J/ApJ/742/40 Jovian Trojans asteroids with WISE/NEOWISE (Grav+, 2011)
WISE/NEOWISE observations of the Jovian Trojans: preliminary results.
Grav T., Mainzer A.K., Bauer J., Masiero J., Spahr T., McMillan R.S.,
Walker R., Cutri R., Wright E., Eisenhardt P.R.M., Blauvelt E., Debaun E.,
Elsbury D., Gautier Iv T., Gomillion S., Hand E., Wilkins A.
<Astrophys. J., 742, 40 (2011)>
=2011ApJ...742...40G 2011ApJ...742...40G
ADC_Keywords: Infrared sources ; Minor planets ; Surveys
Keywords: infrared: planetary systems - minor planets, asteroids: general -
surveys
Abstract:
We present the preliminary analysis of over 1739 known and 349
candidate Jovian Trojans observed by the NEOWISE component of the
Wide-field Infrared Survey Explorer (WISE). With this survey the
available diameters, albedos, and beaming parameters for the Jovian
Trojans have been increased by more than an order of magnitude
compared to previous surveys. We find that the Jovian Trojan
population is very homogenous for sizes larger than ∼10km (close to
the detection limit of WISE for these objects). The observed sample
consists almost exclusively of low albedo objects, having a mean
albedo value of 0.07±0.03. The beaming parameter was also derived
for a large fraction of the observed sample, and it is also very
homogenous with an observed mean value of 0.88±0.13. Preliminary
debiasing of the survey shows that our observed sample is consistent
with the leading cloud containing more objects than the trailing
cloud. We estimate the fraction to be N(leading)/N(trailing)
∼1.4±0.2, lower than the 1.6±0.1 value derived by Szabo et al.
(2007MNRAS.377.1393S 2007MNRAS.377.1393S).
Description:
WISE is a NASA Medium-class Explorer mission designed to survey the
entire sky in four infrared wavelengths, 3.4, 4.6, 12, and 22um
(denoted W1, W2, W3, and W4, respectively). The survey collected
observations of over 157000 asteroids, including Jupiter Trojans. The
survey started on 2010 January 14 and the mission exhausted its
secondary tank cryogen on 2010 August 5. After the exhaustion of the
primary cryogen tank on 2010 September 29, the survey was continued
until 2011 February 1 as the NEOWISE Post-Cryogenic Mission using only
bands W1 and W2.
The WISE observations of the Trojans were retrieved by querying the
Minor Planet Center (MPC) observation files to look for all instances
of individual WISE detections of the desired objects that were
reported using the WISE Moving Object Processing System (WMOPS;
Mainzer et al. 2011ApJ...731...53M 2011ApJ...731...53M).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 79 1742 *Thermal model fits
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Note on table1.dat: This table contains the preliminary thermal fit results
based on the First Pass version of the WISE data processing as described in
the text. The NEOWISE project plans to produce an updated final catalog
of physical properties based on the Second Pass processing of the WISE
data using the updated version of the WISE Science Data System, with a
goal of delivering this updated catalog to NASA's Planetary Data System.
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2013)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
J/ApJ/741/68 : Main Belt asteroids with WISE/NEOWISE. I. (Masiero+, 2011)
J/ApJ/743/156 : NEOWISE obs. of NEOs: preliminary results (Mainzer+, 2011)
J/AJ/134/1133 : Fraction of contact binary Trojan asteroids (Mann+, 2007)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- MPC Trojan name; MPC format
9- 13 F5.2 mag HMag Absolute H band magnitude
15- 18 F4.2 --- G Magnitude slope parameter
20- 25 F6.2 km Diam Diameter
27- 31 F5.2 km e_Diam Statistical error in Diam (1)
33- 37 F5.3 --- pV Optical geometrical albedo
39- 43 F5.3 --- e_pV Statistical error in pV (1)
45- 49 F5.3 --- eta [0.5/1.5] Beaming parameter η
(takes into account the thermal inertia)
51- 55 F5.3 --- e_eta Statistical error in eta (1)
57- 61 F5.3 --- pIR Infra-red geometrical albedo
63- 67 F5.3 --- e_pIR Statistical error in pIR (1)
69- 70 I2 --- NW1 Number of WISE W1 band (3.4um) observations
72- 73 I2 --- NW2 Number of WISE W2 band (4.6um) observations
75- 76 I2 --- NW3 Number of WISE W3 band (12um) observations
78- 79 I2 --- NW4 Number of WISE W4 band (22um) observations
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Note (1): Error values presented here represent the statistical errors
on the model fits, including Monte Carlo modeling of uncertainties
for the WISE magnitudes, H, G, and beaming and pIR when these two
parameters cannot be fit. Two calibration papers by Mainzer et al.
(2011ApJ...731...53M 2011ApJ...731...53M and 2011ApJ...737L...9M 2011ApJ...737L...9M) discuss the absolute
calibration of the WISE data for small Solar system bodies and should
be consulted before comparing with data derived from other sources.
The quoted precision for each parameter follows the object with the
most significant figures for the error on that value in the table.
Readers are encouraged to check the WISE Explanatory Supplement
http://wise2.ipac.caltech.edu/docs/release/prelim/expsup/wise_prelrel_toc.html
(Cutri et al. 2011wise.rept....1C) for details and updates.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 17-Apr-2013