| 👁 Image Sinope photographed by the Haute-Provence Observatory on 14 August 1998 | |
| Discovery[1] | |
|---|---|
| Discovered by | Seth B. Nicholson |
| Discovery site | Lick Observatory |
| Discovery date | 21 July 1914 |
| Designations | |
Designation | Jupiter IX |
| Pronunciation | /səˈnoʊpiː/[2][3] |
Named after | Σινώπη Sinōpē |
| Adjectives | Sinopean[4] /saɪnəˈpiːən/[5] |
| Orbital characteristics[6] | |
| Epoch 2026-01-01 | |
| Observation arc | 103.87 yr (37,938 days) |
| Periapsis | 17.3 million km |
| Apoapsis | 30.0 million km |
| 23.6 million km | |
| Eccentricity | 0.269 |
| –741.8 days | |
| 1.94° | |
| 0° 27m 47.33s / day | |
| Inclination | 159.3° (to ecliptic) |
| 47.4° | |
| 79.2° | |
| Satellite of | Jupiter |
| Group | Pasiphae group |
| Physical characteristics | |
| 35.0±0.6 km[7] | |
| 13.16±0.10 h[8] | |
| Albedo | 0.042±0.006[7] |
Spectral type | D [7] |
| 18.3[9] | |
| 11.1[10] | |
Sinope /səˈnoʊpiː/ also known as Jupiter IX, is one of the outermost and larger irregular satellites of Jupiter.
Discovery and Naming
[edit]Sinope was discovered by Seth Barnes Nicholson at Lick Observatory in 1914. [1]
It is named after Sinope of Greek mythology. Sinope did not receive its present name until 1975;[11][12] before then, it was simply known as Jupiter IX. It was sometimes called "Hades"[13] between 1955 and 1975.
Orbit
[edit]
Sinope orbits Jupiter at an average distance of 23.6 million km in 742 days, at an inclination of about 159° to the ecliptic, in a retrograde direction and with an eccentricity of 0.269.[6] Its orbit is continuously changing due to solar and planetary perturbations.
Sinope belongs to the Pasiphae group, a group of retrograde moons jupiters with semi-major axes spread over 22–25 million km, inclinations between 141° and 158°, and higher eccentricities between 0.22 and 0.44.
Sinope is also known to be in a secular resonance with Jupiter, similar to Pasiphae. However, Sinope can drop out of this resonance and has periods of both resonant and non-resonant behaviour in time scales of 107 years.[14]
Physical characteristics
[edit]
From measurements of its thermal emission, Sinope has an estimated diameter of about 35 kilometers and a visible light albedo of 4.2%.[7]
Sinope is pale red in color (colour indices B−V=0.84, R−V=0.46),[15] and it falls under the light red color-class, comparable to P-type asteroids and D-type asteroids. This sets it apart from Pasiphae, which is closer to C-type asteroids. Sinope's infrared spectrum is similar to those of D-type asteroids but different from that of Pasiphae.[16] These dissimilarities of the physical parameters suggest a different origin from the core members of the group.
Furthermore, a measured low beam value of 0.82 ± 0.02 indicates that Sinope has considerable surface roughness.[7]
The rotation period is approximately 13 hours and 9,6 minutes with a peak amplitude of about ~0.2 magnitudes.[8]
Origin
[edit]Sinope probably did not form near Jupiter but was captured by Jupiter later. Like the other members of the Pasiphae group, which have similar orbits, Sinope is probably the remnant of a broken, captured heliocentric asteroid.
However, given its mean inclination and different colour, Sinope could be also an independent object, captured independently, unrelated to the collision and break-up at the origin of the group.[15]
Aoede, a small irregular moon of Jupiter, has a similar orbit to Sinope and could be a remnant of the latter.[7]
See also
[edit]References
[edit]- ^ a b Nicholson, S. B. (1914). "Discovery of the Ninth Satellite of Jupiter". Publications of the Astronomical Society of the Pacific. 26 (1): 197–198. Bibcode:1914PASP...26..197N. doi:10.1086/122336. PMC 1090718. PMID 16586574.
- ^ "Sinope". Dictionary.com Unabridged (Online). n.d.
- ^ Noah Webster (1884) A Practical Dictionary of the English Language
- ^ Sergey Vnukov (2010) "Sinopean Amphorae of the Roman Period", Ancient Civilizations from Scythia to Siberia 16
- ^ Hector Stuart (1876) Ben Nebo, and Other Poems, p. 22
- ^ a b Horizons output. "Jovian Osculating Orbital Elements for Sinope (509)". Retrieved 18 December 2025.
- ^ a b c d e f Grav, T.; Bauer, J. M.; Mainzer, A. K.; Masiero, J. R.; Nugent, C. R.; Cutri, R. M.; et al. (August 2015). "NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal. 809 (1): 9. arXiv:1505.07820. Bibcode:2015ApJ...809....3G. doi:10.1088/0004-637X/809/1/3. S2CID 5834661. 3.
- ^ a b Luu, Jane (September 1991). "CCD photometry and spectroscopy of the outer Jovian satellites". Astronomical Journal. 102: 1213–1225. Bibcode:1991AJ....102.1213L. doi:10.1086/115949. ISSN 0004-6256.
- ^ Sheppard, Scott. "Scott S. Sheppard - Jupiter Moons". Department of Terrestrial Magnetism. Carnegie Institution for Science. Retrieved 26 November 2020.
- ^ "M.P.C. 111777" (PDF). Minor Planet Circular. Minor Planet Center. 25 September 2018.
- ^ Nicholson, S. B. (April 1939). "The Satellites of Jupiter". Publications of the Astronomical Society of the Pacific. 51 (300): 85–94. Bibcode:1939PASP...51...85N. doi:10.1086/125010. (in which he declines to name the recently discovered satellites (pp. 93–94))
- ^ IAUC 2846: Satellites of Jupiter 1974 October (naming the moon)
- ^ Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-13-478107-4.
- ^ Nesvorný, D.; Beaugé, C. & Dones, L. (2004). "Collisional Origin of Families of Irregular Satellites". The Astronomical Journal. 127 (3): 1768–1783. Bibcode:2004AJ....127.1768N. doi:10.1086/382099.
- ^ a b Grav, T.; Holman, M. J.; Gladman, B. J.; and Aksnes, K.; Photometric Survey of the Irregular Satellites, Icarus, Vol. 166 (2003), pp. 33-45
- ^ Grav, T.; Holman, M. J. (2004). "Near-Infrared Photometry of the Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal. 605 (2): L141–L144. arXiv:astro-ph/0312571. Bibcode:2004ApJ...605L.141G. doi:10.1086/420881. S2CID 15665146.
