Tidally Locked Planets: How Close to the Star?

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Thread starter AstroCody
Start date Mar 31, 2016
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Exoplanet Planet Planets Star tidally locked

In summary, a tidally locked planet is a celestial body with one side always facing its star and the other in constant darkness. It is difficult for life to exist on such a planet due to extreme temperature differences, but habitable conditions may exist in the "twilight zone." The distance at which a planet becomes tidally locked varies, and it can lead to strong winds, affect the development of organisms, and leave the planet vulnerable to solar winds and radiation. In our solar system, the Moon and Mercury are considered tidally locked.

Mar 31, 2016

AstroCody

How close must a planet be to its parent star in order for it to be tidally locked?

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Mar 31, 2016

Borg

Science Advisor

Gold Member

Tidal locking isn't just determined by position. It takes time for bodies to become locked and it is highly dependant upon the size of the bodies and initial rotations. So I don't think that there is a good general answer to this.

Mar 31, 2016

AstroCody

Thanks for the answer and the link, it was very helpful.

Related to Tidally Locked Planets: How Close to the Star?

1. What is a tidally locked planet?

A tidally locked planet is a celestial body that has one side permanently facing its star, while the other side is in constant darkness. This occurs when the planet's rotation rate is synchronized with its orbit around the star.

2. Can a tidally locked planet support life?

It is difficult for a tidally locked planet to support life as the extreme temperature differences between the two sides can make it challenging for organisms to survive. However, there is a possibility that habitable conditions may exist in the narrow band between the hot and cold sides, known as the "twilight zone."

3. How close can a planet be to its star and still be tidally locked?

The distance at which a planet becomes tidally locked depends on several factors, including the size and mass of the planet and its star. Generally, planets that are closer to their stars have a higher chance of becoming tidally locked. However, the exact distance varies and can range from a few million kilometers to a few hundred million kilometers.

4. What are the potential consequences of a tidally locked planet?

The extreme temperature differences on a tidally locked planet can lead to strong winds and weather patterns, making it difficult for life to exist. The lack of a day-night cycle may also affect the development of organisms and their circadian rhythms. Additionally, the lack of a magnetic field due to the planet's slow rotation can leave it vulnerable to solar winds and radiation.

5. Are there any known tidally locked planets in our solar system?

Yes, the Moon is tidally locked to Earth, meaning it always shows the same face to our planet. In our solar system, Mercury is also in a 3:2 spin-orbit resonance, where it rotates three times for every two orbits around the Sun. However, it is not considered a true tidally locked planet as it has a slight axial tilt.