J/ApJS/239/4 Near-Earth Object Survey (MANOS): 4yrs photometry (Thirouin+, 2018)
The Mission Accessible Near-Earth Objects Survey: four years of photometry.
Thirouin A., Moskovitz N.A., Binzel R.P., Christensen E.J., DeMeo F.E.,
Person M.J., Polishook D., Thomas C.A., Trilling D., Willman M.C., Burt B.,
Hinkle M.L., Pugh T.
<Astrophys. J. Suppl. Ser., 239, 4 (2018)>
=2018ApJS..239....4T 2018ApJS..239....4T
ADC_Keywords: Minor planets; Photometry
Keywords: minor planets, asteroids: general
Abstract:
Over 4.5 years, the Mission Accessible Near-Earth Object Survey
assembled 228 near-Earth object (NEO) light curves. We report
rotational light curves for 82 NEOs, constraints on amplitudes and
periods for 21 NEOs, light curves with no detected variability within
the image signal-to-noise and length of our observing block for 30
NEOs, and 10 tumblers. We uncovered two ultra-rapid rotators with
periods below 20s,--2016 MA with a potential rotational periodicity of
18.4s, and 2017 QG18 rotating in 11.9s--and estimated the fraction of
fast/ultra-rapid rotators undetected in our project plus the
percentage of NEOs with a moderate/long periodicity undetectable
during our typical observing blocks. We summarize the findings of a
simple model of synthetic NEOs to infer the object's morphology
distribution using the measured distribution of light curve
amplitudes. This model suggests that a uniform distribution of axis
ratio can reproduce the observed sample. This suggests that the
quantity of spherical NEOs (e.g., Bennu) is almost equivalent to the
quantity of highly elongated objects (e.g., Itokawa), a result that
can be directly tested thanks to shape models from Doppler delay radar
imaging analysis. Finally, we fully characterized two NEOs-2013 YS2
and 2014 FA7-as appropriate targets for a potential robotic/human
mission due to their moderate spin periods and low Δv.
Description:
In approximately 4.5 years, Mission Accessible Near-Earth Object
Survey (MANOS) observed 308 near-Earth objects (NEOs) for light curves
(86 objects in Thirouin+ 2016, J/AJ/152/163 ; 142 here, and the
remainder will be reported in a future work).
MANOS employs a set of 1-4m telescopes for photometric purposes: the
1.3m Small and Moderate Aperture Research Telescope System (SMARTS)
telescope at CTIO, the 2.1m and the 4m Mayall telescopes at Kitt Peak
Observatory, the 4.1m Southern Astrophysical Research (SOAR)
telescope, and the Lowell's Observatory 4.3m Discovery Channel
Telescope (DCT).
Only 9 MANOS NEOs have a long rotation, a ΔvNHATS≤12km/s; and
have been observed for spectroscopy (Table 2, and Table 2 in Thirouin+
2016, J/AJ/152/163). We will present spectral results for these
objects in future publication(s).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 159 143 Observing log and results
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See also:
J/A+A/375/285 : Photometric observations of 9 Near-Earth Objects (Szabo+, 2001)
J/A+A/509/A94 : Lightcurves of 14 NEAs (Kwiatkowski+, 2010)
J/A+A/511/A49 : Lightcurves of 12 NEAs (Kwiatkowski+, 2010)
J/ApJ/743/156 : NEOWISE obs. of NEOs: preliminary results (Mainzer+, 2011)
J/ApJ/760/L12 : WISE/NEOWISE NEOs preliminary thermal fits (Mainzer+, 2012)
J/AJ/152/163 : Mission Accessible Near-Earth Objects Survey (Thirouin+, 2016)
J/AJ/154/168 : NEOWISE: thermal model fits for NEOs and MBAs (Masiero+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 I1 --- Set [1/6] Subset (1)
3- 14 A12 --- Name NEO designation
16- 16 A1 --- f_Name [bct] Source flag (2)
18- 27 A10 "D/M/Y" Date UT observation date
29- 33 A5 d Date2 Other days of observations if any
35- 37 I3 --- Nimg [9/398] Number of images
39- 49 A11 au rh Distance, sun-object or range during
observation
51- 63 A13 au Delta Distance, earth-object or range during
observation
65- 73 A9 deg alpha Phase angle or range during observation
75- 76 A2 --- Filt Filter (V, VR, r' or wh;
Thirouin+ 2016, J/AJ/152/163)
78- 81 A4 --- Tel Telescope (CTIO, DCT, KP2, KP4 or SOAR;
see the "Description" section above)
83- 92 A10 min DelT Duration(s) of observing block(s) (ΔT)
94- 98 A5 s texp Exposure time(s)
100 A1 --- l_Prot Limit flag on Prot
101-108 F8.6 h Prot [0.003/3]? Rotational period, hours
110-110 A1 --- l_Delm Limit flag on dm
111-114 F4.2 mag Delm [0.05/2.8]? Amplitude (Δm)
116-119 F4.2 mag e_Delm [0.02/0.07]? Uncertainty in Delm
121-130 F10.5 d JD Julian date of zero phase, JD-2450000
132-135 F4.1 mag Hmag [18.6/29.6] Absolute H magnitude
137-139 I3 m Diam [3/566] Estimated NEO diameter with albedo=20%
141-146 A6 --- Class Dynamical Class ("Amor", "Apollo" or "Aten")
148-152 F5.2 km/s DelV1 [3.8/11.6]? Velocity change, Shoemaker & Helin
(1978rpgp.rept...20S) (3)
154-159 F6.3 km/s DelV2 [4/12]? Velocity change, Near-Earth Object
Human Space Flight Accessible Targets Study (3)
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Note (1): Subset(s) as follows:
1 = Full lightcurve, symmetric;
2 = Full lightcurve, asymmetric;
3 = Full lightcurve, complex;
4 = Partial light curve;
5 = Flat lightcurve;
6 = Tumblers.
Note (2): Source flags as follows:
b = Two other lightcurves have been published for this object by
Warner (2015MPBu...42..115W 2015MPBu...42..115W) suggesting a rotational period of 31h
and by Kikwaya Eluo (2018ASSP...51.....G 2018ASSP...51.....G) with a periodicity of 1h.
For the purpose of our work, we use the MANOS result reported here;
c = Two lightcurves are reported for this object; Section 4.
t = Most suitable targets for a robotic/human mission;
flag added by CDS (from table 2).
Note (3): The velocity change for a Hohmann transfer orbit. See Section 6.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 12-Dec-2018