Year: 2022
Type: article
Abstract: Context. The classification of the minor bodies of the Solar System based on observables has been continuously developed and iterated over the past 40 yr. While prior iterations followed either the availability of large observational campaigns or new instrumental capabilities opening new observational dimensions, we see the opportunity to improve primarily upon the established methodology. Aims. We developed an iteration of the asteroid taxonomy which allows the classification of partial and complete observations (i.e. visible, near-infrared, and visible-near-infrared spectrometry) and which reintroduces the visual albedo into the classification observables. The resulting class assignments are given probabilistically, enabling the uncertainty of a classification to be quantified. Methods. We built the taxonomy based on 2983 observations of 2125 individual asteroids, representing an almost tenfold increase of sample size compared with the previous taxonomy. The asteroid classes are identified in a lower-dimensional representation of the observations using a mixture of common factor analysers model. Results. We identify 17 classes split into the three complexes C, M, and S, including the new Z-class for extremely-red objects in the main belt. The visual albedo information resolves the spectral degeneracy of the X-complex and establishes the P-class as part of the C-complex. We present a classification tool which computes probabilistic class assignments within this taxonomic scheme from asteroid observations, intrinsically accounting for degeneracies between classes based on the observed wavelength region. The taxonomic classifications of 6038 observations of 4526 individual asteroids are published. Conclusions. The ability to classify partial observations and the reintroduction of the visual albedo into the classification provide a taxonomy which is well suited for the current and future datasets of asteroid observations, in particular provided by the Gaia, MITHNEOS, NEO Surveyor, and SPHEREx surveys.
Source: Astronomy and Astrophysics
Authors: M. Mahlke, B. Carry, P.-A. Mattei
Institutions: Centre National de la Recherche Scientifique, Université Côte d'Azur, Lagrange Laboratory, Observatoire de la Côte d’Azur, Institut national de recherche en sciences et technologies du numérique, Laboratoire Jean-Alexandre Dieudonné, MAASAI: Modèles et algorithmes pour l'intelligence artificielle
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,580
Awards: BACKGROUND: THE MIT-HAWAII NEAR EARTH OBJECT SURVEY (MITHNEOS) HAS BEEN SYSTEMATICALLY MEASURING NEO NEAR-INFRARED SPECTRA USING SPEX ON THE 3-METER NASA IRTF SINCE 2000. SINCE INCEPTION THIS PROGRAM HAS MEASURED NEAR-INFRARED SPECTRA OF OVER 700 NEAR-EARTH OBJECTS. WE HAVE OBSERVED ~3% OF THE KNOWN DELTA-V<7 KM/S POPULATION REPRESENTING ABOUT 270 NEOS 80 OF WHICH HAVE DELTA-V<6 KM/S. THE SURVEY HAS ALSO OBTAINED SPECTRA FOR ~15% OF THE KNOWN PHA POPULATION OR ABOUT 270 OBJECTS. ALL SPECTRAL OBSERVATIONS FROM THIS CAMPAIGN ARE MADE PUBLICLY AVAILABLE FOR THE COMMUNITY SHORTLY AFTER OBSERVATION AT HTTP://SMASS.MIT.EDU. OBSERVATIONS AND ANALYSIS FROM THIS PROGRAM HAVE HAD A LARGE IMPACT ON NEO SCIENCE SUCH AS: 1) ENHANCED UNDERSTANDING OF SPACE WEATHERING AND REFRESHING MECHANISMS (VERNAZZA ET AL. 2009 NATURE. BINZEL ET AL. 2010 NATURE DEMEO ET AL. 2014) 2) METEORITE-NEO LINKS AND NEO-MAIN BELT SOURCE REGION LINKS (VERNAZZA ET AL 2008 NATURE. THOMAS C.A.&BINZEL R. P. 2010) 3) CHARACTERIZATION OF EXTREMELY SMALL AND RAPIDLY ROTATING NEOS (POLISHOOK ET AL. 2012) 4) DEVELOPMENT OF TECHNIQUES TO DETERMINE ALBEDO AND SPIN ORIENTATION FROM THERMAL EMISSION PAST 2 MICRONS (RIVKIN ET AL. 2005 MOSKOVITZ ET AL. 2017) AND 5) THE VIS+NEAR-INFRARED SPECTRAL TAXONOMY USED BY THE COMMUNITY TO CLASSIFY ASTEROIDS (DEMEO ET AL. 2009). GOALS AND OBJECTIVES: THE PROGRAMMATIC OBJECTIVE OF THIS WORK IS TO SPECTRALLY CHARACTERIZE LOW DELTA-V NEOS AND PHAS. WE WILL MEASUREM 500 NEOS OVER A 5 YEAR PERIOD INCLUDING 150 LOW DELTA-V AND 150 PHA TARGETS. SCIENCE OBJECTIVES OF THIS PROGRAM ARE: 1) COMPOSITIONAL CHARACTERIZATION THROUGH TAXONOMIC CLASSIFICATION AND MINERALOGIC ANALYSIS 2) ALBEDO ESTIMATES FROM MODELING OF THERMAL EMISSION PAST TWO MICRONS. 3) IDENTIFICATION OF METEORITE ANALOGS 4) CHARACTERIZATION OF THE NEO POPULATION AND SUB-POPULATIONS INCLUDING MISSION ACCESSIBLE (LOW DELTA-VELOCITY TARGETS) POTENTIALLY HAZARDOUS ASTEROIDS (PHAS) AND DORMANT COMETS. 5) ANALYSIS OF THE CHANGE IN COMPOSITION OF THE NEO POPULATION AS A FUNCTION OF SIZE. 6) EXPLORATION OF C-COMPLEX DATA TO IDENTIFY DIAGNOSTIC SPECTRAL CHARACTERISTICS AT NEAR-INFRARED WAVELENGTHS. APPROACH AND METHODOLOGY: TARGET SELECTION WILL BE BASED ON NEOS OBSERVABLE ON REQUESTED NASA IRTF OBSERVING DATES BY SEARCHING AMONG LOW DELTA-V TARGETS AND PHAS. DATA WILL BE REDUCED USING THE AUTOSPEX PIPELINE THAT HAS BEEN CONSISTENTLY USED FOR THIS PROGRAM FOR WELL OVER A DECADE. SPECTRAL CLASSIFICATION WILL BE PERFORMED USING THE BUS-DEMEO CLASSIFICATION SYSTEM. SCIENTIFIC ANALYSIS WILL USE ESTABLISHED TECHNIQUES AND TOOLS WHERE APPROPRIATE SUCH AS PRINCIPAL COMPONENT ANALYSIS THERMAL MODELING OF SPECTRAL EMISSION TAILS MINERALOGICAL MODELING AND SPACE WEATHERING MODELING AND COMPARISON WITH THE RELAB METEORITE DATABASE. RELEVANCE AND APPROPRIATENESS TO SOLAR SYSTEM OBSERVATIONS NEOO: THE PROPOSED WORK IS RELEVANT AND APPROPRIATE TO THE SOLAR SYSTEM OBSERVATIONS NEOO PROGRAM BECAUSE AS THE PROGRAM SPECIFIES WE WILL PERFORM NEW GROUND-BASED OBSERVATIONS OF NEAR EARTH OBJECTS TO CHARACTERIZE THEIR COMPOSITIONS. THIS PROGRAM ALSO SUPPORTS THE NASA HUMAN EXPLORATION AND OPERATIONS MISSION DIRECTORATE IN THAT IT PRIORITIZES OBSERVATIONS OF LOW DELTA VELOCITY ORBITS RELATIVE TO EARTH. BECAUSE THE PROPOSED WORK FOCUSES SOLELY ON THE NEAR EARTH OBJECT POPULATION THE NEOO PROGRAM ELEMENT IS THE MOST APPROPRIATE. THE OBSERVATIONS AND OBJECTIVES OF THIS PROGRAM CANNOT BE ACHIEVED BY CURRENT SPACECRAFT MISSIONS., G2473458285
OpenAlex ID: W4283764484