Discovery Of A Meteor Of Interstellar Origin

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 99.999\% confidence. We infer that the meteor had an asymptotic speed of v∞∼42.1±5.5kms−1 outside of the solar system. Its origin is approximately towards R.A. 49.4±4.1∘ and declination 11.2±1.8∘, implying that its initial velocity vector was 58±6kms−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

Comments: 4 pages, 2 figures; submitted to ApJL; uncertainties updated
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1904.07224 [astro-ph.EP] (or arXiv:1904.07224v3 [astro-ph.EP] for this version)
Submission history
From: Amir Siraj [view email]
[v1] Mon, 15 Apr 2019 17:59:59 UTC (157 KB)
[v2] Sat, 20 Apr 2019 18:22:48 UTC (182 KB)
[v3] Tue, 4 Jun 2019 21:22:50 UTC (183 KB)
https://arxiv.org/abs/1904.07224
Astrochemistry, Astrobiology