A Meteor of Apparent Interstellar Origin in the CNEOS Fireball Catalog

Abstract

The earliest confirmed 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. This was followed by the discovery of Borisov, which allowed for a similar calibration of its size ∼0.4–1 km. One would expect a much higher abundance of significantly 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 ∼0.45 m meteor detected at 2014 January 8 17:05:34 UTC as originating from an unbound hyperbolic orbit. The U.S. Department of Defense has released an official letter stating that “the velocity estimate reported to NASA is sufficiently accurate to indicate an interstellar trajectory,” which we rely on here as confirmation of the object’s interstellar trajectory. Based on the data provided by CNEOS, we infer that the meteor had an asymptotic speed of v ∞ ∼ 42.1 ± 5.5 km s−1 outside of the solar system. Note that v ∞ here refers to the velocity of the meteor outside the solar system, not the velocity of the meteor outside the atmosphere. Its origin is approximately toward R.A. 49.°4 ± 4.°1 and decl. 11.°2 ± 1.°8, implying that its initial velocity vector was 58 ± 6 km s−1 away from the velocity of the local standard of rest (LSR).

Chasing nomadic worlds: A new class of deep space missions

“…The exponent for the number density (1) is somewhat steeper than the prediction in [105,11], who generated a power-law fit for interstellar meteoroids and meteors, but happens to be consistent with [99]. We comment on the accuracy of extrapolating (1) to objects approaching planetary sizes below, as they are of immediate relevance to this paper.…”

“…A power-law exponent of roughly −3 has been adopted in (1) by drawing on available data regarding ISOs and interstellar dust grains [8,9,11,88,97,98,99,100,101], as well as free-floating planets (addressed a couple of paragraphs later). The numerical values in this equation are based on constraints stemming from the discovery of 1I/'Oumuamua [102,103,104,80,98,94,14,101].…”

“…The field of ISOs was already quite active by the 1970s [2,3,4], but it has received a timely boost thanks to the recent discovery of the interstellar planetesimals 1I/'Oumuamua and 2I/Borisov in 2017 [5] and 2019 [6,7], respectively. Aside from this duo, interstellar dust grains and meteors have been analyzed, and their abundances constrained [8,9,10,11,12]; note, however, that their sizes are many orders of magnitude smaller than the class of objects tackled hereafter. These two interstellar interlopers have substantially enhanced our knowledge of ISOs [13,14,15,16], such as the size distribution and number density of interstellar planetesimals, while raising new questions in their wake.…”

On the Proposed Interstellar Origin of the USG 20140108 Fireball

“…The recent telescopic detection of two interstellar objects in the inner solar system, namely 1I/'Oumuamua and 2I/Borisov (Jewitt & Seligman 2022), have reinvigorated the search for interstellar meteoroids in the Earth's neighborhood. Siraj & Loeb (2022) have recently claimed the detection of a metersized interstellar meteoroid detected on 2014 January 8 based on data from US Government sensors. This is a surprising result given that numerous surveys at smaller meteoroid sizes have searched for and as yet not found convincing evidence for true interstellar meteoroids from ground-based detectors (Hajduková et al 2019;Froncisz et al 2020;Musci et al 2012).…”

Interstellar Meteors Are Outliers in Material Strength

“…In this Letter, we describe an interstellar meteor candidate from the CNEOS catalog mentioned in Table 8 of Peña-Asensio et al (2022) and in Section 5 of Siraj & Loeb (2022b), which we refer to as IM2. We then explore the statistical likelihood that interstellar meteors reflect the same distribution of material strength as noninterstellar meteors.…”