J/AJ/154/76 Masses of 30 large subject asteroids (Baer+, 2017)
Simultaneous mass determination for gravitationally coupled asteroids.
Baer J., Chesley S.R.
<Astron. J., 154, 76-76 (2017)>
=2017AJ....154...76B 2017AJ....154...76B (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets
Keywords: astrometry - celestial mechanics - ephemerides
Abstract:
The conventional least-squares asteroid mass determination algorithm
allows us to solve for the mass of a large subject asteroid that is
perturbing the trajectory of a smaller test asteroid. However, this
algorithm is necessarily a first approximation, ignoring the
possibility that the subject asteroid may itself be perturbed by the
test asteroid, or that the encounter's precise geometry may be
entangled with encounters involving other asteroids. After reviewing
the conventional algorithm, we use it to calculate the masses of 30
main-belt asteroids. Compared to our previous results, we find new
mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51
Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532
Herculina) and significantly more precise estimates for six others (2
Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However,
we also find that the conventional algorithm yields questionable
results in several gravitationally coupled cases. To address such
cases, we describe a new algorithm that allows the epoch state vectors
of the subject asteroids to be included as solve-for parameters,
allowing for the simultaneous solution of the masses and epoch state
vectors of multiple subject and test asteroids. We then apply this
algorithm to the same 30 main-belt asteroids and conclude that mass
determinations resulting from current and future high-precision
astrometric sources (such as Gaia) should conduct a thorough search
for possible gravitational couplings and account for their effects.
Description:
Our variational analysis yielded the 228 valid mass determinations for
30 large subject asteroids listed in Table1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ast.dat 14 30 Large subject asteroids
table1.dat 42 251 Masses measured using the traditional method
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
Byte-by-byte Description of file: ast.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Ast [1/804] Subject asteriod number
5- 14 A10 --- Name Subject asteriod name
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Ast [1/804] Subject asteriod number
5- 11 A7 --- Test Test asteriod identifier (Average=weighted
average mass)
13- 21 E9.3 Msun Mass [5.6e-13/4.78e-10] Measured mass
23- 30 E8.2 Msun e_Mass [4.58e-14/7.77e-11] Standard deviation in Mass
32- 36 F5.3 arcsec rms [0.292/0.681]? RMS observational error
38- 42 F5.1 --- Signi [2.1/707.9] Significance
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 09-Nov-2017