47171 Lempo
47171 Lempo, or as a binary (47171) Lempo–Hiisi (provisional designation 1999 TC36), is a trans-Neptunian object and trinary system from the Kuiper belt, located in the outermost regions of the Solar System. It was discovered on 1 October 1999, by American astronomers Eric Rubenstein and Louis-Gregory Strolger during an observing run at Kitt Peak National Observatory in Arizona, United States. Rubenstein was searching images taken by Strolger as part of their Nearby Galaxies Supernova Search project. It is classified as a plutino with a 2:3 mean-motion resonance with Neptune and is among the brighter TNOs. It reached perihelion in July 2015. This minor planet was named after Lempo from Finnish mythology.
Lempo–Hiisi and their outer companion Paha, imaged with the Hubble Space Telescope in 2001. Lempo and Hiisi are unresolved. | |
| Discovery | |
|---|---|
| Discovered by | Eric P. Rubenstein Louis-Gregory Strolger |
| Discovery site | Kitt Peak National Obs. |
| Discovery date | 1 October 1999 |
| Designations | |
MPC designation | (47171) Lempo |
| Pronunciation | /ˈlɛmpoʊ/ |
Named after | Lempo (Finnish mythology) |
Alternative designations | 1999 TC36 |
Minor planet category | TNO · plutino · distant · trinary |
| Orbital characteristics | |
| Epoch 17 December 2020 (JD 2459200.5) | |
| Uncertainty parameter 1 | |
| Observation arc | 46.58 yr (17,013 days) |
| Earliest precovery date | 18 June 1974 |
| Aphelion | 48.397 AU |
| Perihelion | 30.542 AU |
Semi-major axis | 39.470 AU |
| Eccentricity | 0.22618 |
Orbital period (sidereal) | 247.97 yr (90,572 days) |
Mean anomaly | 8.547° |
Mean motion | 0° 0m 14.309s / day |
| Inclination | 8.4233° |
Longitude of ascending node | 97.020° |
| 294.424° | |
| Known satellites | 2 |
| Physical characteristics | |
Mean diameter | 272+17 −19 km (primary) |
| Mass | (12.75±0.06)×1018 kg (overall system) (14.20±0.05)×1018 kg (without Paha) 6.71×1018 kg (primary) |
Mean density | 0.64+0.15 −0.11 g/cm3 (system) |
| 0.079+0.013 −0.011 (system) | |
| RR (very red) B–V=1.029±0.047 V−R=0.693±0.032 V−I=1.270±0.050 | |
| 19.9 | |
| 5.41±0.10 4.8 (assumed) | |
The trinary system's other two components, Paha /ˈpɑːhɑː/ and Hiisi /ˈhiːsi/, were discovered in 2001 and 2007, respectively, and later named after Lempo's two demon cohorts, Paha and Hiisi.