Discovery of a Meteor of Interstellar OriginOPEN ACCESS 

Amir Siraj, Abraham Loeb

PDF (OPEN ACCESS)

submitted to The Astrophysical Journal Letters

“The first interstellar object, `Oumuamua, was discovered in the Solar System by Pan-STARRS in 2017, allowing for a calibration of the abundance of interstellar objects of its size ∼100 m. One would expect a much higher abundance of smaller interstellar objects, with some of them colliding with Earth frequently enough to be noticeable. Based on the CNEOS catalog of bolide events, we identify the ∼0.45m meteor detected at 2014-01-08 17:05:34 UTC as originating from an unbound hyperbolic orbit with an asymptotic speed of v∞∼43.8kms−1 outside of the solar system. Its origin is approximately towards R.A. 3h24m and declination +10.4∘, implying that its initial velocity vector was ∼60kms−1 away from the velocity of the Local Standard of Rest (LSR). Its high LSR speed implies a possible origin from the deep interior of a planetary system or a star in the thick disk of the Milky Way galaxy. The local number density of its population is 106+0.75−1.5AU−3 or 9×1021+0.75−1.5pc−3 (necessitating 0.2 – 20 Earth masses of material to be ejected per local star). This discovery enables a new method for studying the composition of interstellar objects, based on spectroscopy of their gaseous debris as they burn up in the Earth’s atmosphere. “