# Caltech simulations: outer planet orbits may destabilize 1 billion years after Sun becomes white dwarf

- Published: 2026-11-13 23:33 UTC
- Section: Sky & Space › Astronomy
- Tags: Sun white dwarf, Solar System stability, outer planet orbits, Caltech simulations, Konstantin Batygin, red giant mass loss, solar recoil, The Astrophysical Journal Letters
- URL: https://realtech.media/news/rt-386ccd16a023bee729344a65_caltech_simulations_outer/

**Caltech researchers' computer models show that mass ejections from the dying Sun could nudge the star and disturb planetary orbits, far sooner than earlier estimates.**

![Caltech simulations: outer planet orbits may destabilize 1 billion years after Sun becomes white dwarf](https://realtech.media/media/2026/11/fa905523928f84ae.jpg)
*ESO, Wikimedia Commons, CC BY 4.0*

Astronomer Konstantin Batygin and colleagues at the California Institute of Technology (Caltech) ran 672 computer simulations of the future of the Solar System. According to cursorinfo.co.il, the calculations show that after the Sun becomes a white dwarf, the orbits of the outer planets may become unstable in about a billion years. Earlier estimates put such changes at 100 billion years [1]. The work is published in The Astrophysical Journal Letters.

## Mass ejections and recoil

As it ages, the Sun will become a red giant and then shed a significant part of its outer envelope. The authors suggest this may happen not as one continuous process but as about 4,600 separate ejections. By their calculations, each ejection will carry roughly one ten-thousandth of the star's original mass [1].

Each ejection produces a recoil that shifts the Sun slightly; the estimated speed of this motion reaches about seven meters per second. This previously underestimated factor may affect the gravitational balance of the planetary system. The researchers set the parameters for the calculations from observations of other stars [1].

## Simulation results

In 37 of 48 scenarios that included such ejections, planetary orbits crossed before the Sun finished becoming a white dwarf. In some models Saturn left the Solar System entirely, and in others Uranus and Neptune swapped places [1]. About three billion years after the white dwarf formed, orbits became unstable in almost 90% of the scenarios considered [1].

The authors stress that the result cannot yet be treated as a final forecast. Much depends on the actual mass of the ejections and on how uneven the shedding of the envelope will be. If the ejections turn out to be weak enough, more than 98% of the simulated planetary systems remain stable forever. There is as yet no direct evidence that the Sun will lose its envelope with the asymmetry needed for such consequences [1].

## Sources

1. [cursorinfo.co.il](https://cursorinfo.co.il/interest/solntse-obrechet-planety-na-haos-uchenye-obnaruzhili-neozhidannuyu-ugrozu)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-386ccd16a023bee729344a65_caltech_simulations_outer/