J/AJ/152/163 Mission Accessible Near-Earth Objects Survey (Thirouin+, 2016)
The Mission Accessible Near-Earth Objects Survey (MANOS): first photometric
results.
Thirouin A., Moskovitz N., Binzel R.P., Christensen E., Demeo F.E.,
Person M.J., Polishook D., Thomas C.A., Trilling D., Willman M., Hinkle M.,
Burt B., Avner D., Aceituno F.J.
<Astron. J., 152, 163-163 (2016)>
=2016AJ....152..163T 2016AJ....152..163T (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets
Keywords: minor planets, asteroids: general
Abstract:
The Mission Accessible Near-Earth Objects Survey aims to physically
characterize sub-km near-Earth objects (NEOs). We report the first
photometric results from the survey that began in 2013 August.
Photometric observations were performed using 1-4m class telescopes
around the world. We present rotational periods and light curve
amplitudes for 86 sub-km NEOs, though in some cases only lower limits
are provided. Our main goal is to obtain light curves for small NEOs
(typically, sub-km objects) and estimate their rotational periods,
light curve amplitudes, and shapes. These properties are used for a
statistical study to constrain overall properties of the NEO
population. A weak correlation seems to indicate that smaller objects
are more spherical than larger ones. We also report seven NEOs that
are fully characterized (light curve and visible spectra) as the most
suitable candidates for a future human or robotic mission. Viable
mission targets are objects fully characterized, with
ΔvNHATS≤12km/s, and a rotational period P>1hr. Assuming a
similar rate of object characterization as reported in this paper,
approximately 1230 NEOs need to be characterized in order to find 100
viable mission targets.
Description:
The data were obtained with the 4.3m Lowell Discovery Channel
Telescope (DCT), the 4.1m Southern Astrophysical Research (SOAR)
telescope, the 4m Nicholas U. Mayall Telescope, the 2.1m at Kitt Peak
Observatory, the 1.8m Perkins telescope, the 1.5m Sierra Nevada
Observatory (OSN), and the 1.3m SMARTS telescope between 2013 August
and 2015 October.
The DCT is forty miles southeast of Flagstaff at the Happy Jack site
(Arizona, USA). Images were obtained using the Large Monolithic Imager
(LMI), which is a 6144*6160 CCD. The total field of view is 12.5*12.5
with a plate scale of 0.12''/pixel (unbinned). Images were obtained
using the 3*3 or 2*2 binning modes. Observations were carried out in
situ.
The SOAR telescope is located on Cerro Pachon, Chile. Images were
obtained using the Goodman High Throughput Spectrograph (Goodman-HTS)
instrument in its imaging mode. The instrument consists of a 4096*4096
Fairchild CCD, with a 7.2' diameter field of view (circular field of
view) and a plate scale of 0.15''/pixel. Images were obtained using
the 2*2 binning mode. Observations were conducted remotely.
The Mayall telescope is a 4m telescope located at the Kitt Peak
National Observatory (Tucson, Arizona, USA). The National Optical
Astronomy Observatory (NOAO) CCD Mosaic-1.1 is a wide field imager
composed of an array of eight CCD chips. The field of view is 36'*36',
and the plate scale is 0.26''/pixel. Observations were performed
remotely.
The 2.1m at Kitt Peak Observatory was operated with the STA3 2k*4k
CCD, which has a plate scale of 0.305''/pixel and a field of view of
10.2'*6.6'. The instrument was binned 2*2 and the observations were
conducted in situ.
The Perkins 72'' telescope is located at the Anderson Mesa station at
Lowell Observatory (Flagstaff, Arizona, USA). We used the Perkins
ReImaging SysteM (PRISM) instrument, a 2*2k Fairchild CCD. The PRISM
plate scale is 0.39''/pixel for a field of view of 13'*13'.
Observations were performed in situ.
The 1.5m telescope located at the OSN at Loma de Dilar in the National
Park of Sierra Nevada (Granada, Spain) was operated in situ.
Observations were carried out with a 2k*2k CCD, with a total field of
view of 7.8'*7.8'. We used 2*2 binning mode, resulting in an effective
plate scale of 0.46''/pixel.
The 1.3m SMARTS telescope is located at the Cerro Tololo
Inter-American Observatory (Coquimbo region, Chile). This telescope is
equipped with a camera called ANDICAM (A Novel Dual Imaging CAMera).
ANDICAM is a Fairchild 2048*2048 CCD. The pixel scale is
0.371''/pixel, and the field of view is 6'*6'. Observations were
carried out in queue mode.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 172 89 *Summary of observations
table2.dat 54 33 *All 33 MANOS targets with a ΔvNHATS
lower than 12km/s
--------------------------------------------------------------------------------
Note on table1.dat,table2.dat: The Mission Accessible Near-Earth Objects Survey
(MANOS) began in 2013 August as a multi-year survey program (2013B-2016B)
awarded by the National Optical Astronomy Observatory (NOAO), and funded
through NASA NEOO (Near-Earth Object Observations) office. MANOS is a physical
characterization survey of NEOs providing physical data for several hundred
mission accessible NEOs across visible and near-infrared wavelengths.
--------------------------------------------------------------------------------
See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
J/A+A/511/A49 : Lightcurves of 12 NEAs (Kwiatkowski+, 2010)
J/A+A/509/A94 : Lightcurves of 14 NEAs (Kwiatkowski+, 2010)
http://www.minorplanetcenter.net/ : Minor Planet Center (MPC)
https://manosobs.wordpress.com/ : MANOS website
https://pds.nasa.gov/ : Planetary Data System (PDS)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- LCType Type of light curve (Full, Partial, or Flat) (1)
9- 20 A12 --- Full Type of full light curve (Symmetric, Asymmetric,
Complex, or Partially constrained) (2)
22- 31 A10 --- Name Object name
33 A1 --- f_Name [bc] Flag on Name (b=see future work,
or c=contact binary) (3)
35- 44 A10 "Y:M:D" Date1 UT date of observation
46- 55 A10 "Y:M:D" Date2 Second UT date of observation for 2013 BO76
57- 66 A10 "Y:M:D" Date3 Third UT date of observation for 2013 BO76
68- 70 I3 --- Nimg [40/432]? Number of images (Nim)
72- 77 F6.4 AU Rh0 [0.99/2.16]? Heliocentric distance (or starting
heliocentric distance range) (rh)
78 A1 --- --- [-]
79- 83 F5.3 AU Rh1 [1/1.4]? Ending heliocentric distance range
(rh)
85- 90 F6.4 AU Delta0 [0.007/1.184]? Geocentric distance (or starting
geocentric distance range) (Δ)
91 A1 --- --- [-]
92- 96 F5.3 AU Delta1 [0.013/0.74]? Ending geocentric distance range
(Δ)
98-102 F5.2 deg alpha0 [0.84/96.1]? Phase angle (or starting phase
angle range (α)
103 A1 --- --- [-]
104-108 F5.2 deg alpha1 [0.1/96.25]? Ending phase angle (α)
110-112 A3 --- Flt Photometric filter (either Cle, R, V, VR, r',
or wh)
114-120 A7 --- Tel Telescope (CTIO, DCT, KP2, KP4, OSN, Perkins,
or SOAR) (4)
122 A1 --- l_Per [>] Lower limit flag on Per
123-129 F7.5 h Per [0.004/5.1]? Preferred rotational period
130 A1 --- l_Dmag [>] Lower limit flag on Dmag
131-134 F4.2 mag Dmag [0.01/1.65]? Peak-to-peak light curve amplitude
(Δm) (5)
136-139 F4.2 mag e_Dmag [0.01/0.2]? Uncertainty in Dmag
141-150 F10.5 d phi0 [6507.4/7293.9]? Julian date (φ0)
corresponding to phase zero (6)
152-155 F4.1 mag HMag [18.1/29.6]? Absolute magnitude (G1)
157-159 I3 m Diam [3/712]? Crude estimate of the object diameter
assuming an albedo of 0.20
161-166 A6 --- Class Dynamical class (Amor, Apollo, or Aten groups)
168-172 F5.2 km/s delta-v [3.9/12.9]? Low Earth Orbit-Near Earth Object
(LEO-NEO) delta-v computed using the
Shoemaker & Helin 1978rpgp.rept...20S
formalism (ΔvSH) (G2)
--------------------------------------------------------------------------------
Note (1): Our data set is classified into three categories defined as follows:
Full = Object with a full light curve;
Partial = Object with only a partial light curve. See Section 4.1.3 for
details;
Flat = Object with a flat light curve (i.e., no significant variability
during our observing). See Section 4.1.3 for details.
Note (2): The types of full light curves are defined as follows:
Symmetric = A symmetric light curve is one where both peaks reach the
same relative magnitude (see Section 4.1.1 for details);
Asymmetric = Most of the reported light curves are asymmetric with peaks
that are not of the same amplitude. In our sample, the
typical asymmetry is <0.15mag;
Complex = Ten MANOS targets display complex light curves that require
higher order harmonics (i.e., more than two harmonics) in
the fit. Such curves can only be explained by complex shape
and/or strong albedo variations (see Section 4.1.2 for
details);
Part. const. = Partially constrained.
Note (3): Flag on name defined as follows:
b = Object whose study will be presented in details in future work.
Observing circumstancies are not reported here;
c = Contact binary (Benner et al. 2014DPS....4640901B).
Note (4): Facility details are defined as follows:
Perkins = The 1.8m Perkins telescope;
CTIO = The 1.3m Small and Moderate Aperture Research Telescope System
(SMARTS) telescope, located at the Cerro Tololo Inter-American
Observatory (CTIO; Coquimbo region, Chile);
SOAR = The 4.1m Southern Astrophysical Research (SOAR) telescope;
DCT = The 4.3m Lowell Discovery Channel Telescope (DCT). The DCT is
forty miles southeast of Flagstaff at the Happy Jack site
(Arizona, USA);
KP2 = The 2.1m at Kitt Peak Observatory;
KP4 = The 4m Nicholas U. Mayall Telescope (Kitt Peak Observatory);
OSN = The 1.5m Sierra Nevada Observatory (OSN).
Note (5): Without phase angle correction.
Note (6): The Julian date is not light time corrected.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Object name
12 A1 --- f_Name [b] Flag on Name (b=best candidate for
future mission) (1)
14- 17 F4.1 mag HMag [20.7/29.6] Absolute H-band magnitude (G1)
19- 21 I3 m Diam [3/215] Crude estimate of the object diameter
assuming an albedo of 0.20
23 A1 --- l_Per [>] Lower limit flag on Per
24- 30 F7.5 h Per [0.004/4.9]? Preferred rotational period
32- 34 A3 --- Vis Visual spectrum? (yes or no)
36- 39 F4.2 km/s delta-v1 [3.9/8] Low Earth Orbit-Near Earth Object
(LEO-NEO) delta-v computed using the
Shoemaker & Helin 1978rpgp.rept...20S
formalism (ΔvSH) (G2)
41- 46 F6.3 km/s delta-v2 [4.2/12] Parameter Δv according the
Near-Earth Object Human Space Flight
Accessible Targets Study (NHATS)
(ΔvNHATS) (2)
48- 54 A7 --- Next Next optical window (3)
--------------------------------------------------------------------------------
Note (1): The best candidates are objects with a long rotational period, a
ΔvNHATS lower than 12km/s, and are objects fully characterized
(light curves and spectra).
Note (2): The Shoemaker & Helin 1978rpgp.rept...20S formalism is only a first
approximation to estimate if an object is truly spacecraft accessible. In
fact, full orbital integrations are needed to calculate accurate Δv.
The Near-Earth Object Human Space Flight Accessible Targets Study (NHATS)
performs more accurate ΔvNHATS calculations that take into account
specific launch windows, and the duration of the mission. For more details,
see http://neo.jpl.nasa.gov/nhats/
Note (3): The next opportunity to observe the best candidates for future
missions (dates from NHATS webpage (http://neo.jpl.nasa.gov/nhats/). We
also included the next window for objects with P>1hr, but without visible
spectrum, as well as object with a potentially slow rotation or unknown
rotation.
--------------------------------------------------------------------------------
Global Notes:
Note (G1): From the Minor Planet Center (MPC;
http://www.minorplanetcenter.net/iau/lists/MPLists.html) database (from
2016 February).
Note (G2): A key parameter for a mission to a Near-Earth Object (NEO) (and by
extension all missions) is the delta-v (Δv) required to reach the
orbit of the object. This parameter is the change in velocity needed to go
from Low Earth Orbit (LEO) to a NEO rendez-vous using a Hohman transfer
orbit. In first approximation, the LEO-NEO Δv values are computed
using the Shoemaker & Helin 1978rpgp.rept...20S formalism (ΔvSH).
On 2016 April, 14263 NEOs are known, and only 13 objects have a
ΔvSH<4km/s, 145 have a ΔvSH<4.5km/s, and 625 with a
ΔvSH≤5km/s
(http://echo.jpl.nasa.gov/~lance/delta_v/delta_v.rendezvous.html).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 02-Jun-2017