[Paper Review] Visual Spectroscopy of Asteroids at San Pedro Martir

A. Manara, S. Covino+1 more|arXiv (Cornell University)|Jan 11, 2001

Astro and Planetary Science1 references3 citations

TL;DR

This study presents low-resolution visual spectroscopy (5000–10000 Å) of four asteroids—three from the Nysa family and one near-Earth object—using the 2.1 m telescope at San Pedro Martir Observatory. The analysis reveals that (2007) McCuskey and (3130) Hillary are consistent with F-type, (3384) Daliya with S-type, and (3908) Nyx with V-type, suggesting it may be a fragment from the asteroid Vesta.

ABSTRACT

We present low resolution reflectance spectra over the wavelength range 5000-10000Åfor 4 asteroids (3 belonging to the Nysa family and one near-Earth asteroid) obtained at the San Pedro Martir Observatory (Mexico) using the 2.1 m telescope. Though the limited wavelength range covered often makes a classification difficult, the analysis of the available data reveals that two asteroids of the Nysa family, (2007) McCuskey and (3130) Hillary, are probably of F-type and (3384) Daliya of S-type. Near-Earth asteroid (3908) Nyx (Amor asteroid) shows a spectrum, within the limits of our signal-to-noise ratio (S/N), consistent with a V-type taxonomic classification and may be a fragment excavated from Vesta by an impact.

Motivation & Objective

• To investigate the mineralogical composition of asteroids in the Nysa family through low-resolution visual spectroscopy.
• To determine whether (3908) Nyx, a near-Earth Amor-type asteroid, matches the spectral signature of V-type asteroids associated with Vesta.
• To assess the taxonomic classification of selected asteroids using reflectance spectra within a limited wavelength range (5000–10000 Å).
• To contribute to the ongoing debate on the source of ordinary chondrite meteorites by identifying potential parent bodies.
• To evaluate the reliability of spectral data obtained under observational constraints, including signal-to-noise ratio and atmospheric effects.

Proposed method

• Spectra were obtained using the Boller & Chivens spectrograph on the 2.1 m telescope at San Pedro Martir Observatory, with a dispersion of 8 Å/pixel and a 150 gr/mm grating.
• Wavelength calibration was performed using a He–Ar lamp, and airmass corrections were applied using the San Pedro Martir mean extinction curve.
• Bias subtraction, flat-fielding, and background subtraction were applied using the ESO-MIDAS package to ensure accurate data reduction.
• Solar analogs (16 Cyg B and HD 191854) were observed to compute reflectance spectra, normalized at 7000 Å.
• Spectral reflectance curves were compared with known taxonomic types (F, S, V) from literature (e.g., Cellino et al. 2000; Xu et al. 1995; Binzel & Xu 1993).
• Signal-to-noise ratio and consistency checks across multiple observations confirmed data quality and reliability.

Experimental results

Research questions

• RQ1 Are the reflectance spectra of (2007) McCuskey and (3130) Hillary consistent with F-type asteroid classification?
• RQ2 Does (3384) Daliya’s spectrum align with S-type or indicate it may be an interloper in the Nysa family?
• RQ3 Is the near-Earth asteroid (3908) Nyx spectrally consistent with V-type classification, suggesting a possible origin from the asteroid Vesta?
• RQ4 Can low-resolution spectra in the 5000–10000 Å range reliably classify asteroid types despite limited wavelength coverage?
• RQ5 What does the spectral similarity between (3908) Nyx and V-type objects imply about its dynamical and compositional history?

Key findings

• The reflectance spectrum of (2007) McCuskey is consistent with an F-type classification, matching known F-type spectral features.
• The spectrum of (3130) Hillary also shows strong similarity to F-type asteroids, supporting its classification within the F-type subgroup of the Nysa family.
• (3384) Daliya exhibits a spectral curve typical of S-type asteroids, indicating a silicate-rich composition.
• The spectrum of (3908) Nyx displays a strong absorption feature near 9500 Å, characteristic of V-type asteroids, suggesting a possible origin from the asteroid Vesta.
• Despite limited wavelength coverage (4800–10000 Å), the data quality and consistency checks confirm reliable spectral classification within the signal-to-noise limits.
• The spectral similarity between (3908) Nyx and V-type members of the Vesta family supports the hypothesis that it may be a fragment ejected from Vesta by an impact.