Abstract
We review previously published and newly obtained crater size-frequency distributions in the inner solar system. These data indicate that the Moon and the terrestrial planets have been bombarded by two populations of objects. Population 1, dominating at early times, had nearly the same size distribution as the present-day asteroid belt, and produced heavily cratered surfaces with a complex, multi-sloped crater size-frequency distribution. Population 2, dominating since about 3.8-3.7 Gyr, had the same size distribution as near-Earth objects (NEOs) and a much lower impact flux, and produced a crater size distribution characterized by a differential -3 single-slope power law in the crater diameter range 0.02 km to 100 km. Taken together with the results from a large body of work on age-dating of lunar and meteorite samples and theoretical work in solar system dynamics, a plausible interpretation of these data is as follows. The NEO population is the source of Population 2 and it has been in near-steady state over the past ∼ 3.7-3.8 Gyr; these objects are derived from the main asteroid belt by size-dependent non-gravitational effects that favor the ejection of smaller asteroids. However, Population 1 was composed of main belt asteroids ejected from their source region in a size-independent manner, possibly by means of gravitational resonance sweeping during orbit migration of giant planets; this caused the so-called Late Heavy Bombardment (LHB). The LHB began some time before ∼3.9 Gyr, peaked and declined rapidly over the next ∼ 100 to 300 Myr, and possibly more slowly from about 3.8-3.7 Gyr to ∼2 Gyr. A third crater population (Population S) consisted of secondary impact craters that can dominate the cratering record at small diameters.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 407-434 |
| Number of pages | 28 |
| Journal | Research in Astronomy and Astrophysics |
| Volume | 15 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 1 2015 |
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Keywords
- Earth
- Minor planets, asteroids
- Moon
- Solar system: formation
ASJC Scopus subject areas
- Space and Planetary Science
- Astronomy and Astrophysics
Cite this
The inner solar system cratering record and the evolution of impactor populations. / Strom, Robert G.; Malhotra, Renu; Xiao, Zhi Yong; Ito, Takashi; Yoshida, Fumi; Ostrach, Lillian R.
In: Research in Astronomy and Astrophysics, Vol. 15, No. 3, 01.03.2015, p. 407-434.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The inner solar system cratering record and the evolution of impactor populations
AU - Strom, Robert G.
AU - Malhotra, Renu
AU - Xiao, Zhi Yong
AU - Ito, Takashi
AU - Yoshida, Fumi
AU - Ostrach, Lillian R.
PY - 2015/3/1
Y1 - 2015/3/1
N2 - We review previously published and newly obtained crater size-frequency distributions in the inner solar system. These data indicate that the Moon and the terrestrial planets have been bombarded by two populations of objects. Population 1, dominating at early times, had nearly the same size distribution as the present-day asteroid belt, and produced heavily cratered surfaces with a complex, multi-sloped crater size-frequency distribution. Population 2, dominating since about 3.8-3.7 Gyr, had the same size distribution as near-Earth objects (NEOs) and a much lower impact flux, and produced a crater size distribution characterized by a differential -3 single-slope power law in the crater diameter range 0.02 km to 100 km. Taken together with the results from a large body of work on age-dating of lunar and meteorite samples and theoretical work in solar system dynamics, a plausible interpretation of these data is as follows. The NEO population is the source of Population 2 and it has been in near-steady state over the past ∼ 3.7-3.8 Gyr; these objects are derived from the main asteroid belt by size-dependent non-gravitational effects that favor the ejection of smaller asteroids. However, Population 1 was composed of main belt asteroids ejected from their source region in a size-independent manner, possibly by means of gravitational resonance sweeping during orbit migration of giant planets; this caused the so-called Late Heavy Bombardment (LHB). The LHB began some time before ∼3.9 Gyr, peaked and declined rapidly over the next ∼ 100 to 300 Myr, and possibly more slowly from about 3.8-3.7 Gyr to ∼2 Gyr. A third crater population (Population S) consisted of secondary impact craters that can dominate the cratering record at small diameters.
AB - We review previously published and newly obtained crater size-frequency distributions in the inner solar system. These data indicate that the Moon and the terrestrial planets have been bombarded by two populations of objects. Population 1, dominating at early times, had nearly the same size distribution as the present-day asteroid belt, and produced heavily cratered surfaces with a complex, multi-sloped crater size-frequency distribution. Population 2, dominating since about 3.8-3.7 Gyr, had the same size distribution as near-Earth objects (NEOs) and a much lower impact flux, and produced a crater size distribution characterized by a differential -3 single-slope power law in the crater diameter range 0.02 km to 100 km. Taken together with the results from a large body of work on age-dating of lunar and meteorite samples and theoretical work in solar system dynamics, a plausible interpretation of these data is as follows. The NEO population is the source of Population 2 and it has been in near-steady state over the past ∼ 3.7-3.8 Gyr; these objects are derived from the main asteroid belt by size-dependent non-gravitational effects that favor the ejection of smaller asteroids. However, Population 1 was composed of main belt asteroids ejected from their source region in a size-independent manner, possibly by means of gravitational resonance sweeping during orbit migration of giant planets; this caused the so-called Late Heavy Bombardment (LHB). The LHB began some time before ∼3.9 Gyr, peaked and declined rapidly over the next ∼ 100 to 300 Myr, and possibly more slowly from about 3.8-3.7 Gyr to ∼2 Gyr. A third crater population (Population S) consisted of secondary impact craters that can dominate the cratering record at small diameters.
KW - Earth
KW - Minor planets, asteroids
KW - Moon
KW - Solar system: formation
UR - http://www.scopus.com/inward/record.url?scp=84924977695&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84924977695&partnerID=8YFLogxK
U2 - 10.1088/1674-4527/15/3/009
DO - 10.1088/1674-4527/15/3/009
M3 - Article
VL - 15
SP - 407
EP - 434
JO - Research in Astronomy and Astrophysics
JF - Research in Astronomy and Astrophysics
SN - 1674-4527
IS - 3
ER -