J/A+A/643/A59 Asteroid models reconstructed from ATLAS phot. (Durech+, 2020)
Asteroid models reconstructed from ATLAS photometry.
Durech J., Tonry J., Erasmus N., Denneau L., Heinze A.N., Flewelling H.,
Vanco R.
<Astron. Astrophys. 643, A59 (2020)>
=2020A&A...643A..59D 2020A&A...643A..59D (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets ; Photometry
Keywords: minor planets, asteroids: general - methods: data analysis -
techniques: photometric
Abstract:
The Asteroid Terrestrial-impact Last Alert System (ATLAS) is an
all-sky survey primarily aimed at detecting potentially hazardous
near-Earth asteroids. Apart from the astrometry of asteroids, it also
produces their photometric measurements that contain information about
asteroid rotation and their shape.
To increase the current number of asteroids with a known shape and
spin state, we reconstructed asteroid models from ATLAS photometry
that was available for approximately 180000 asteroids observed
between 2015 and 2018.
We made use of the light-curve inversion method implemented in the
Asteroids@home project to process ATLAS photometry for roughly 100000
asteroids with more than a hundred individual brightness measurements.
By scanning the period and pole parameter space, we selected those
best-fit models that were, according to our setup, a unique solution
for the inverse problem.
We derived ∼2750 unique models, 950 of them were already reconstructed
from other data and published. The remaining 1800 models are new.
About half of them are only partial models, with an unconstrained pole
ecliptic longitude. Together with the shape and spin, we also
determined for each modeled asteroid its color index from the cyan and
orange filter used by the ATLAS survey. We also show the correlations
between the color index, albedo, and slope of the phase-angle
function.
The current analysis is the first inversion of ATLAS asteroid
photometry, and it is the first step in exploiting the huge scientific
potential that ATLAS photometry has. ATLAS continues to observe, and
in the future, this data, together with other independent photometric
measurements, can be inverted to produce more refined asteroid models.
Description:
Table A.1: List of new asteroid models. For each asteroid, we list one
or two pole directions in the ecliptic coordinates (lambda, beta) with
uncertainties sigma_lambda and sigma_beta, the sidereal rotation
period P and its error sigma_P, the rotation period P_LCDB from the
LCDB and its quality code U (if available), the number of sparse
photometric data points in orange and cyan filters No, Nc,
respectively, the color c-o and its error sigma_c-o, and the method
which was used to derive the rotation period: C - convex models, E -
ellipsoids, CE - both methods gave the same unique period. The
accuracy of the sidereal rotation period P is of the order of the last
decimal place given. For some asteroids, the LCDB contains a note
about the rotation state or binarity: Here A means an ambiguous
period; B stands for a binary system; T means tumbling - a
non-principal-axis rotation; T0 means that the theoretical tumbling
damping time scale (Pravec et al., 2014Icar..233...48P 2014Icar..233...48P) is long enough
that tumbling might be expected, but observations are not sufficient
to substantiate either tumbling or not tumbling; T- means that the
tumbling damping time scale is long enough that tumbling might be
expected, but observations indicate that the object is not tumbling;
and T+ indicates that the tumbling damping time scale is short enough
that tumbling would not seem likely, however observations indicate
that it may be tumbling or actually is tumbling.
Table A.2: List of new asteroid models with period searched on a
limited interval. The meaning of columns is the same as in Table A.1.
Table A.3: List of partial models with the mean ecliptic pole latitude
beta and its dispersion Delta beta. The meaning of other columns is
the same as in Table A.1.
Table A.4: List of partial models with the mean ecliptic pole latitude
β and its dispersion Δβ, period searched on a limited
interval. The meaning of other columns is the same as in Table A.1
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 166 705 List of new models
tablea2.dat 166 191 List of new models - limited period interval
tablea3.dat 130 671 List of partial models
tablea4.dat 130 225 List of partial models - limited per. interval
--------------------------------------------------------------------------------
See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
Byte-by-byte Description of file: tablea1.dat tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 7 I6 --- Number Asteroid number
10- 29 A20 --- Name Asteroid name or designation
39- 41 I3 deg lambda1 Ecliptic pole longitude (J2000.0) for model 1
45- 46 I2 deg e_lambda1 Uncertainty of lambda1
51- 53 I3 deg beta1 Ecliptic pole latitude (J2000.0) for model 1
57- 58 I2 deg e_beta1 Uncertainty of beta1
63- 65 I3 deg lambda2 ? Ecliptic pole longitude (J2000.0) for model 2
69- 70 I2 deg e_lambda2 ? Uncertainty of lambda2
75- 77 I3 deg beta2 ? Ecliptic pole latitude (J2000.0) for model 2
81- 82 I2 deg e_beta2 ? Uncertainty of beta2
84- 93 F10.6 h P Sidereal period of rotation
95-103 F9.7 h e_P Uncertainty of P
106 A1 --- l_PLCDB Limit flag on PLCDB (G1)
107-117 F11.6 h PLCDB ? Rotation period in the LCDB (G1)
123-124 A2 --- U Uncertainty code according to LCDB (G1)
130-131 A2 --- Note Note according to LCDB (G1)
138-140 I3 --- No Number of photometric points in o filter
144-146 I3 --- Nc Number of photometric points in c filter
149-154 F6.3 mag o-c ? Color o-c
157-161 F5.3 mag e_o-c ? Uncertainty of color o-c
165-166 A2 --- Method Method used for period determination (G2)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat tablea4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 7 I6 --- Number Asteroid number
10- 29 A20 --- Name Asteroid name or designation
39- 41 I3 deg beta Ecliptic pole latitude (J2000.0)
45- 46 I2 deg e_beta Uncertainty of beta (Δβ)
48- 58 F11.6 h P Sidereal period of rotation
60- 67 F8.6 h e_P Uncertainty of P
70 A1 --- l_PLCDB Limit flag on PLCDB (G1)
71- 81 F11.6 h PLCDB ? Rotation period in the LCDB (G1)
87- 88 A2 --- U Uncertainty code according to LCDB (G1)
94- 95 A2 --- Note Note according to LCDB (G1)
102-104 I3 --- No Number of photometric points in o filter
108-110 I3 --- Nc Number of photometric points in c filter
114-118 F5.3 mag o-c ? Color o-c
121-125 F5.3 mag e_o-c ? Uncertainty of color o-c
129-130 A2 --- Method Method used for period determination (G2)
--------------------------------------------------------------------------------
Global notes:
Note (G1): LCDB for Lightcurve Database of Warner et al.
(2009, Icarus, 202, 134).
For U code, higher values meaning a more reliable period.
Note (G2): The method which was used to derive the unique rotation period
as follows:
C = convex inversion
E = ellipsoids
CE = both methods gave the same unique period
--------------------------------------------------------------------------------
Acknowledgements:
Josef Durech, durech(at)sirrah.troja.mff.cuni.cz
(End) Josef Durech [Charles University], Patricia Vannier [CDS] 25-Sep-2020