J/ApJ/784/110 NEOWISE observations of 105 near-Earth objects (Mainzer+, 2014)
The population of tiny near-earth objects observed by NEOWISE.
Mainzer A., Bauer J., Grav T., Masiero J., Cutri R.M., Wright E.,
Nugent C.R., Stevenson R., Clyne E., Cukrov G., Masci F.
<Astrophys. J., 784, 110 (2014)>
=2014ApJ...784..110M 2014ApJ...784..110M (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Minor planets ; Photometry, infrared
Keywords: atlases - catalogs - infrared: general -
minor planets, asteroids: general - surveys
Abstract:
Only a very small fraction of the asteroid population at size scales
comparable to the object that exploded over Chelyabinsk, Russia has
been discovered to date, and physical properties are poorly
characterized. We present previously unreported detections of 105
close approaching near-Earth objects (NEOs) by the Wide-field Infrared
Survey Explorer (WISE) mission's NEOWISE project. These infrared
observations constrain physical properties such as diameter and albedo
for these objects, many of which are found to be smaller than 100m.
Because these objects are intrinsically faint, they were detected by
WISE during very close approaches to the Earth, often at large
apparent on-sky velocities. We observe a trend of increasing albedo
with decreasing size, but as this sample of NEOs was discovered by
visible light surveys, it is likely that selection biases against
finding small, dark NEOs influence this finding.
Description:
The Wide-field Infrared Survey Explorer (WISE) instrument used three
beamsplitters to collect images in all four bands simultaneously (3.4,
4.6, 12 and 22µm, denoted as W1, W2, W3, and W4, respectively). The
exposure time in all four WISE bands was set to 8.8s in bands W3 and
W4 and 7.7s in bands W1 and W2.
We report the detection by Wide-field Infrared Survey Explorer (WISE)
mission's NEOWISE project of an additional 105 Near-Earth Objects
(NEOs) that were discovered by ground-based visible light surveys and
made very close approaches to the Earth while WISE was observing.
These objects tend to be small and fast-moving. This sample represents
a pilot study for a future effort to conduct a wholesale search of the
NEOWISE databases and images for the entire set of known minor
planets; this effort will be carried out by the NEOWISE project in the
near future.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 93 355 Observed WISE magnitudes for each of the
Near-Earth Objects (NEOs) presented here,
including the Modified Julian Date (MJD)
table2.dat 77 107 *Thermal fit results for the 105 new NEO
detections reported in this work
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Note on table2.dat: This table contains the preliminary thermal fit results
based on the First-Pass version of the Wide-field Infrared Survey Explorer
(WISE) data processing as described in the text.
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
II/328 : AllWISE Data Release (Cutri+ 2013)
J/ApJ/814/117 : NEOWISE Reactivation mission: 1st yr data (Nugent+, 2015)
J/ApJ/770/7 : WISE/NEOWISE Main Belt asteroids (Masiero+, 2013)
J/ApJ/760/L12 : WISE/NEOWISE NEOs preliminary thermal fits (Mainzer+, 2012)
J/ApJ/759/L8 : WISE/NEOWISE obs. of main belt asteroids (Masiero+, 2012)
J/ApJ/759/49 : Jovian Trojan asteroids with WISE/NEOWISE (Grav+, 2012)
J/ApJ/744/197 : WISE/NEOWISE observations of Hilda asteroids (Grav+, 2012)
J/ApJ/743/156 : NEOWISE obs. of NEOs: preliminary results (Mainzer+, 2011)
J/ApJ/742/40 : Jovian Trojans asteroids with WISE/NEOWISE (Grav+, 2011)
J/ApJ/741/68 : Main Belt asteroids with WISE/NEOWISE. I. (Masiero+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Source name
8 A1 --- f_Name [*] Flag on Name (*=stacked object) (1)
10- 22 F13.7 d MJD [55203.4/55571.4] Modified Julian Date of
observation
24 A1 --- l_W1mag [>] The 2σ upper limit flag on W1mag (2)
25- 31 F7.3 mag W1mag [10.8/17.3] WISE 3.4µm band magnitude
33- 37 F5.3 mag e_W1mag [0.02/0.52]? Uncertainty in W1mag
39 A1 --- l_W2mag [>] The 2σ upper limit flag on W2mag (2)
40- 46 F7.3 mag W2mag [7.9/15.8] WISE 4.6µm band magnitude
48- 52 F5.3 mag e_W2mag [0.009/0.54]? Uncertainty in W2mag
54 A1 --- l_W3mag [>] The 2σ upper limit flag on W3mag (2)
55- 61 F7.3 mag W3mag [3.2/12.3]? WISE 12µm band magnitude (3)
63- 67 F5.3 mag e_W3mag [0.01/0.53]? Uncertainty in W3mag
69 A1 --- l_W4mag [>] The 2σ upper limit flag on W4mag (2)
70- 75 F6.3 mag W4mag [1.4/8.3]? WISE 22µm band magnitude (3)
77- 81 F5.3 mag e_W4mag [0.017/0.52]? Uncertainty in W4mag
83- 93 A11 arcsec Ap Aperture code (0=pipeline profile fit
photometry was used) (4)
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Note (1): Data was stacked in order to recover the fluxes thus the stacked image
photometry is reported.
Note (2): Objects that were not detected at a particular wavelength represent
2σ upper limits (Cutri et al. 2012wise.rept....1C).
Note (3): Blank indicates no data available at that wavelength.
Note (4): The aperture radius for each WISE band.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Source name (1)
9- 18 A10 --- OName Object name (packed designation) (1)
20- 24 F5.2 mag HMag [16.6/27.4]? Absolute H band magnitude (1)
26- 29 F4.2 --- G [0.15] Phase curve slope parameter (1)
31- 35 F5.3 km Diam [0.008/1.9] Diameter (D) (1)
37- 41 F5.3 km e_Diam [0.001/0.41] The 1σ uncertainty in Diam
43- 47 F5.3 --- pV [0.01/0.61]? Visible albedo (pV) (1)
49- 53 F5.3 --- e_pV [0/0.33]? The 1σ uncertainty in pV
55- 59 F5.3 --- eta [0.75/3.2] Beaming parameter (η) (1)
61- 65 F5.3 --- e_eta [0.025/0.61] The 1σ uncertainty in eta
67- 71 F5.3 --- pIR [0.01/0.93] Infrared albedo (pIR) (1)
73- 77 F5.3 --- e_pIR [0/0.43] The 1σ uncertainty in pIR
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Note (1): The 1σ errors presented here were statistically generated using
Monte Carlo modeling. WISE fluxes, absolute magnitude H and G were varied
by their 1σ error bars, as well as beaming and pIR when these two
parameters could not be fit. The quoted precision for each parameter
follows the object with the most significant figures for the error on that
value in the table. The statistical errors on diameter and pV for each
object in the table should be added in quadrature to the systematic errors
described in the text and discussed in Mainzer et al.
(2011ApJ...736..100M 2011ApJ...736..100M). If η=π, the Fast Rotating Model (FRM;
Lebofsky et al. 1978Icar...35..336L 1978Icar...35..336L, Lebofsky & Spencer
1989aste.conf..128L, Veeder et al. 1978AJ.....83..651V 1978AJ.....83..651V) was used instead of
the Near-Earth Asteroid Thermal Model (NEATM; Harris 1998Icar..131..291H 1998Icar..131..291H).
Objects with multiple entries were observed at multiple epochs, which were
fit separately.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 03-Aug-2016