Near-infrared spectroscopic characterization of the Pallas family

Fuente: arXiv
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Auteurs principaux: Chavan, Prachi, Yang, Bin, Brož, Miroslav, Hanuš, Josef
Format: Preprint
Publié: 2025
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author Chavan, Prachi
Yang, Bin
Brož, Miroslav
Hanuš, Josef
author_facet Chavan, Prachi
Yang, Bin
Brož, Miroslav
Hanuš, Josef
contents The Pallas collisional family of asteroids, named after (2) Pallas, is notable for its high orbital inclination and the distinct blue color of Pallas and a few larger B-type family members. While Pallas itself, as one of the largest asteroids, has been studied in detail, most of its smaller family members still remain unexplored. This study aims to characterize the physical properties of medium- to small-sized Pallas family asteroids to investigate the origin of their unusual blueness. Additionally, we explore the relationship between the Pallas family and the near-Earth object (NEO) (3200) Phaethon. We conducted near-infrared (NIR) spectroscopy with the NASA Infrared Telescope Facility (IRTF) to collect reflectance spectra for 22 asteroids, including one from the IRTF Legacy Archive. Spectroscopic and dynamical analyses were carried out to identify outliers, while additional data from NEOWISE and Gaia were incorporated to examine potential correlations among their physical properties. Meteorite analogs were identified through chi-square matching using samples from the RELAB database. The observed Pallas family asteroids exhibit nearly identical spectral profiles, suggesting a homogeneous composition of ejected material. Small variations in spectral slopes are observed, which may result from different levels of alteration experienced by individual asteroids, with some influence from variations in grain size. Most of the observed spectra of the Pallas asteroids, from 0.8 to 2.2 micron, closely resemble those of the CY and CI meteorites. The blueness of asteroid surfaces is likely due to the presence of magnetite, troilite, or phyllosilicates, which are products of aqueous alteration. The striking spectral similarity between (3200) Phaethon and Pallas family members of comparable sizes suggests a potential common origin.
format Preprint
id arxiv_https___arxiv_org_abs_2503_04524
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Near-infrared spectroscopic characterization of the Pallas family
Chavan, Prachi
Yang, Bin
Brož, Miroslav
Hanuš, Josef
Earth and Planetary Astrophysics
The Pallas collisional family of asteroids, named after (2) Pallas, is notable for its high orbital inclination and the distinct blue color of Pallas and a few larger B-type family members. While Pallas itself, as one of the largest asteroids, has been studied in detail, most of its smaller family members still remain unexplored. This study aims to characterize the physical properties of medium- to small-sized Pallas family asteroids to investigate the origin of their unusual blueness. Additionally, we explore the relationship between the Pallas family and the near-Earth object (NEO) (3200) Phaethon. We conducted near-infrared (NIR) spectroscopy with the NASA Infrared Telescope Facility (IRTF) to collect reflectance spectra for 22 asteroids, including one from the IRTF Legacy Archive. Spectroscopic and dynamical analyses were carried out to identify outliers, while additional data from NEOWISE and Gaia were incorporated to examine potential correlations among their physical properties. Meteorite analogs were identified through chi-square matching using samples from the RELAB database. The observed Pallas family asteroids exhibit nearly identical spectral profiles, suggesting a homogeneous composition of ejected material. Small variations in spectral slopes are observed, which may result from different levels of alteration experienced by individual asteroids, with some influence from variations in grain size. Most of the observed spectra of the Pallas asteroids, from 0.8 to 2.2 micron, closely resemble those of the CY and CI meteorites. The blueness of asteroid surfaces is likely due to the presence of magnetite, troilite, or phyllosilicates, which are products of aqueous alteration. The striking spectral similarity between (3200) Phaethon and Pallas family members of comparable sizes suggests a potential common origin.
title Near-infrared spectroscopic characterization of the Pallas family
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2503.04524