<p>The Jupiter mass planet <a href="https://phys.org/news/2020-03-large-telescope-exoplanet-iron.html" rel="noreferrer"><strong>WASP76b</strong></a> orbits its 1.5*Sunmass star at 0.03AU and is tidally locked. The day side heats to 2400C which vaporizes metals, including iron observed in its atmosphere. The balmy night side is only 1500C causing ferocious winds which carry the iron vapor from hot to cool side. There it condenses, falling as rain. </p>

<p><a href="https://i.sstatic.net/uE76t.jpg" rel="noreferrer"><img src="https://i.sstatic.net/uE76t.jpg" alt="enter image description here"></a></p>

<p>Could this redistribution of mass change how the planet faces its star, and what could make that happen? For example, if the winds blew only one direction (I don't know why this would occur) might that act as a small spin that tidal locking forces might try to neutralize?</p>

<p>This is a refugee question from Space Exploration.</p>

CC BY-SA 4.0
2020-03-12T04:21:02.500Z
@uhoh Someone who understands tidal locking ought to be able to explain whether a redistribution of mass would change what face a planet presented, whether this particular planet or not. This is physics in space so I considered Astronomy. I can move it if that is the right thing.
Pilothead
CC BY-SA 4.0
2020-03-12T04:40:41.117Z
I've changed my mind about "primarily opinion-based" and deleted my comments because probably conservation of angular momentum is all that's needed to generate a plausible answer; there's much known (or at least theorized) information about this particular planet.
uhoh
CC BY-SA 4.0
2020-03-12T05:01:06.057Z
at those temperatures I'd expect active tectonic currents (like on earth) in the planet's mantle, carrying the materials back to the cooler side and offsetting any mass change.
jwenting
CC BY-SA 4.0
2020-03-18T04:13:49.313Z
If the iron  rained out as soon as the vapor entered the dark side, an oblate spheroid would be formed, which might (I haven't done the math) be flipped 90 degrees by tidal forces. Also, if you make assumptions about the interior structure, something like this could happen: [Great tilt gave Mars a new face](https://www.sciencedaily.com/releases/2016/03/160302132609.htm).
Keith McClary
<exoplanet><tidal-locking>
Could iron rain upset tidally locked WASP76b?
Pilothead
# Could iron rain upset tidally locked WASP76b?

(Asked by: username_0 on 2020-03-12)

The Jupiter mass planet [**WASP76b**](https://phys.org/news/2020-03-large-telescope-exoplanet-iron.html) orbits its 1.5\*Sunmass star at 0.03AU and is tidally locked. The day side heats to 2400C which vaporizes metals, including iron observed in its atmosphere. The balmy night side is only 1500C causing ferocious winds which carry the iron vapor from hot to cool side. There it condenses, falling as rain.

[![enter image description here](https://i.sstatic.net/uE76t.jpg)](https://i.sstatic.net/uE76t.jpg)

Could this redistribution of mass change how the planet faces its star, and what could make that happen? For example, if the winds blew only one direction (I don't know why this would occur) might that act as a small spin that tidal locking forces might try to neutralize?

This is a refugee question from Space Exploration.

**Tags:** exoplanet, tidal-locking
> **Comments:**
> **username_0**: @uhoh Someone who understands tidal locking ought to be able to explain whether a redistribution of mass would change what face a planet presented, whether this particular planet or not. This is physics in space so I considered Astronomy. I can move it if that is the right thing.  
> **username_1**: I've changed my mind about "primarily opinion-based" and deleted my comments because probably conservation of angular momentum is all that's needed to generate a plausible answer; there's much known (or at least theorized) information about this particular planet.  
> **username_2**: at those temperatures I'd expect active tectonic currents (like on earth) in the planet's mantle, carrying the materials back to the cooler side and offsetting any mass change.  
> **username_3**: If the iron  rained out as soon as the vapor entered the dark side, an oblate spheroid would be formed, which might (I haven't done the math) be flipped 90 degrees by tidal forces. Also, if you make assumptions about the interior structure, something like this could happen: [Great tilt gave Mars a new face](https://www.sciencedaily.com/releases/2016/03/160302132609.htm).  

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## 0 answers

