J/A+A/684/A50 (50000) Quaoar Kp and thermal infrared LCs (Kiss+, 2024)
The visible and thermal light curve of the large Kuiper belt object
(50000) Quaoar.
Kiss C., Mueller T.G., Marton G., Szakats R., Pal A., Molnar L.,
Vilenius E., Rengel M., Ortiz J.L., Fernandez-Valenzuela E.
<Astron. Astrophys. 684, A50 (2024)>
=2024A&A...684A..50K 2024A&A...684A..50K (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets ; Photometry, millimetric/submm ;
Optical
Keywords: Kuiper belt objects: individual: (50000) Quaoar
Abstract:
Recent stellar occultations have allowed accurate instantaneous size
and apparent shape determinations of the large Kuiper belt object
(50000) Quaoar and the detection of two rings with spatially variable
optical depths. In this paper we present new visible range light curve
data of Quaoar from the Kepler/K2 mission, and thermal light curves at
100 and 160um obtained with Herschel/PACS. The K2 data provide a
single-peaked period of 8.88h, very close to the previously determined
8.84h, and it favours an asymmetric double- peaked light curve with a
17.76h period. We clearly detected a thermal light curve with relative
amplitudes of ∼10% at 100 and at 160um. A detailed thermophysical
modelling of the system shows that the measurements can be best fit
with a triaxial ellipsoid shape, a volume-equivalent diameter of
1090km, and axis ratios of a/b=1.19 and b/c=1.16. This shape matches
the published occultation shape, as well as visual and thermal light
curve data. The radiometric size uncertainty remains relatively large
(±40km) as the ring and satellite contributions to the
system-integrated flux densities are unknown. In the less likely case
of negligible ring or satellite contributions, Quaoar would have a
size above1100 km and a thermal inertia ≤10J/m2/K1/s1/2. A large and
dark Weywot in combination with a possible ring contribution would
lead to a size below 1080km in combination with a thermal inertia
=>10J/m2/K1/s1/2, notably higher than that of smaller Kuiper belt
objects with similar albedo and colours. We find that Quaoar's density
is in the range 1.67-1.77g/cm3 , significantly lower than previous
estimates. This density value closely matches the relationship
observed between the size and density of the largest Kuiper belt
objects.
Description:
Visible (Kepler/K2) and thermal infrared (Herschel/PACS 100 and 160um)
light curves of the Kuiper belt object (50000) Quaoar.
objects:
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Planet Name H i e a
mag deg AU
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50000 Quaoar 2.51 7.990425 0.04154574 43.64120180
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 61 601 K2 light curve data of Quaoar
table3.dat 96 318 Herschel/PACS 100 and 160um light curve data
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See also:
J/A+A/664/L15 : CHEOPS Quaoar's stellar occultation (Morgado+, 2022)
J/A+A/673/L4 : The two rings of (50000) Quaoar (Pereira+, 2023)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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3- 15 F13.5 d Time Mean time of measurement (Julian date)
19- 24 F6.3 mag Kpmag Apparent Kepler magnitude
28- 32 F5.3 mag e_Kpmag Uncertainty in Kepler magnitude
36- 42 F7.4 au Rh Heliocentric distance
46- 52 F7.4 au delta Observer distance
56- 61 F6.4 deg alpha Phase angle
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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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3- 15 F13.5 d TimeS Start time of measurement (Julian date)
18- 30 F13.5 d TimeE End time of measurement (Julian date)
33- 42 I10 -- ObsId Herschel Space Observatory observation ID
45- 47 I3 um Filt [100 160] Filter identifier
(central wavelength, micrometer)
51- 53 I3 -- SR Starting repetition
56 I1 -- NM Number of repetitions merged
59- 63 F5.2 mJy FD In-band flux density
67- 70 F4.2 mJy e_FD In-band flux density uncertainty
73- 79 F7.4 au Rh Heliocentric distance
82- 88 F7.4 au delta Observer distance
91- 96 F6.4 deg alpha Phase angle
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Acknowledgements:
Csaba Kiss, kiss.csaba(at)csfk.org
(End) Csaba Kiss [Konkoly Obs., Hungary], Patricia Vannier [CDS] 27-Mar-2024