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Title: NEOMOD 2: An updated model of Near-Earth Objects from a decade of Catalina Sky Survey observations
Catalina Sky Survey (CSS) is a major survey of Near-Earth Objects (NEOs). In a recent work, we used CSS observations from 2005–2012 to develop a new population model of NEOs (NEOMOD). CSS’s G96 telescope was upgraded in 2016 and detected over 10,000 unique NEOs since then. Here we characterize the NEO detection efficiency of G96 and use G96’s NEO detections from 2013–2022 to update NEOMOD. This resolves previous model inconsistencies related to the population of large NEOs. We estimate there are 936 ± 29 NEOs with absolute magnitude 𝐻 < 17.75 (diameter 𝐷 > 1 km for the reference albedo 𝑝V = 0.14) and semimajor axis 𝑎 < 4.2 au. The slope of the NEO size distribution for 𝐻 = 25–28 is found to be relatively shallow (cumulative index ≃ 2.6) and the number of 𝐻 < 28 NEOs (𝐷 > 9 m for 𝑝V = 0.14) is determined to be (1.20 ± 0.04) × 107 , about 3 times lower than in Harris & Chodas (2021). Small NEOs have a different orbital distribution and higher impact probabilities than large NEOs. We estimate 0.034 ± 0.002 impacts of 𝐻 < 28 NEOs on the Earth per year, which is near the low end of the impact flux range inferred from atmospheric bolide observations. Relative to a model where all NEOs are delivered directly from the main belt, the population of small NEOs detected by G96 shows an excess of low-eccentricity orbits with 𝑎 ≃ 1–1.6 au that appears to increase with 𝐻 (≃ 30% excess for 𝐻 = 28). We suggest that the population of very small NEOs is boosted by tidal disruption of large NEOs during close encounters to the terrestrial planets. When the effect of tidal disruption is (approximately) accounted for in the model, we estimate 0.06 ± 0.01 impacts of 𝐻 < 28 NEOs on the Earth per year, which is more in line with the bolide data. The impact probability of a 𝐻 < 22 (𝐷 > 140 m for 𝑝V = 0.14) object on the Earth in this millennium is estimated to be ≃ 4.5%  more » « less
Award ID(s):
2009775
PAR ID:
10554132
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ;
Editor(s):
NA
Publisher / Repository:
Elsevier
Date Published:
Journal Name:
Icarus
Volume:
411
Issue:
C
ISSN:
0019-1035
Page Range / eLocation ID:
115922
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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