J/AJ/169/256 Near Earth Objects fluxes & periods from Spitzer/IRAC (Hora+, 2025)
Infrared Fluxes and Lightcurves of Near-Earth Objects: The Full Spitzer Sample.
Hora J.L., Allen A.J., Trilling D.E., Smith H.A., McNeill A.
<Astron. J., 169, 256 (2025)>
=2025AJ....169..256H 2025AJ....169..256H
ADC_Keywords: Minor planets; Photometry, infrared; Nonstellar objects;
Keywords: Near-Earth objects ; Asteroid rotation
Abstract:
The IRAC camera on the Spitzer Space Telescope observed 2175 near-Earth
objects (NEOs) during its Warm Mission phase, primarily in three large
surveys, and also in a small number of a dedicated projects. In this
paper, we present the final reprocessing of the NEO data and determine
fluxes at 3.6um (where available) and 4.5um. The observing windows
range from minutes to nearly 10 hours, which means that, for 39 NEOs,
we observe a complete lightcurve, and for these objects, we present
period and amplitude estimates and derive minimum cohesive strengths
for the objects with well-determined periods. For an additional
128 objects, we detect a significant fraction of a complete lightcurve
and present estimated lower limits to their rotation periods. This
paper presents the final and definitive Spitzer/IRAC NEO flux catalog.
Description:
The data set was obtained with the Infrared Array Camera (IRAC) on the
Spitzer Space Telescope, a space-based observatory in heliocentric
orbit. All observations were carried out during Spitzer's Warm
Mission (i.e., after the cryogen was exhausted in 2009) and were
grouped mainly into three large survey programs as well as a handful
of smaller, targeted projects. The principal surveys are commonly
referred to as the ExploreNEOs, NEO Survey, and NEO Legacy Survey,
while the dedicated effort is known as the Physical Characterization
of NEOs program.
IRAC was operated in its two surviving channels, delivering photometry
at 3.6um (Band 1) and 4.5um (Band 2). Note that the 3.6 and 4.5um
fields of view do not overlap in the Spitzer focal plane, so the NEO
could not be observed simultaneously in both bands. The catalog
ultimately contains flux measurements for 2175 near-Earth objects,
with observing windows ranging from a few minutes up to nearly ten
hours.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
neo.dat 42 2111 List of Near Earth Objects observed with
Spitzer/IRAC (table added by CDS)
table2.dat 102 2248 IRAC Fluxes from Mosaics for all NEOs Observed
table3.dat 62 13 Periods Determined from IRAC Observations
table4.dat 64 26 NEO Under-Constrained Periods (<2 Full Periods
Sampled or >10% FAP)
table5.dat 53 124 NEO Period Lower Limits (<1 Full Period Sampled)
lc.dat 53 2922 Interactive NEO light curves and link to the
individual MRT file (table added by CDS)
lc_files/* . 2922 Individual MRT file of the NEO light curves
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See also:
J/ApJ/743/156 : NEOWISE obs. of NEOs: preliminary results (Mainzer+, 2011)
J/ApJS/239/4 : Near-Earth Object Survey (MANOS): 4yrs phot. (Thirouin+, 2018)
http://www.minorplanetcenter.net/ : IAU Minor Planet Center website
http://ssd.jpl.nasa.gov/sb/ : Jet Propulsion Lab Small-Body database
Byte-by-byte Description of file: neo.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Provisional Designation
12- 19 I8 --- SPKID [3001703/20752877] Jet Propulsion Lab
Small-Body Database identifier SPK-ID
21- 42 A22 --- MPC Minor Planet Center designation
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Byte-by-byte Description of file: lc.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- SPKID [3001703/20761121] Jet Propulsion Lab
Small-Body Database identifier SPK-ID
10- 17 I8 --- AORKEY Spitzer AORKEY value (1)
19 I1 --- Ch Spitzer/IRAC Channel (1=3.6um, 2=4.5um) (2)
21- 22 A2 --- LC Associated light curve with link to the
interactive plot
24- 48 A25 --- File Link to the light curve file in MRT format
50- 53 I4 --- nFlux [2/5115] Number of flux measurements in this
light curve
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Note (1): The AORKEY uniquely identifies a single Spitzer observation sequence,
which is called an Astronomical Observation Request, or AOR.
Note (2): Channels as follows:
1 = 3.6um IRAC band (670 occurrences)
2 = 4.5um IRAC band (2252 occurrences)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Provisional Designation
12- 19 I8 --- SPKID [3001703/20752877] Jet Propulsion Lab
Small-Body Database identifier SPK-ID
21- 42 A22 --- MPC Minor Planet Center designation
44- 54 F11.5 d MJD [55040/58817] Modified Julian Date of
observation start, JD-2400000.5
56- 60 F5.3 h Dur [0.054/9.134] Duration of observation
62- 69 F8.2 uJy Flux1 [-4.71/92278]? Spitzer/IRAC Channel 1 (3.6um)
flux
71- 77 F7.2 uJy e_Flux1 [0.3/1005.5]? Flux1 uncertainty
79- 87 F9.2 uJy Flux2 [1.4/216178] Spitzer/IRAC Channel 2 (4.5um)
flux
89- 95 F7.2 uJy e_Flux2 [0.37/5963.8] Flux2 uncertainty
97- 100 F4.2 --- Amp2 [0.01/1.43]? Spitzer/IRAC Channel 2 (4.5um)
flux amplitude ratio; (max-min)/median
102 A1 --- Note Note (1)
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Note (1): Reduction note as follows:
1 = Objects with small relative motion during the observation; 5 occurrences
2 = Objects that passed near a bright star during the observation;
2 occurrences
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Provisional Designation
12- 16 F5.3 h Per [0.1/3.98] Derived rotation period
18- 22 F5.3 h e_Per [0/0.04] Uncertainty in Per
24- 31 E8.2 --- FAP [0/0.078] False Alarm Probability
33- 37 F5.2 --- nPer [2.25/17.56] Number of periods sampled
39- 42 I4 --- nFrame [26/5115] Number of IRAC frames
44- 55 F12.6 d MJDstart [55726/58383] MJD of first
frame, JD-2400000.5
57- 62 F6.3 h Dur [0.34/10.18] Duration of observation
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Provisional Designation
12- 16 F5.3 h Per [0.11/6.42] Derived rotation period
18- 22 F5.3 h e_Per [0.012/0.31] Uncertainty in Per
24 A1 --- l_FAP [<] FAP<1e-60 (added by CDS)
26- 33 E8.2 --- FAP [6e-83/1]? False Alarm Probability
35- 39 F5.2 --- nPer [0.93/4.41] Number of periods sampled
41- 44 I4 --- nFrame [43/403] Number of IRAC frames
46- 57 F12.6 d MJDstart [55724/58433] MJD of first frame
59- 64 F6.3 h Dur [0.3/9.1] Duration of observation
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Provisional Designation
12- 15 F4.1 h lPer [0.4/13] Rotation period Lower Limit
17 A1 --- l_FAP [<] FAP<1e-32 (added by CDS)
19- 26 E8.2 --- FAP [3e-99/0.012]? False Alarm Probability
28- 31 F4.2 --- nPer [0.25/2.5] Approximate number of periods
33- 35 I3 --- nFrame [17/933] Number of IRAC frames used
37- 48 F12.6 d MJDstart [55201/58808] Start MJD of
first frame, JD-2400000.5
50- 53 F4.2 h Dur [0.33/9.1] Duration of observation
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 11-Feb-2026