Origin of Asteroid (101955) Bennu and its Connection to the New Polana Family

Fuente: arXiv
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Main Authors: Takir, Driss, Emery, Joshua P., Bottke, William F., Arredondo, Anicia
Format: Preprint
Published: 2024
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author Takir, Driss
Emery, Joshua P.
Bottke, William F.
Arredondo, Anicia
author_facet Takir, Driss
Emery, Joshua P.
Bottke, William F.
Arredondo, Anicia
contents The asteroid (142) Polana is classified as a B-type asteroid located in the inner Main Belt. This asteroid is the parent of the New Polana family, which has been proposed to be the likely source of primitive near-Earth asteroids such as the B-type asteroid (101955) Bennu. To investigate the compositional correlation between Polana and Bennu at the 3-micron band and their aqueous alteration histories, we analyzed the spectra of Polana in the ~2.0-4.0-micron spectral range using the NASA Infrared Telescope Facility in Hawaii. Our findings indicate that Polana does not exhibit discernable 3-micron hydrated mineral absorption (within 2 sigma), which is in contrast to asteroid Bennu. Bennu displayed a significant 3-micron absorption feature similar to CM- and CI-type carbonaceous chondrites. This suggests two possibilities: either Bennu did not originate from the New Polana family parented by asteroid Polana or the interior of Bennu's parent body was not homogenous, with diverse levels of aqueous alteration. Several explanations support the latter possibility, including heating due to shock waves and pressure, which could have caused the current dehydrated state of Bennu's parent body.
format Preprint
id arxiv_https___arxiv_org_abs_2406_19902
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Origin of Asteroid (101955) Bennu and its Connection to the New Polana Family
Takir, Driss
Emery, Joshua P.
Bottke, William F.
Arredondo, Anicia
Earth and Planetary Astrophysics
The asteroid (142) Polana is classified as a B-type asteroid located in the inner Main Belt. This asteroid is the parent of the New Polana family, which has been proposed to be the likely source of primitive near-Earth asteroids such as the B-type asteroid (101955) Bennu. To investigate the compositional correlation between Polana and Bennu at the 3-micron band and their aqueous alteration histories, we analyzed the spectra of Polana in the ~2.0-4.0-micron spectral range using the NASA Infrared Telescope Facility in Hawaii. Our findings indicate that Polana does not exhibit discernable 3-micron hydrated mineral absorption (within 2 sigma), which is in contrast to asteroid Bennu. Bennu displayed a significant 3-micron absorption feature similar to CM- and CI-type carbonaceous chondrites. This suggests two possibilities: either Bennu did not originate from the New Polana family parented by asteroid Polana or the interior of Bennu's parent body was not homogenous, with diverse levels of aqueous alteration. Several explanations support the latter possibility, including heating due to shock waves and pressure, which could have caused the current dehydrated state of Bennu's parent body.
title Origin of Asteroid (101955) Bennu and its Connection to the New Polana Family
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2406.19902