can a star orbit a planet

Introduction

The question of whether a star can orbit a planet is intriguing and challenges our understanding of celestial mechanics. Typically, we observe planets orbiting stars due to the significant mass difference between the two. However, exploring the dynamics of such systems can provide insights into the gravitational interactions and formation processes of celestial bodies.

Key Insights

Planetary Systems Around Stars:
- Numerous studies have confirmed the existence of planets orbiting various types of stars, including main-sequence stars, red giants, and neutron stars .
- Planets have been found in diverse orbits, ranging from very close to their stars to more distant, stable orbits .
Gravitational Dynamics:
- The gravitational influence of a planet on a star is typically minimal due to the significant mass difference. However, in systems with massive planets (e.g., Jupiter-sized or larger), the star can exhibit a detectable wobble or reflex motion .
- This reflex motion is a result of the star and planet orbiting a common center of mass, which is usually located inside the star due to its larger mass .
Special Cases and Theoretical Considerations:
- In systems with very low-mass stars and relatively massive planets, the dynamics can be more complex. For example, a large planet orbiting a very low-mass star can challenge traditional planet formation theories and result in significant gravitational interactions.
- The concept of a star orbiting a planet would require the planet to be extraordinarily massive, potentially comparable to a brown dwarf or even a small star, which blurs the line between planets and stars .

Conclusion

While traditional celestial mechanics dictate that planets orbit stars due to the significant mass difference, the gravitational interactions in systems with massive planets can cause detectable reflex motions in stars. The idea of a star orbiting a planet is theoretically possible but would require the planet to be exceptionally massive, akin to a brown dwarf or small star. Thus, in practical terms, stars and planets typically orbit a common center of mass, with the star's motion being much less pronounced due to its larger mass.

Can a star orbit a planet

Summary

Consensus Meter

Introduction

Key Insights

Conclusion

Sources and full results

Three planets transiting the evolved star EPIC 249893012: a hot 8.8-M⊕ super-Earth and two warm 14.7 and 10.2-M⊕ sub-Neptunes

This study discovers a new planetary system with one super-Earth and two sub-Neptunes orbiting an evolved star, offering potential for further study on dynamical aspects.

Planets Orbiting Other Suns

Planets orbiting other stars are confirmed, with 5% of main-sequence stars harboring companions within 3 AU, suggesting diverse systems and the need for special initial conditions for stable coplanar orbits.

A giant planet orbiting the ‘extreme horizontal branch’ star V 391 Pegasi

This discovery of a planet orbiting a post-red-giant star shows that planets with orbital distances less than 2 au can survive the red-giant expansion of their parent stars.

Confirmation of Earth-Mass Planets Orbiting the Millisecond Pulsar PSR B1257 + 12

The discovery of two Earth-mass planets orbiting a rapidly spinning neutron star, PSR B1257+12, constitutes the first planetary system around a star other than the sun.

Hints of a Planet Orbiting Sunlike Star

Swiss astronomers believe they have found the first evidence for a planet orbiting a sunlike star, detecting an apparent wobble in a star just outside the Great Square of Pegasus.

A Transiting Planet of a Sun-like Star

The planet XO-1b transits an 11th magnitude, G1 V star in the constellation Corona Borealis, with a mass 0.90 0.07MJ and an orbital period of 3.941534 0.000027 days.

A PLANET IN AN 840 DAY ORBIT AROUND A KEPLER MAIN-SEQUENCE A STAR FOUND FROM PHASE MODULATION OF ITS PULSATIONS

A 12 M Jup planet orbiting in or near the habitable zone of a main-sequence A star has been discovered using orbital motion, supporting the idea that A stars harbor high-mass planets in wide orbits.

A low-mass star with a large-mass planet

A planet with a mass of 13.2 Earth masses has been discovered orbiting a very low-mass star, challenging theories of planet formation and demonstrating the existence of massive planets orbiting low-mass stars.

An extrasolar planet that transits the disk of its parent star

A 0.9 Jupiter mass object in an orbit of 0.023 au from its star causes periodic dimming of starlight, suggesting it may be a transiting planet.

Three planets transiting the evolved star EPIC 249893012: a hot 8.8-M⊕ super-Earth and two warm 14.7 and 10.2-M⊕ sub-Neptunes

This study discovered a new planetary system with a hot 8.8-M super-Earth and two warm sub-Neptunes orbiting EPIC 249893012, a G8-IV-V evolved star.

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