SPITZEREVIDENCE FOR A LATE-HEAVY BOMBARDMENT AND THE FORMATION OF UREILITES IN η CORVI At ∼1 Gyr
- 21 February 2012
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 747 (2), 93
- https://doi.org/10.1088/0004-637x/747/2/93
Abstract
We have analyzed Spitzer and NASA/IRTF 2-35 μm spectra of the warm, ~350 K circumstellar dust around the nearby MS star η Corvi (F2V, 1.4 ± 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at ~3 AU from the central star, in the system's terrestrial habitability zone. Spectral features due to ultra-primitive cometary material were found, in addition to features due to impact produced silica and high-temperature carbonaceous phases. At least 9 × 1018 kg of 0.1-100 μm warm dust is present in a collisional equilibrium distribution with dn/da ~ a –3.5, the equivalent of a 130 km radius Kuiper Belt object (KBO) of 1.0 g cm3 density and similar to recent estimates of the mass delivered to the Earth at 0.6-0.8 Gyr during the late-heavy bombardment. We conclude that the parent body was a Kuiper Belt body or bodies which captured a large amount of early primitive material in the first megayears of the system's lifetime and preserved it in deep freeze at ~150 AU. At ~1.4 Gyr they were prompted by dynamical stirring of their parent Kuiper Belt into spiraling into the inner system, eventually colliding at 5-10 km s–1 with a rocky planetary body of mass ≤M Earth at ~3 AU, delivering large amounts of water (>0.1% of M Earth 's Oceans) and carbon-rich material. The Spitzer spectrum also closely matches spectra reported for the Ureilite meteorites of the Sudan Almahata Sitta fall in 2008, suggesting that one of the Ureilite parent bodies was a KBO.This publication has 100 references indexed in Scilit:
- Dust ring formation due to ice sublimation of radially drifting dust particles under the Poynting–Robertson effect in debris disksIcarus, 2008
- Long‐Term Collisional Evolution of Debris DisksThe Astrophysical Journal, 2008
- Survival of icy grains in debris discsAstronomy & Astrophysics, 2007
- Dust Processing in Disks around T Tauri StarsThe Astrophysical Journal, 2006
- Extreme collisions between planetesimals as the origin of warm dust around a Sun-like starNature, 2005
- Detecting the Dusty Debris of Terrestrial Planet FormationThe Astrophysical Journal, 2004
- Contamination and melt aggregation processes in continental flood basalts: constraints from melt inclusions in Oligocene basalts from YemenEarth and Planetary Science Letters, 2002
- Detection of carbonates in dust shells around evolved starsNature, 2002
- How Observations of Circumstellar Disk Asymmetries Can Reveal Hidden Planets: Pericenter Glow and Its Application to the HR 4796 DiskThe Astrophysical Journal, 1999
- Impact and explosion crater ejecta, fragment size, and velocityIcarus, 1985