Astronomers Spot a High-Speed Star That May Carry a Planet With It

A celestial object, possibly a small star with a massive exoplanet, has been observed moving through the Milky Way at an extraordinary speed of over 1.2 million mph. The discovery has led researchers to believe that this could be the fastest planetary system ever detected. The object was first identified in 2011 through microlensing, a technique where light is bent by gravitational fields. A new study has now linked this object to a recently identified star, though uncertainties remain about its exact nature and velocity.

Potential Star and Exoplanet System Analysed

According to a study published in The Astronomical Journal, the newly observed star is estimated to be around one-fifth the mass of the Sun and located approximately 24,000 light-years away in the galactic bulge. If it is the same object from the 2011 microlensing event, calculations suggest it is moving at an extreme speed. The presence of an exoplanet has not been confirmed, but based on mass estimates, researchers suggest it could be a «super-Neptune» orbiting the star at a distance comparable to Venus or Earth in the Solar System.

Possibility of Escape from the Milky Way

If the speed of the stellar object exceeds 1.3 million mph, scientists suggest it may eventually leave the Milky Way, potentially carrying its exoplanet into intergalactic space. Sean Terry, postdoctoral researcher at the University of Maryland and NASA’s Goddard Space Flight Center, stated to NASA that if confirmed, it would be the first planet ever detected orbiting a hypervelocity star. However, he emphasised that further observations are necessary to verify its identity and trajectory.

Uncertainties and Alternative Theories

David Bennett, senior research scientist at the University of Maryland, told NASA that additional observations are needed to confirm whether this is the same object spotted in 2011. The research team plans to monitor the star’s movement over the next year to verify its trajectory. Another possible explanation is that the 2011 observation detected a rogue planet with an exomoon rather than a star-exoplanet system. Aparna Bhattacharya, research scientist at the University of Maryland, explained to NASA that if the object does not move as expected, the rogue planet hypothesis may be favoured.