J/ApJS/242/15 VRI photometry & taxonomy for ≳2000 MBAs (Erasmus+, 2019)
A taxonomic study of asteroid families from KMTNET-SAAO multiband photometry.
Erasmus N., McNeill A., Mommert M., Trilling D.E., Sickafoose A.A.,
Paterson K.
<Astrophys. J. Suppl. Ser., 242, 15-15 (2019)>
=2019ApJS..242...15E 2019ApJS..242...15E (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets; Photometry, VRI
Keywords: minor planets, asteroids: individual Main-Belt asteroids; surveys
techniques: photometric
Abstract:
We present here multiband photometry for over 2000 Main-Belt
asteroids. For each target, we report the probabilistic taxonomy using
the measured V-R and V-I colors in combination with a
machine-learning-generated decision surface in color-color space.
Through this method, we classify >85% of our targets as one the four
main Bus-DeMeo complexes: S-, C-, X-, or D-type. Roughly one-third of
our targets have a known associated dynamic family, with 69 families
represented in our data. Within uncertainties, our results show no
discernible difference in taxonomic distribution between family
members and non-family members. Nine of the sixty-nine families
represented in our observed sample had 20 or more members present, and
therefore, we investigate the taxonomy of these families in more
detail and find excellent agreement with the literature. Out of these
nine well-sampled families, our data show that the Themis, Koronis,
Hygiea, Massalia, and Eunomia families display a high degree of
taxonomic homogeneity and that the Vesta, Flora, Nysa-Polana, and Eos
families show a significant level of mixture in taxonomies. Using the
taxonomic purity and the degree of dispersion in observed colors for
each of the nine well-sampled collisional families, we also speculate
which of these families potentially originated from a differentiated
parent body and/or is a family with a possible undetermined nested
family. In addition, we obtained sufficient photometric data for 433
of our targets to extract reliable rotation periods and observe no
obvious correlation between rotation properties and family membership.
Description:
Observations were performed during two campaigns.
The first campaign took place between 2016 October and 2017 February
over four observing weeks and was originally intended for a near-Earth
asteroid (NEA) study (Erasmus+ 2017, J/AJ/154/162). However, the
large field of view meant that the fields observed in that study also
included ∼1000 serendipitously observed Main-Belt asteroids (MBAs)
(Erasmus+ 2018, J/ApJS/237/19).
The second campaign included one observing week in 2017 October and
another observing week in 2018 February. For the second campaign, no
specific asteroids were targeted but the observing strategy was to
observe close to the ecliptic to maximize the number of MBAs captured
in a single field. Approximately 1300 MBAs were observed during the
second campaign.
The telescope used for the two campaigns was the Sutherland, South
Africa node of the 1.6m Korea Microlensing Telescope Network (KMTNet).
Observations were performed alternating among the V (λ=550nm,
Δλ=90nm), R (λ=660nm, Δλ=140nm), and
I (λ=805nm, Δλ=150nm) filters in the sequence
VRVI, repeating the sequence continuously for the entire observing
duration. The exposure time for each filter was 60s for campaign one
and 120s for campaign two.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 157 2276 Main-Belt asteroid (MBA) observations and results
--------------------------------------------------------------------------------
See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
J/A+A/545/A131 : Photometry of 8 main belt asteroids (Marciniak+, 2012)
J/A+A/578/A42 : Main Belt asteroids observed by Spitzer (Ryan+, 2015)
J/A+A/596/A40 : Main-belt asteroids optical light curves (Szabo+, 2016)
J/AJ/154/162 : KMTNet-SAAO obs. of near-Earth asteroids (Erasmus+, 2017)
J/ApJS/234/37 : R-band K2 photometry of main-belt asteroids (Molnar+, 2018)
J/ApJS/237/19 : KMTNet LCs of ∼1000 main-belt asteroids (Erasmus+, 2018)
http://ssd.jpl.nasa.gov/horizons.cgi/ : HORIZONS Web-Interface
http://minorplanetcenter.net/ : IAU minor planet center home page
http://pds.nasa.gov/ : NASA Planetary Data System home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq Running sequence number
6- 11 I6 --- Planet ? Asteroid number
13- 27 A15 --- OName Other name of the object
29- 38 A10 --- Name Object identifier
40- 52 F13.5 d JD Julian Date of observation start
54- 57 A4 "h:m" Dur Observation duration
59- 62 F4.1 mag Hmag [8/19.5] H magnitude (1)
64- 68 F5.2 mag Vmag [13.2/21.6] V band magnitude
70- 74 F5.2 mag V-R [-1/0.4] The (V-R) color index (2)
76- 79 F4.2 mag e_V-R [0.01/0.3] Uncertainty in V-R
81- 85 F5.2 mag V-I [-0.5/0.6] The (V-I) color index (2)
87- 90 F4.2 mag e_V-I [0.01/0.4] Uncertainty in V-I
92- 95 A4 --- l_Amp [{=>} ] Limit flag on Amp (3)
97-101 F5.2 mag Amp [0.02/1.4] Amplitude
103-106 F4.2 mag e_Amp [0.02/0.2]? Uncertainty in Amp
108-111 A4 --- l_Per [{=>} ] Limit flag on Per (3)
113-115 I3 min Per [21/659] Rotational period
117-119 I3 min e_Per [9/233]? Uncertainty in Per
121-125 F5.3 --- S-type [0/1] S-type probability
127-131 F5.3 --- X-type [0/1] X-type probability
133-137 F5.3 --- C-type [0/1] C-type probability
139-143 F5.3 --- D-type [0/0.9] D-type probability
145 A1 --- Tax Taxonomy (4)
147-157 A11 --- Family Family (5)
--------------------------------------------------------------------------------
Note (1): H magnitude was obtained from http://ssd.jpl.nasa.gov/horizons.cgi/
Note (2): Colors have been corrected for solar colors by subtracting the
respective V-R=0.41 and V-I=0.75 solar colors
(Binney & Merrifield 1998gaas.book.....B 1998gaas.book.....B).
Note (3): Lower limit shown in cases where observational duration was
insufficient to observe entire light-curve period.
Note (4): Taxonomy:
S = 1166 occurrences;
C = 673 occurrences;
X = 141 occurrences;
D = 17 occurrences
- = 279 occurrences.
Note (5): We cross-correlate with NASA's Small Bodies Data Ferret database
(SBDF) Nesvorny (2015PDSS..234.....N 2015PDSS..234.....N) to associate objects
from our survey data with known collisional families.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Dec-2019