J/A+A/610/A7 Photometry and models of long-period asteroids (Marciniak+, 2018)
Photometric survey, modelling, and scaling of long-period and low-amplitude
asteroids.
Marciniak A., Bartczak P., Mueller T., Sanabria J.J., Ali-Lagoa V.,
Antonini P., Behrend R., Bernasconi L., Bronikowska M., Butkiewicz-Bkak M.,
Cikota A., Crippa R., Ditteon R., Dudzinski G., Duffard R., Dziadura K.,
Fauvaud S., Geier S., Hirsch R., Horbowicz J., Hren M., Jerosimic L.,
Kaminski K., Kankiewicz P., Konstanciak I., Korlevic P., Kosturkiewicz E.,
Kudak V., Manzini F., Morales N., Murawiecka M., Ogloza W., Oszkiewicz D.,
Pilcher F., Polakis T., Poncy R., Santana-Ros T., Siwak M., Skiff B.,
Sobkowiak K., Stoss R., Zejmo M., Zukowski K.
<Astron. Astrophys. 610, A7 (2018)>
=2018A&A...610A...7M 2018A&A...610A...7M (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets ; Photometry
Keywords: techniques: photometric - minor planets: asteroids
Abstract:
The available set of spin and shape modelled asteroids is strongly
biased against slowly rotating targets and those with low lightcurve
amplitudes. This is due to the observing selection effects. As a
consequence, the current picture of asteroid spin axis distribution,
rotation rates, radiometric properties, or aspects related to the
object's internal structure might be affected too.
To counteract these selection effects, we are running a photometric
campaign of a large sample of main belt asteroids omitted in most
previous studies. Using least chi-squared fitting we determined
synodic rotation periods and verified previous determinations. When a
dataset for a given target was sufficiently large and varied, we
performed spin and shape modelling with two different methods to
compare their performance.
We used the convex inversion method and the non-convex SAGE algorithm,
applied on the same datasets of dense lightcurves. Both methods search
for the lowest deviations between observed and modelled lightcurves,
though using different approaches. Unlike convex inversion, the SAGE
method allows for the existence of valleys and indentations on the
shapes based only on lightcurves.
We obtain detailed spin and shape models for the first five targets of
our sample: (159) Aemilia, (227) Philosophia, (329) Svea, (478)
Tergeste, and (487) Venetia. When compared to stellar occultation
chords, our models obtained an absolute size scale and major
topographic features of the shape models were also confirmed. When
applied to thermophysical modelling (TPM), they provided a very good
fit to the infrared data and allowed their size, albedo, and thermal
inertia to be determined.
Convex and non-convex shape models provide comparable fits to
lightcurves. However, some non-convex models fit notably better to
stellar occultation chords and to infrared data in sophisticated
thermophysical modelling (TPM). In some cases TPM showed strong
preference for one of the spin and shape solutions. Also, we confirmed
that slowly rotating asteroids tend to have higher-than-average values
of thermal inertia, which might be caused by properties of the surface
layers underlying the skin depth.
Description:
The files contain asteroid brightness and geometry for corresponding
epochs. The "*lcs" files were used for obtaining shape models and spin
states of the asteroids using multi-apparition data. Individual
lightcurves within a file are separated by an empty line, all
lightcurves are relative.
The "*data" files contain the data used for finding the period and
contain lightcurves from only one apparition. Here data are relative
as well, except for 932 Hooveria and 830 Petropolitana, where all data
were calibrated data using CMC15, APASS and GAIA catalogue stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 71 11 Synodic periods and amplitude values found within
this project compared to literature data
gathered previously in LCDB
159lcs.dat 112 1455 Asteroid 159 Aemilia individual lightcurves
227lcs.dat 112 2243 Asteroid 227 Philosophia individual lightcurves
329lcs.dat 112 1839 Asteroid 329 Svea individual lightcurves
478lcs.dat 112 1364 Asteroid 478 Tergeste individual lightcurves
487lcs.dat 112 1329 Asteroid 487 Venetia individual lightcurves
551data.dat 22 533 Asteroid 551 Ortrud individual lightcurves
581data.dat 22 224 Asteroid 581 Tauntonia individual lightcurves
830data.dat 22 814 Asteroid 830 Petropolitana individual lightcurves
923data.dat 22 216 Asteroid 923 Herluga individual lightcurves
932data.dat 22 584 Asteroid 932 Hooveria individual lightcurves
995data.dat 22 802 Asteroid 995 Sternberga individual lightcurves
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
J/A+A/465/331 : Asteroid brightness and geometry (Durech+, 2007)
J/A+A/498/313 : Photometry of 3 main belt asteroids (Marciniak+, 2009)
J/A+A/508/1503 : Photometry of 3 main belt asteroids (Marciniak+, 2009)
J/A+A/529/A107 : Photometry of 4 main belt asteroids (Marciniak+, 2011)
J/A+A/545/A131 : Photometry of 8 main belt asteroids (Marciniak+, 2012)
J/A+A/546/A72 : Light curves of Flora region asteroids (Kryszczynska+, 2012)
J/A+A/598/A63 : 2015 TB145 light curve (Mueller+, 2017)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Asteroid name
22- 30 A9 --- Amp Amplitude (LCDB and this work)
32- 37 F6.3 h PerLCBD LCBD period
40- 41 A2 --- q_PerLCBD Period quality code
43- 49 F7.3 h Per Period (this work)
51- 55 F5.3 h e_Per rms uncertainty on Per
57 A1 --- n_Per [*] * for period determinations substantially
differing from previously accepted values
59 A1 --- Note [nm] n for Targets with new periods,
m for Targets with models
61- 71 A11 --- FileName Name of the tabel with light curve data
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Byte-by-byte Description of file: *lcs.dat
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Bytes Format Units Label Explanations
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2- 15 F14.6 d JD JD epoch corrected for the light-time
corresponding to the Earth-asteroid distance
17- 28 E12.6 --- br Relative brightness in intensity units,
mean brightness of each lightcurve is unity
30- 42 E13.6 AU Sx x component of the vector from the asteroid to
the Sun in J2000 ecliptic Cartesian coordinates
44- 56 E13.6 AU Sy y component of the vector from the asteroid to
the Sun in J2000 ecliptic Cartesian coordinates
58- 70 E13.6 AU Sz z component of the vector from the asteroid to
the Sun in J2000 ecliptic Cartesian coordinates
72- 84 E13.6 AU Ex x component of the vector from the asteroid to
the Earth in J2000 ecliptic Cartesian coordinates
86- 98 E13.6 AU Ey y component of the vector from the asteroid to
the Earth in J2000 ecliptic Cartesian coordinates
100-112 E13.6 AU Ez z component of the vector from the asteroid to
the Earth in J2000 ecliptic Cartesian coordinates
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Byte-by-byte Description of file: *data.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 15 F14.6 d JD JD epoch corrected for the light-time
corresponding to the Earth-asteroid distance
17- 22 F6.3 mag br Brightness in magnitude units
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Acknowledgements:
Anna Marciniak, am(at)amu.edu.pl
(End) Patricia Vannier [CDS] 20-Oct-2017