Scientists found a runaway star that was ejected by a supernova. Credit: NASA/GSFC/Dana Bery

Rogue Star Spotted Flying Across Our Galaxy at 2 Million Mph

Astronomers suggested that only a celestial body that survived a powerful cosmic catastrophe could develop such a speed.


An international team of astronomers has received new data on a mysterious object, first seen in 2017 and dubbed a “runaway star”. This object crossed the Milky Way at a speed of 3.2 million kilometers per hour, and it is moving, as the researchers say, in the wrong direction.

Everything you need to know about the “runaway star” moving at 2 million miles per hour

Discovery and name

The discovery of the mysterious object made a splash in the world of astronomy when it was revealed in 2017. Initially, scientists classified it as a star and gave it the official name LP 40-365.


Speed and direction

The subsequent detailed study literally stunned the specialists. It was found that the object is moving at an incredible speed of about 3.2 million km / h – this is about four times faster than the speed of movement of our Sun in orbit around the center of the galaxy. Moreover, it turned out that the object is flying in the “wrong” direction – against the direction in which most stars move around the center of our galaxy.

Different than the typical stars in the Milky Way

Another anomaly that was identified was that this object is composed of a completely different material compared to the rest of the stars in the Milky Way. It is saturated with heavy “metallic” atoms, while other stars are dominated by light chemical elements.

A “Runaway Star”

The incredible speed of movement indicates that the object is seeking to leave the confines of our galaxy. Based on this fact, astronomers in their new study suggested that only a celestial body that survived a powerful cosmic catastrophe could develop such a speed.


Suspicion fell on a supernova explosion, as a result of which a powerful burst of energy could give an impulse to “runaway star” LP 40-365. But is this object part of an exploding star, or was it a partner star thrown into space by a powerful shock wave?


New analysis

A new analysis of the data obtained back in 2017 made it possible to give preference to the hypothesis that LP 40-365 is, in fact, space debris. That is, this is a splinter of a white dwarf that managed to survive after an event about which one can only guess so far.

A pair of white dwarfs

Astronomers concluded that this star was part of a paired star system about five million years ago – a pair of white dwarfs. The fate of such small stars, similar to the Sun, is typical – over time, one star takes away so much mass and energy from its partner that it explodes. Such explosions are so powerful that old elements combine their nuclei into completely new elements.

Artist's impression of a white dwarf in a binary system whose mass is being taken away by its partner. Credit: NASA/CXC/M. Weiss
Artist’s impression of a white dwarf in a binary system whose mass is being taken away by its partner. Credit: NASA/CXC/M. Weiss

Anomalous features

By the way, as part of a new study, a team led by J.J. Hermes, an astronomer from Boston University, revealed several more anomalous features of the runaway star under study. This was helped by data collected using the NASA Transiting Exoplanet Survey Satellite. This device was designed to search for distant transit planets, which pass in orbit and block the light of their stars with a certain periodicity as if darkening them.


Object LP 40-365 had a similar cycle – it dims and brightens every 8.9 hours. This surprised scientists because there are no rotating planets around this fragment of the star, that is, there are no objects that could block the glow.

Hypotheses and confirmations

The unusual object was studied using the Hubble Space Telescope after suspicions that the flickering may be due to hardware errors. However, this data only confirmed the data of TESS. Thus, the existence of the “clock mechanism” of the flickering of the mysterious object was confirmed by independent observations. Now scientists are considering several hypotheses that could explain this phenomenon.

Join the discussion and participate in awesome giveaways in our mobile Telegram group. Join Curiosmos on Telegram Today.



Dobrijevic, D. (2021, August 6). Scientists find chunk of Blown-apart star hurtling Through Milky way at breakneck speed.
Hermes, J. J., & Putterman, O. (n.d.). 8.9 hr Rotation in the Partly Burnt Runaway Stellar Remnant LP 40-365 (GD 492). The Astrophysical Journal Letters.
O’Neill, M. (2021, August 12). Bizarre, metallic star Spotted Hurtling out of the Milky way at 2 million miles an hour. SciTechDaily.
Schultz, I. (2021, August 5). This blasted star is getting the hell out of the milky way. Gizmodo.
Wood, C. (2021, August 11). Runaway star caught streaking across Milky way at 2 Million mph … in the wrong direction. LiveScience.

Written by Vladislav Tchakarov

Hello, my name is Vladislav and I am glad to have you here on Curiosmos. As a history student, I have a strong passion for history and science, and the opportunity to research and write in this field on a daily basis is a dream come true.

Write for us

We’re always looking for new guest authors and we welcome individual bloggers to contribute high-quality guest posts.

Get In Touch