J/ApJS/227/20 Rotation periods of asteroids using iPTF (Chang+, 2016)
Large super-fast rotator hunting using the intermediate Palomar Transient
Factory.
Chang C.-K., Lin H.-W., Ip W.-H., Prince T.A., Kulkarni S.R., Levitan D.,
Laher R., Surace J.
<Astrophys. J. Suppl. Ser., 227, 20-20 (2016)>
=2016ApJS..227...20C 2016ApJS..227...20C (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets ; Surveys ; Photometry, RI
Keywords: minor planets, asteroids: general; surveys
Abstract:
In order to look for large super-fast rotators, in late 2014 and early
2015, five dedicated surveys covering ∼188deg2 in the ecliptic plane
have been carried out in the R-band, with ∼10min cadence using the
intermediate Palomar Transient Factory. Among 1029 reliable rotation
periods obtained from the surveys, we discovered 1 new large
super-fast rotator, (40511) 1999 RE88, and 18 other candidates.
(40511) 1999 RE88 is an S-type inner main-belt asteroid with a
diameter of D=1.9±0.3km, a rotation period of P=1.96±0.01hr, and a
light curve amplitude of Δm∼1.0mag. To maintain such fast
rotation, an internal cohesive strength of ∼780Pa is required.
Combining all known large super-fast rotators, their cohesive
strengths all fall in the range of 100-1000Pa of lunar regolith.
However, the number of large super-fast rotators seems to be far less
than the whole asteroid population. This might indicate a peculiar
asteroid group for them. Although the detection efficiency for a long
rotation period is greatly reduced due to our two-day observation time
span, the spin-rate distributions of this work show consistent results
with Chang+ (2015, J/ApJS/219/27), after considering the possible
observational bias in our surveys. It shows a number decrease with an
increase of spin rate for asteroids with a diameter of 3≤D≤15km, and
a number drop at a spin rate of f=5rev/day for asteroids with D≤3km.
Description:
To explore the transient and variable sky synoptically, the PTF/iPTF
employs the Palomar 48-inch Oschin Schmidt Telescope to create a field
of view of ∼7.26deg2 and a pixel scale of 1.01". The available
filters include the Mould-R band, with which most exposures were
taken, Gunn-g', and two different Hα-bands. The exposure time is
fixed at 60 seconds, which can reach a median limiting magnitude of
R∼21mag at the 5σ level.
In order to look for large super-fast rotators, we conducted five
asteroid rotation-period surveys during 2014 October 29-31 and
November 10-13, and 2015 January 18-19, February 20-21 and 25-26. Each
survey continuously scanned six consecutive PTF fields over the
ecliptic plane in the R-band, with a cadence of 10min. We ended up
with a total sky coverage of ∼188deg2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 133 1029 *Synodic rotation periods of PTF-U2s
table3.dat 133 352 Asteroids with partial phase coverage (PTF-Ps)
table4.dat 138 19 The super-fast rotator (40511) 1999 RE88 and
the 18 other candidates
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Note on table2.dat: "PTF-U2s" = The 1029 PTF-detected asteroids, with
reliable (i.e., U≥2) rotation periods. See section 4.
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See also:
II/313 : Palomar Transient Factory (PTF) photometric catalog 1.0 (Ofek+, 2012)
J/AJ/150/75 : Asteroid light curves from PTF survey (Waszczak+, 2015)
J/ApJS/219/27 : Surveys of asteroid rotation periods using iPTF (Chang+, 2015)
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)
http://www.minorplanetcenter.net/ : IAU minor planet center (MPC) home page
http://www.minorplanet.info/lightcurvedatabase.html : Asteroid lightcurve
database (LCDB)
Byte-by-byte Description of file: table[234].dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Object identifier (asteroid number or
MPC packed format)
8- 10 A3 --- f_ID Flag(s) on ID (1)
12 A1 --- --- [(]
13- 18 I6 --- Planet ? Asteroid number
19 A1 --- --- [)]
21- 35 A15 --- Name Name or preliminary designation if any
37- 40 F4.2 AU a [1.8/5.2] Semi-major axis
42- 45 F4.2 --- e [0/0.4] Eccentricity
47- 51 F5.2 deg i [0.07/30] Inclination
53- 57 F5.1 deg Omega Longitude of ascending node
59- 63 F5.1 deg omega Argument of periapsis
65- 68 F4.1 km Diam [0.1/60] Diameter
70 A1 --- f_Diam [w] w = WISE/NEOWISE diameter
72- 75 F4.2 AU Dist [1.7/5.1] Heliocentric distance
77- 80 F4.2 AU r [0.7/4.1] Geodesic distance
82- 86 F5.2 deg alpha [0.2/11] Phase angle
88- 92 F5.2 mag HRMag [9/22.1] Absolute HR band magnitude
94- 97 F4.2 mag e_HRMag [0.02/0.7] Uncertainty in HRMag
99 I1 --- Nn [1/9] Number of nights observed
101-103 I3 --- Ni [11/119] Number of images used
105-109 F5.2 mag PTFmag [13.8/25.4] PTF R band magnitude
111-114 F4.2 mag e_PTFmag [0/0.2] Uncertainty in PTFmag
116-120 F5.2 h Per [1/31] Derived rotation period
122-126 F5.2 h e_Per [0/79] Uncertainty in Per
128-131 F4.2 mag Amp [0.03/2.2] Lightcurve amplitude Δm (2)
133 I1 --- U [2/3] Rotation period quality code (3)
135-138 I4 --- k [40/4650]? Cohesion (only for table 4) (4)
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Note (1): Flag as follows:
* = Asteroid available in the Asteroid Light Curve Database (LCDB;
Warner+ 2009Icar..202..134W 2009Icar..202..134W;
http://www.minorplanet.info/lightcurvedatabase.html).
b = Lightcurves with large amplitudes and deep V-shape minima.
Note (2): For table 3: the amplitudes of the objects with partial lightcurve
coverage and lightcurves with a single minimum should be treated as
lower limits.
Note (3): Manually assigned to each folded lightcurve by visual inspection.
Code as follows:
3 = highly reliable;
2 = some ambiguity;
1 = possible, but may be wrong;
0 = no acceptable solution found.
Note (4): The cohesion k is calculated assuming a bulk density ρ=2g/cm3,
except for (40511) 1999 RE88. See also section 4.2.1.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Jan-2017