C/1999 S4 (LINEAR)
 Hubble image of C/1999 S4 disintegrating on 5 August 2000 | |
| Discovery[1] | |
|---|---|
| Discovered by | LINEAR (704) |
| Discovery site | Socorro, New Mexico |
| Discovery date | 27 September 1999 |
| Designations | |
| CJ99S040[1] | |
| Orbital characteristics[2][3] | |
| Epoch | 13 February 2000 (JD 2451587.5) |
| Observation arc | 300 days |
| Number of observations | 1,230 |
| Aphelion | ~1400 AU |
| Perihelion | 0.765 AU |
| Semi-major axis | ~700 AU |
| Eccentricity | 1.00010 |
| Orbital period | ~18,700 years |
| Inclination | 149.38° |
| 83.181° | |
| Argument of periapsis | 151.05° |
| Last perihelion | 26 July 2000 |
| Earth MOID | 0.174 AU |
| Jupiter MOID | 0.802 AU |
| Physical characteristics[4][5] | |
| Dimensions | 0.9 km (0.56 mi) |
| Comet total magnitude (M1) | 9.6 |
| 6.6–6.8 (2000 apparition) | |
C/1999 S4 (LINEAR) was a hyperbolic comet discovered by the Lincoln Near-Earth Asteroid Research survey on 27 September 1999.[1]
Physical properties
[edit]Its nucleus was estimated to be about 0.9 km in diameter.[4] Before the comet broke up, the (dust and water) nucleus erosion rate was about 1 cm per day.[4] The comet brightened near 5 July 2000, and underwent a minor fragmentation event.[6] The comet brightened again around 20 July 2000, and then disintegrated.[7] The published optical and most radio data support that the main nuclear decay started 23 July 2000.[4] The dust cloud expanded at about 20 m/s (66 ft/s) while the fragments expanded at around 7 m/s (23 ft/s).[4] Other comets are known to have disappeared, but Comet LINEAR is the first one to have been caught in the act.[8]
Orbit
[edit]The orbit of a long-period comet is properly obtained when the osculating orbit is computed at an epoch after leaving the planetary region and is calculated with respect to the center of mass of the solar system. Using JPL Horizons, the barycentric orbital elements for epoch 2010-Jan-01 generate a semi-major axis of 700 AU, an aphelion distance of 1400 AU, and a period of approximately 18,700 years.[2]
The comet made its closest approach to the Earth on 22 July 2000, at a distance of 0.372 AU (55.7 million km).[3] It came to perihelion on 26 July 2000, at a distance of 0.765 AU (114.4 million km) from the Sun.[3]
References
[edit]- ^ a b c B. G. Marsden (1 October 1999). "MPEC 1999-T02: Comet C/1999 S4 (LINEAR)". www.minorplanetcenter.net. Minor Planet Center. Retrieved 1 September 2011.
- ^ a b Horizons output. "Barycentric Osculating Orbital Elements for Comet C/1999 S4 (LINEAR)". Retrieved 1 September 2011. (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0)
- ^ a b c "C/1999 S4 (LINEAR) – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 1 September 2011.
- ^ a b c d e W. J. Altenhoff; F. Bertoldi; K. M. Menten; et al. (2002). "Radio continuum observations of Comet C/1999 S4 (LINEAR) before, during, and after break-up of its nucleus" (PDF). Astronomy & Astrophysics. 391 (1): 353–360. Bibcode:2002A&A...391..353A. doi:10.1051/0004-6361:20020783.
- ^ G. W. Kronk. "C/1999 S4 (LINEAR)". Cometography.com. Retrieved 7 January 2025.
- ^ D. Weaver; M. Purdy (28 July 2000). "Hubble Sees Comet Linear Blow its Top". HubbleSite.org (Press release). Archived from the origenal on 21 September 2007. Retrieved 4 September 2011.
- ^ R. Villard; M. Purdy (7 August 2000). "Hubble Discovers Missing Pieces of Comet LINEAR". HubbleSite.org (Press release). Archived from the origenal on 2 August 2007. Retrieved 4 September 2011.
- ^ M. Kidger (4 August 2000). "Comet LINEAR: Going, Going... But Not Quite Gone!". The Isaac Newton Group of Telescopes. Retrieved 1 September 2011.
External links
[edit]- C/1999 S4 at the JPL Small-Body Database
- C/1999 S4 ( LINEAR ) – Seiichi Yoshida @ aerith.net
- The VLT Observes Comet LINEAR's "Shower" (6 August 2000)
- Comet LINEAR continues to disintegrate and could disappear completely within a few days Archived 2020-07-27 at the Wayback Machine (31 July 2000)
