Discovery of a Meteor of Interstellar Origin


Trajectory of the January 8, 2014 meteor (red), shown intersecting with that of Earth (blue) at the time of impact, ti = 2014-01-08 17:05:34.

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.

Amir Siraj, Abraham Loeb
(Submitted on 15 Apr 2019)

Comments: 4 pages, 2 figures; submitted to ApJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1904.07224 [astro-ph.EP] (or arXiv:1904.07224v1 [astro-ph.EP] for this version)
Submission history
From: Amir Siraj
[v1] Mon, 15 Apr 2019 17:59:59 UTC (157 KB)
https://arxiv.org/abs/1904.07224

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