

-    Massive 'forbidden planet' orbits a strangely tiny star only 4 times its size  The discovery could challenge our theories of how gas giants like Jupiter form.

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-    Astronomers have discovered an unusual planetary system consisting of a Jupiter-sized planet orbiting a tiny star that is only four times the size of the solar system gas giant. This could challenge theories of how gas giant planets form.

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-    The exoplanet orbits a red dwarf star designated “TOI 5205” that is much cooler and smaller than the sun. The small size and relatively cool temperatures of these M-dwarf stars, the most common type of stellar body in the Milky Way, make them redder than the sun.

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-    The discovery of this exoplanet using NASA's “Transiting Exoplanet Survey Satellite” (TESS) telescope challenges that concept. The planet was confirmed and characterized by the team using various ground-based telescopes and instruments.

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-    The host star is just about four times the size of Jupiter, yet it has somehow managed to form a Jupiter-sized planet.  Though gas giants have been discovered around M dwarf stars before, none of them have been discovered orbiting such a low mass example of this class of star.

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-    Planets are created in spinning discs of gas and dust called "protoplanetary discs" that surround young stars. This material is the remains of the same matter that collapsed to birth its central star. When dense patches collapse under their own gravity planet cores are born and they then collect more material.

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-    Current planet formation models suggest that to birth a gas giant it takes material equivalent to 10 times the mass of Earth. This first forms a rocky core and this core goes on to accumulate gas to form the disc to grow a giant planet. This process has to occur quickly.

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-    In the beginning, if there isn't enough rocky material in the disk to form the initial core, then one cannot form a gas giant planet. And at the end, if the disk evaporates away before the massive core is formed, then one cannot form a gas giant planet.

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-   And yet TOI-5205b formed despite these guardrails.  Based on our nominal current understanding of planet formation, TOI-5205b should not exist; it is a 'forbidden' planet."

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-    To picture how unbalanced this system is to planetary systems that astronomers expect, imagine our star the sun squashed down to the size of a grapefruit. That size reduction would mean the largest gas giant in our solar system, Jupiter, would be about the size of a garden pea.

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-    The TOI-5205 system is more like a pea orbiting a lemon.

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-       The size disparity in the size is so great that when TESS used the drop in light caused by a planet as it passes in front of its star, known as the transit method, that dip in light was 7% of the star's total light output.

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-    That makes the dimming of TOI-5205 by this Jupiter-sized exoplanet the largest known drop in light caused by an exoplanet transit.   This extreme dip in light or technically, "large transit depth,".

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-  Observations with the James Webb Space Teleacope could help determine the composition of TOI-5205 b's atmosphere and may shed light on the processes that birthed this "forbidden" planet.

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-    The total dust and gas for a postulated protoplanetary disc around a

0.392 solar mass red dwarf could be 1.305136E+03 earth masses. The      1.08 exoplanet is about 343.2456  earth masses.

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-    Are we absolutely certain that it is a "rocky" gas giant? Why not a binary star that has failed to form because of a lack of total mass?

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-   With the number of stars out there, even wildly improbably configurations are going to exist in abundance. Maybe this system only existed because of a sequence of unique gravitation interactions.

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-   Theories may be too rigid, but not entirely wrong. Also, we must take great care in exoplanet analysis because the data is skewed towards what is easiest to detect...

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                   March 5, 2023     FORBIDEN  PLANETS  -  too big for their sun?       3901                                                                                                                        

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--------------------- ---  Sunday, March 5, 2023  ---------------------------

 

 

 

 

         

 

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