# Orbital distance increase during the white dwarf phase of the Sun

• I
• Dreksler
In summary, the conversation discusses the estimated mass loss of the Sun during its white dwarf phase and its potential impact on the orbit of Pluto. The calculation process involves using an equation relating orbital speed to radius, derived from the gravitational force and centripetal force, and considering conservation of angular momentum. It is uncertain exactly how much the Sun's mass will decrease, but assuming a 50% decrease, Pluto's orbit is expected to expand due to a lower gravitational pull from the Sun.
Dreksler
TL;DR Summary
Want to know as to how to calculate orbital distance of bodies in the Solar system during the white dwarf phase of the Sun.
Some estimates through calculating the sun mass loss and increase in mass loss say that the white dwarf phase of the Sun will have roughly about 50% the current mass of the Sun (not sure about it). Whatever the actual mass loss is going to be, assuming that the 50% mass loss is true, where would that approximately put the orbit of let's say Pluto, how much outward will it expand due to a lower gravitational pull from the Sun, and what is the calculation process?

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You have an equation relating orbital speed to radius (derived from gravitational force = "centripetal force").
Then use conservation of angular momentum.

Last edited:
Vanadium 50 and Dreksler

## 1. What is the "white dwarf phase" of the Sun?

The white dwarf phase is the final stage of a star's life cycle, in which it has exhausted all of its nuclear fuel and has collapsed into a small, extremely dense object. This phase occurs after the red giant phase, when the outer layers of the star have been expelled and the remaining core is left behind.

## 2. How does the orbital distance of a planet change during the white dwarf phase?

During the white dwarf phase, the Sun's mass decreases significantly and its gravitational pull weakens. This causes the orbits of planets to expand, as they are no longer held as tightly by the Sun's gravity.

## 3. What factors influence the amount of orbital distance increase during the white dwarf phase?

The amount of orbital distance increase during the white dwarf phase depends on the mass of the star, the mass and distance of the planet, and the distance of the planet from the star during the red giant phase. Generally, the more massive the star and the closer the planet was to the star during the red giant phase, the larger the increase in orbital distance will be.

## 4. Will the Earth's orbit be affected by the Sun's transition into a white dwarf?

Yes, the Earth's orbit will be affected by the Sun's transition into a white dwarf. However, it is estimated that the Earth's orbit will only expand by about 1.5% during the Sun's white dwarf phase, which is not enough to significantly impact life on Earth.

## 5. Is there a maximum limit to how much the orbital distance can increase during the white dwarf phase?

Yes, there is a maximum limit to how much the orbital distance can increase during the white dwarf phase. This limit is determined by the mass of the star and the initial distance of the planet from the star during the red giant phase. If the planet was too close to the star during the red giant phase, it may be completely ejected from the system during the white dwarf phase, resulting in a significant increase in orbital distance.

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