J/AJ/133/26 Solar phase curves of distant icy bodies (Rabinowitz+, 2007)
The diverse solar phase curves of distant icy bodies.
I. Photometric observations of 18 trans-neptunian objects, 7 Centaurs,
and Nereid.
Rabinowitz D.L., Schaefer B.E., Tourtellotte S.W.
<Astron. J., 133, 26-43 (2007)>
=2007AJ....133...26R 2007AJ....133...26R
ADC_Keywords: Minor planets ; Photometry
Keywords: Kuiper Belt - Oort Cloud -
planets and satellites: individual (Nereid) - scattering
Abstract:
We have measured the solar phase curves in B, V, and I for 18
trans-Neptunian objects (TNOs), 7 Centaurs, and Nereid and determined
the rotation curves for 10 of these targets. For each body we have
made ∼100 observations uniformly spread over the entire visible range.
We find that all the targets except Nereid have linear phase curves at
small phase angles (0.1°-2.0°) with widely varying phase
coefficients (0.0-0.4mag/deg). At phase angles of 2°-3°, the
Centaurs (54598) Bienor and (32532) Thereus have phase curves that
flatten. The recently discovered Pluto-scale bodies (2005 FY9, 2003
EL61, and 2003 UB313 now known as 136199 Eris), like Pluto, have
neutral colors compared to most TNOs and small phase coefficients
(∼0.1mag/deg). Together, these two properties are a likely indication
of large TNOs with high-albedo, freshly coated icy surfaces. We find
several bodies with significantly wavelength-dependent phase curves.
The TNOs (50000) Quaoar, (120348) 2004 TY364, and (47932) 2000 GN171
have unusually high I-band phase coefficients and much lower
coefficients in the B and V bands. Their phase coefficients increase
in proportion to wavelength by 0.5-0.8mag/deg/um. The phase curves for
TNOs with small B-band phase coefficients (<0.1mag/deg) have a similar
but weaker wavelength dependence. Coherent backscatter is the likely
cause for the wavelength dependence for all these bodies. We see no
such dependence for the Centaurs, which have visual albedos of ∼0.05.
Description:
The observations we report here were made by on-site operators at
Cerro Tololo using the 1.3m telescope of the Small and Moderate
Aperture Research Telescope System (SMARTS) consortium.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 94 26 Target properties
table3.dat 89 3357 Measured magnitudes for Trans-Neptunian objects
(TNOs), Centaurs, and Nereid
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See also:
J/A+A/468/L13 : Photometry of the trans-Neptunian object 2005FY9 (Ortiz+ 2007)
J/A+AS/136/445 : CCD observations of Nereid (Veiga+, 1999)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- T [TCN] Object type (T=TNOs, N=Nereid, C=Centaurs)
3 A1 --- --- [(]
4- 9 I6 --- Planet ? Target planet number
10 A1 --- --- [)]
12- 21 A10 --- Name Target name (1)
24- 27 F4.1 AU q ? Perihelion (2)
30- 34 F5.1 AU Q ? Aphelion (2)
36- 39 F4.1 mag H ? Absolute magnitude H parameter (2)
41- 44 F4.1 deg i ? Inclination (2)
46- 51 F6.3 --- e ? Eccentricity (2)
53- 57 F5.1 AU a ? Semi-major axis (2)
59- 62 F4.2 mag Amp ?=- Amplitude of the rotational light curve
64- 67 F4.2 mag e_Amp ?=- rms uncertainty on Amplitude
69- 76 F8.6 d Per ?=- Period of the rotational light curve (3)
77 A1 --- r_Per [ehij] Period reference (4)
79- 80 I2 s e_Per ?=- Period Error
83- 87 F5.3 --- pv ?=- Visual albedo
89- 93 F5.3 --- e_pv ?=- rms uncertainty on pv
94 A1 --- r_pv [abcdg] Reference for visual albedo (4)
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Note (1): Nereid was added at the end of the table to have all observed objects.
Note (2): Orbital elements and H-values are from the Minor Planet Center
(http://www.cfa.harvard.edu/iau/mpc.html).
Nereid is given Neptune's orbital elements.
Note (3): Where referenced, periods are the values determined by others
[2002 UX25 and (8405) Asbolus] or else they are one of several
multiple solutions from our own analysis that matches values
independently determined by others. Unreferenced periods were
determined solely from the data we report in this paper or in
Rabinowitz et al. (2006ApJ...639.1238R 2006ApJ...639.1238R).
Note (4): References as follows:
a = Brown et al. (2006ApJ...643L..61B 2006ApJ...643L..61B)
b = Rabinowitz et al. (2006ApJ...639.1238R 2006ApJ...639.1238R)
c = Brown & Trujillo (2004AJ....127.2413B 2004AJ....127.2413B)
d = Stansberry et al. (2005, BAAS, 37, 737)
e = Rousselot et al. (2005, Icarus, 176, 478)
f = Brown et al. (1998ApJ...508L.175B 1998ApJ...508L.175B)
g = Stansberry et al. (2006ApJ...643..556S 2006ApJ...643..556S)
h = Sheppard & Jewitt (2002AJ....124.1757S 2002AJ....124.1757S)
i = Mueller et al. (2004, Icarus, 171, 506)
j = Kern et al. (2000ApJ...542L.155K 2000ApJ...542L.155K)
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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 A1 --- --- [(]
2- 7 I6 --- Planet ? Target planet number
8 A1 --- --- [)]
10- 19 A10 --- Name Target name
21- 33 F13.5 d JD Julian Date of mid-exposure time
35- 40 F6.3 mag mag Apparent magnitude in Filt
42- 46 F5.3 mag e_mag Uncertainty in apparent mag
48- 60 F13.5 d JDcorr Light-travel time corrected Julian Date (1)
62- 67 F6.3 mag magr Reduced magnitude in Filt (2)
69- 73 F5.3 deg alpha Phase angle
75- 80 F6.3 AU r Heliocentric distance
82- 87 F6.3 AU d Geocentric distance
89 A1 --- Filt [BVRI] Filter used in the observation
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Note (1): The correction for light-travel time, subtracted from the UT
date, is (d-d0)/c where d0 is the geocentric distance at the time of
the earliest observation for each target and c is the speed of light.
Note (2): The reduced magnitude is the apparent magnitude minus 5log(rd)
with r and d expressed in AU. Extrapolated to alpha=0°, the reduced
magnitude is the absolute magnitude in the respective filter band.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 15-Nov-2008