TOWARDS A MULTI-DIMENSIONAL CLASSIFICATION SCHEME FOR MINOR PLANETS
Max Mahlke Centro de Astrobiología (CSIC-INTA)
in collaboration with Enrique Solano, Benoit Carry, Bruno Merín, Remi Flamary, the Spanish Virtual Observatory and the ESASky team TOWARDS A MULTI-DIMENSIONAL CLASSIFICATION SCHEME FOR MINOR PLANETS
Max Mahlke Centro de Astrobiología (CSIC-INTA)
in collaboration with Enrique Solano, Benoit Carry, Bruno Merín, Remi Flamary, the Spanish Virtual Observatory and the ESASky team
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA 1 Ceres DeMeo+ 2015
Max Mahlke | ESAC Science Seminar | 13 June 2019 2 Pallas Pallas Mercury Venus Earth Mars Ceres Juno Jupiter Saturn Uranus Vesta
DeMeo+ 2015
Max Mahlke | ESAC Science Seminar | 13 June 2019 2 Pallas Pallas Mercury Venus Earth Mars Ceres Juno Jupiter Saturn UranusNeptune Vesta
DeMeo+ 2015
Max Mahlke | ESAC Science Seminar | 13 June 2019 2 Pallas Mercury Venus Earth Mars Jupiter Saturn UranusNeptune
DeMeo+ 2015
Max Mahlke | ESAC Science Seminar | 13 June 2019 2 Pallas Mercury Venus Earth Mars Jupiter Saturn UranusNeptune Pluto
DeMeo+ 2015
Max Mahlke | ESAC Science Seminar | 13 June 2019 2 Pallas 1992 QB Mercury Venus Earth Mars Jupiter Saturn UranusNeptune Pluto Albion
DeMeo+ 2015
Max Mahlke | ESAC Science Seminar | 13 June 2019 2 Pallas Mercury Venus Earth Mars Jupiter Saturn UranusNeptune
DeMeo+ 2015
Max Mahlke | ESAC Science Seminar | 13 June 2019 2 Pallas Mercury Venus Earth Mars Jupiter Saturn UranusNeptune
June 2019: 795,000
DeMeo+ 2015
Max Mahlke | ESAC Science Seminar | 13 June 2019 2 Pallas Centaurs Trans-Neptunian Objects
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DeMeo & Carry 2014
Heterogeneous
in heliocentric distance: <1AU to >100AU in shapes in orbital inclination: 0° to 33° for Main Belt asteroids in rotation: hours to days in orbital eccentricity: 0. to 0.3 for Main Belt asteroids
in size: m to 103km in composition: carbon- / silicate-compound rocks, ices
Max Mahlke | ESAC Science Seminar | 13 June 2019 3 Juno Centaurs Trans-Neptunian Objects
//
DeMeo & Carry 2014
Heterogeneous
in heliocentric distance: <1AU to >100AU in shapes in orbital inclination: 0° to 33° for Main Belt asteroids in rotation: hours to days in orbital eccentricity: 0. to 0.3 for Main Belt asteroids
in size: m to 103km in composition: carbon- / silicate-compound rocks, ices
in common: they are all witnesses of the formation of the Solar System
Max Mahlke | ESAC Science Seminar | 13 June 2019 3 Juno Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Asteroid puzzle
-4 Little mass in Main Belt (5x10 MEarth) Dynamically excited Main Belt Compositionally diverse Main Belt Compositionally homogeneous Trojans
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta DeMeo & Carry 2014 Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Asteroid puzzle
-4 Little mass in Main Belt (5x10 MEarth) Dynamically excited Main Belt Compositionally diverse Main Belt Compositionally homogeneous Trojans
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Asteroid puzzle
-4 Little mass in Main Belt (5x10 MEarth) Dynamically excited Main Belt Compositionally diverse Main Belt Compositionally homogeneous Trojans
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Planet migration
Asteroid puzzle
-4 Little mass in Main Belt (5x10 MEarth) Dynamically excited Main Belt Compositionally diverse Main Belt Compositionally homogeneous Trojans
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Planet migration
Asteroid puzzle
-4 Little mass in Main Belt (5x10 MEarth) Dynamically excited Main Belt Compositionally diverse Main Belt Compositionally homogeneous Trojans
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Planet migration
Orbital instabilities
Asteroid puzzle
-4 Little mass in Main Belt (5x10 MEarth) Dynamically excited Main Belt Compositionally diverse Main Belt Compositionally homogeneous Trojans
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Planet migration
Orbital instabilities
Asteroid puzzle
-4 Little mass in Main Belt (5x10 MEarth) Dynamically excited Main Belt Compositionally diverse Main Belt Compositionally homogeneous Trojans
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta Dust Gas
DeMeo & Carry 2014 Pebbles Planetesimals Planetary Embryos Gas Giants
Terrestrial Planets
Planet migration
Orbital instabilities
Asteroid puzzle
-4 Little mass in Main Belt (5x10 MEarth) Dynamically excited Main Belt Compositionally diverse Main Belt Compositionally homogeneous Trojans
Max Mahlke | ESAC Science Seminar | 13 June 2019 4 Vesta Previous Taxonomies: What features did they use, how many classes, how large were their samples
Chapman+ 1975
S C U "stony", "silicaceous" "carbonaceous" "unclassified"
Max Mahlke | ESAC Science Seminar | 13 June 2019 5 Astraea Previous Taxonomies: What features did they use, how many classes, how large were their samples
Chapman+ 1975
S C U "stony", "silicaceous" "carbonaceous" "unclassified"
V P X
A B M
R D E
+ composite classes K L + hydrated cases
DeMeo+ 2009
Max Mahlke | ESAC Science Seminar | 13 June 2019 5 Astraea Previous Taxonomies: What features did they use, how many classes, how large were their samples
Chapman+ 1975
S C U "stony", "silicaceous" "carbonaceous" "unclassified"
V P X
A B M
R D E
+ composite classes K L + hydrated cases
Classes are defined by features in the asteroid spectra
VIS / NIR slope Absorption bands, most importantly at 1mu (olivine) 2mu (pyroxene) DeMeo+ 2009
Some caveats
Classes are degenerate when regarding only VIS or only NIR In general, low number of asteroid spectra to define classes
Max Mahlke | ESAC Science Seminar | 13 June 2019 5 Astraea Previous Taxonomies: What features did they use, how many classes, how large were their samples
Chapman+ 1975
S C U "stony", "silicaceous" "carbonaceous" "unclassified"
V P X
A B M
R D E
+ composite classes K L + hydrated cases
Classes are defined by features in the asteroid spectra
VIS / NIR slope Absorption bands, most importantly at 1mu (olivine) 2mu (pyroxene) DeMeo+ 2009
Some caveats
Classes are degenerate when regarding only VIS or only NIR In general, low number of asteroid spectra to define classes
Max Mahlke | ESAC Science Seminar | 13 June 2019 5 Astraea Previous Taxonomies: What features did they use, how many classes, how large were their samples
Chapman+ 1975
S C U "stony", "silicaceous" "carbonaceous" "unclassified"
V P X
A B M
DeMeo+ 2009 R D E
+ composite classes K L + hydrated cases
Classes are defined by features in the asteroid spectra
VIS / NIR slope Absorption bands, most importantly at 1mu (olivine) 2mu (pyroxene) DeMeo+ 2009
Some caveats
Classes are degenerate when regarding only VIS or only NIR In general, low number of asteroid spectra to define classes
Max Mahlke | ESAC Science Seminar | 13 June 2019 5 Astraea Tholen 1984 Asteroids can also be classified by their albedos
albedo is the "capability to reflect light" visual albedo, infrared albedo, and their ratios the albedo carries less information, but is more readily available than the spectra
Max Mahlke | ESAC Science Seminar | 13 June 2019 6 Hebe Tholen 1984 Asteroids can also be classified by their albedos
albedo is the "capability to reflect light" visual albedo, infrared albedo, and their ratios the albedo carries less information, but is more readily available than the spectra
Mainzer+ 2012
Max Mahlke | ESAC Science Seminar | 13 June 2019 6 Hebe Tholen 1984 Asteroids can also be classified by their albedos
albedo is the "capability to reflect light" visual albedo, infrared albedo, and their ratios the albedo carries less information, but is more readily available than the spectra
Masiero+ 2011 Mainzer+ 2012
Max Mahlke | ESAC Science Seminar | 13 June 2019 6 Hebe Asteroids can also be classified by their phase curves
slope parameters G1 and G2 defining the decrease in brightness as the solar phase angle increases
less information than than albedos and spectra, but available from serendipitous observations
Buchheim 2010
Muinonen 2010+
Max Mahlke | ESAC Science Seminar | 13 June 2019 7 Iris Asteroids can also be classified by their phase curves
slope parameters G1 and G2 defining the decrease in brightness as the solar phase angle increases
less information than than albedos and spectra, but available from serendipitous observations
Buchheim 2010
Penttilä+ 2016
Muinonen 2010+
Max Mahlke | ESAC Science Seminar | 13 June 2019 7 Iris Courtesy of B. Carry
VISNIR: Available for 800 objects Available for 200,000 objects Available for 500,000 objects VIS/NIR: Available for 4,000 objects
Our data collection so far includes 7,500 spectra of 3,500 unique objects, including 1,000 VISNIR spectra, provided to us by >30 PIs
Compared to the DeMeo classification from 2009
Larger sample size (factor 2 for VISNIR, factor 10 for VIS/NIR) Multi-dimensional: spectra, albedo, phase curve Give probabilistic classifications
Max Mahlke | ESAC Science Seminar | 13 June 2019 8 Flora Courtesy of B. Carry
VISNIR: Available for 800 objects Available for 200,000 objects Available for 500,000 objects VIS/NIR: Available for 4,000 objects
VIS NIR Albedo Phase Curve
Our data collection so far includes 7,500 spectra of 3,500 unique objects, including 1,000 VISNIR spectra, provided to us by >30 PIs
Compared to the DeMeo classification from 2009
Larger sample size (factor 2 for VISNIR, factor 10 for VIS/NIR) Multi-dimensional: spectra, albedo, phase curve Give probabilistic classifications
Max Mahlke | ESAC Science Seminar | 13 June 2019 8 Flora Courtesy of B. Carry
VISNIR: Available for 800 objects Available for 200,000 objects Available for 500,000 objects VIS/NIR: Available for 4,000 objects
VIS NIR Albedo Phase Curve
Our data collection so far includes 7,500 spectra of 3,500 unique objects, including 1,000 VISNIR spectra, provided to us by >30 PIs
Compared to the DeMeo classification from 2009
Larger sample size (factor 2 for VISNIR, factor 10 for VIS/NIR) Multi-dimensional: spectra, albedo, phase curve Give probabilistic classifications
Max Mahlke | ESAC Science Seminar | 13 June 2019 8 Flora Courtesy of B. Carry
VISNIR: Available for 800 objects Available for 200,000 objects Available for 500,000 objects VIS/NIR: Available for 4,000 objects
VIS NIR Albedo Phase Curve
Our data collection so far includes 7,500 spectra of 3,500 unique objects, including 1,000 VISNIR spectra, provided to us by >30 PIs
Compared to the DeMeo classification from 2009
Larger sample size (factor 2 for VISNIR, factor 10 for VIS/NIR) Multi-dimensional: spectra, albedo, phase curve Give probabilistic classifications
Max Mahlke | ESAC Science Seminar | 13 June 2019 8 Flora VISNIR spectra of 713 unique objects
Max Mahlke | ESAC Science Seminar | 13 June 2019 9 Metis Max Mahlke | ESAC Science Seminar | 13 June 2019 10 Hygiea Max Mahlke | ESAC Science Seminar | 13 June 2019 11 Parthenope Max Mahlke | ESAC Science Seminar | 13 June 2019 12 Victoria Conclusions
Asteroids are the remnants of the building blocks They are heterogeneous in many ways and we are still of the Solar System trying to work out the best way to group them
Their current orbital and chemical distributions Their spectral features are most useful in characterizing constrain models on the evolution of the Solar them, while the albedo and phase curve parameters are System more readily available
Outlook Upcoming gamechangers
2013 Gaia High-resolution astrometry + photometry for 350,000 asteroids
2022 Euclid NIR colors for 150,000 high-inclination asteroids 2023 LSST Orbits + visible colors for several millions of asteroids
Max Mahlke | ESAC Science Seminar | 13 June 2019 13 Egeria Conclusions
Asteroids are the remnants of the building blocks They are heterogeneous in many ways and we are still of the Solar System trying to work out the best way to group them
Their current orbital and chemical distributions Their spectral features are most useful in characterizing constrain models on the evolution of the Solar them, while the albedo and phase curve parameters are System more readily available
Outlook Upcoming gamechangers
2013 Gaia High-resolution astrometry + photometry for 350,000 asteroids
2022 Euclid NIR colors for 150,000 high-inclination asteroids 2023 LSST Orbits + visible colors for several millions of asteroids
Personal Outlook PhD supported by ESA NPI
Benoit Carry Bruno Altieri Nicolas Altobelli Michael Küppers
Max Mahlke | ESAC Science Seminar | 13 June 2019 13 Egeria