66652 Borasisi, or as a binary (66652) Borasisi-Pabu,[7] is a binary classical Kuiper belt object. It was discovered in September 1999 by Chad Trujillo, Jane X. Luu and David C. Jewitt[4] and identified as a binary in 2003 by K. Noll and colleagues[4] using the Hubble Space Telescope.
Discovery | |
---|---|
Discovered by | A. Trujillo, J. Luu and D. Jewitt |
Discovery date | 8 September 1999 |
Designations | |
(66652) Borasisi | |
Pronunciation | /bɒrəˈsiːsi/ |
1999 RZ253 | |
trans-Neptunian object cubewano[1][2] SCATNEAR(?)[3] | |
Orbital characteristics[4] | |
Epoch 13 January 2016 (JD 2457400.5) | |
Uncertainty parameter 3 | |
Observation arc | 4790 days (13.11 yr) |
Aphelion | 47.291 AU (7.0746 Tm) |
Perihelion | 39.819 AU (5.9568 Tm) |
43.555 AU (6.5157 Tm) | |
Eccentricity | 0.085781 |
287.45 yr (104991 d) | |
60.025° | |
0.0034289°/day | |
Inclination | 0.56319° |
84.722° | |
194.98° | |
Known satellites | Pabu /ˈpɑːbuː/ (137 km in diameter?)[5] |
Physical characteristics | |
Mean diameter | 163+33 −66 km (combined) 126+25 −51 km (primary) 105+20 −42 km (secondary)[6] |
Mass | (3.433±0.027)×1018 kg[7] |
Mean density | 2.1+2.6 −1.2 g/cm3[6] |
6.4±1.0 h[6] | |
0.236+0.438 −0.77[6] | |
V−R= 0.646 ± 0.058[6] | |
6.121 ± 0.070,[6] 5.9[4] | |
In 2003 it was discovered that 66652 Borasisi is a binary with the components of comparable size (about 100–130 km) orbiting the barycentre on a moderately elliptical orbit.[6][8] The total system mass is about 3.4 × 1018 kg.[7]
The companion (66652) Borasisi I, named Pabu, orbits its primary in 46.2888 ± 0.0018 days on an orbit with semi-major axis of 4528 ± 12 km and eccentricity 0.4700 ± 0.0018. The orbit is inclined with respect to the observer by about 54° meaning that is about 35° from the pole-on position.[7]
The surface of both components of the Borasisi–Pabu system is very red.[6]
Borasisi is named after a fictional creation deity taken from the novel Cat's Cradle by Kurt Vonnegut.[9] In the book, Borasisi is the Sun and Pabu is the name of the Moon:[10]
Around 2005, Borasisi was considered as a target for the proposed New Horizons 2 after a Triton/Neptune flyby.[11]