J/AJ/159/92 Yarkovsky drift measurements for NEAs (Greenberg+, 2020)
Yarkovsky drift detections for 247 Near-Earth Asteroids.
Greenberg A.H., Margot J.-L., Verma A.K., Taylor P.A., Hodge S.E.
<Astron. J., 159, 92 (2020)>
=2020AJ....159...92G 2020AJ....159...92G
ADC_Keywords: Minor planets; Optical; Radio sources
Keywords: Asteroids ; The Sun ; Orbit determination ; Astrometry
Abstract:
The Yarkovsky effect is a thermal process acting upon the orbits of
small celestial bodies, which can cause these orbits to slowly expand
or contract with time. The effect is subtle (<da/dt≳10-4au/My for a
1km diameter object) and is thus generally difficult to measure. We
analyzed both optical and radar astrometry for 600 Near-Earth
Asteroids (NEAs) for the purpose of detecting and quantifying the
Yarkovsky effect. We present 247 NEAs with measured drift rates, which
is the largest published set of Yarkovsky detections. This large
sample size provides an opportunity to examine the Yarkovsky effect in
a statistical manner. In particular, we describe two independent
population-based tests that verify the measurement of Yarkovsky
orbital drift. First, we provide observational confirmation for the
Yarkovsky effect's theoretical size dependence of 1/D, where D is
diameter. Second, we find that the observed ratio of negative to
positive drift rates in our sample is 2.34, which, accounting for bias
and sampling uncertainty, implies an actual ratio of 2.7-0.7+0.3.
This ratio has a vanishingly small probability of occurring due to
chance or statistical noise. The observed ratio of retrograde to
prograde rotators is two times lower than the ratio expected from
numerical predictions from NEA population studies and traditional
assumptions about the sense of rotation of NEAs originating from
various main belt escape routes. We also examine the efficiency with
which solar energy is converted into orbital energy and find a median
efficiency in our sample of 12%. We interpret this efficiency in terms
of NEA spin and thermal properties.
Description:
We considered four sets of Yarkovsky detection candidates.
Two sets of candidates, the Nugent12 set and the Farnocchia13 set,
represent Yarkovsky detections reported by
Nugent+, 2012AJ....144...60N 2012AJ....144...60N and Farnocchia+, 2013Icar..224....1F 2013Icar..224....1F,
respectively. For these objects, we performed our analysis in two
ways-first, by using the same observational data as those used by
the authors, and second, by using all currently available data
(Section 5.2).
The third set contains objects that had not previously been considered
by the other two works but that we determined to be Yarkovsky
detection candidates. For the most part, these objects had either not
yet been discovered, or had small observation intervals prior to 2012
or early 2013.
The fourth and final set includes 24 additional objects of particular
interest, including 22 numbered binary asteroids.
Optical astrometry was automatically downloaded from the Minor Planet
Center (MPC) on 2019 November 11. The number of optical observations
considered in this work is 379,434. Each optical observation yields
two measurements of position on the plane of the sky.
Radar astrometry was downloaded from the JPL Radar Astrometry Database
and was discarded from MPC records to avoid duplication. In a few
instances, previously unpublished radar data obtained by the authors
were also used. The radar data considered in this work include 735
range measurements and 412 Doppler measurements.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 119 247 Yarkovsky drift measurements for 247 Near-Earth
Asteroids (NEAs)
table2.dat 119 8 Yarkovsky drift measurements for 8 Near-Earth
Asteroids whose rates require additional
verifications because solutions that include
pre-1965 astrometry differ from solutions that
exclude pre-1965 astrometry
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
J/A+A/509/A27 : Near-Earth asteroids & QSOs close approaches (Nedelcu+,2010)
J/A+A/511/A40 : Near Earth Asteroids positions (Birlan+, 2010)
J/A+A/550/L11 : LCs of Near-Earth Asteroid 162173 (1999 JU3) (Kim+ 2013)
J/ApJ/784/110 : NEOWISE obs. of 105 near-Earth objects (Mainzer+, 2014)
J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)
J/AJ/152/163 : Mission Accessible Near-Earth Objects Survey (Thirouin+, 2016)
J/AJ/154/162 : KMTNet-SAAO obs. of near-Earth asteroids (Erasmus+, 2017)
J/MNRAS/469/4400 : Veritas family members Yarkovsky drift rates (Carruba+,2017)
J/ApJ/864/L33 : Polarimetric survey of Phaethon with PICO (Shinnaka+, 2018)
J/ApJS/239/4 : Near-Earth Object Survey (MANOS): 4yrs phot. (Thirouin+, 2018)
J/A+A/609/A105 : 280 one-opposition near Earth asteroids (Vaduvescu+, 2018)
J/A+A/619/A123 : LCs of Near-Earth Asteroid 3200 Phaethon (Kim+ 2018)
J/A+A/627/A124 : INT near-Earth asteroids spectro. survey (Popescu+, 2019)
J/A+A/627/A172 : Near-Earth asteroid (1917) Cuyo opt. & IR obs. (Rozek+,2019)
J/AJ/158/196 : Near-Earth Object Survey (MANOS) spectro. (Devogele+, 2019)
http://minorplanetcenter.net/ : Minor Planet Center home page
http://ssd.jpl.nasa.gov/?radar : Radar astrometry from JPL home page
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- Planet [433/526798]? Asteroid number
8- 24 A17 --- Name Asteroid identifier
26- 32 A7 --- f_Name Flag(s) on Name (1)
34- 37 F4.2 au a [0.64/2.68] Semi-major axis
39- 42 F4.2 --- e [0.03/0.91] Orbital eccentricity
44 A1 --- f_Diam Flag on Diam (2)
46- 50 F5.2 km Diam [0.01/37.7] Diameter
52- 56 I5 --- No [96/16850] Number of optical
measurements used in the solution
58- 59 I2 --- Nr [0/51] Number of radar measurements used
in the solution
61- 67 F7.2 10-4au/Myr da/dt-o [-382/57] Orbit-averaged drift in
semi-major axis (optical)
69- 73 F5.1 10-4au/Myr e_da/dt-o [0.2/170] One-standard-deviation in da/dt
75- 79 E5.0 10-4au/Myr p-o [1e-16/1.0] The p-value (optical) (3)
81- 87 F7.2 10-4au/Myr da/dt-r [-320/49]? Orbit-averaged drift in
semi-major axis (optical+radar)
89- 93 F5.1 10-4au/Myr e_da/dt-r [0.1/157]? One-standard-deviation in
da/dt-r
95- 99 E5.0 10-4au/Myr p-r [1e-16/0.05]? The p-value
(optical+radar) (3)
101-104 F4.1 --- sY [-1/66.3] Yarkovsky sensitivity parameter
from Nuget+, 2012AJ....144...60N 2012AJ....144...60N
106-109 F4.2 --- xi [0.01/4.2] The Yarkovsky efficiency
ξ (4)
111-114 I4 yr Obs.Y-s [1900/2011] Years of the observation arc
start
116-119 I4 yr Obs.Y-e [2004/2019] Years of the observation arc
end
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Note (1): Flags as follows:
B = Binary or triple asteroid
S = Anormalously high ξ value, ξ>0.5
D = Yarkovsky detection predicted to be weaker due to the time span or
quantity of astrometry (Section 5.1)
Note (2): Flags as follows:
* = Diameter inferred from H-magnitude via Equation 13 when the taxonomic
type is not available from the Small Body Database
T = Diameter inferred from H-magnitude via Equation 13 when the taxonomic
type is available from the Small Body Database
Note (3): Used in distinguishing between a gravity-only dynamical model and a
Yarkovsky dynamical model using optical data only, p, and optical
plus radar data, pr.
Note (4): Which was computed with a bulk density that was extracted from the
Small Body Database, if available, or inferred from the spectral
type, if available (Section 10).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 21-Apr-2020