Astronomy:4769 Castalia
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| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin Palomar Observatory (675) |
| Discovery date | 9 August 1989 |
| Designations | |
| (4769) Castalia | |
| Pronunciation | /kæˈsteɪliə/[2] |
| Named after | Castalia |
| 1989 PB | |
| Minor planet category | |
| Orbital characteristics[1] | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 9467 days (25.92 yr) |
| |{{{apsis}}}|helion}} | 1.5770 astronomical unit|AU (235.92 Gm) |
| |{{{apsis}}}|helion}} | 0.54957 AU (82.215 Gm) |
| 1.0633 AU (159.07 Gm) | |
| Eccentricity | 0.48313 (e) |
| Orbital period | 1.10 yr (400.46 d) |
| Mean anomaly | 327.23° |
| Mean motion | 0° 53m 56.256s / day |
| Inclination | 8.8863° |
| Longitude of ascending node | 325.59° |
| 121.35° | |
| Known satellites | 1 contact binary |
| Earth MOID | 0.0199 AU (7.7 LD)[1] |
| Physical characteristics | |
| Mean diameter |
|
| Rotation period | 4.095 h (0.1706 d)[1] |
| Absolute magnitude (H) | 16.9[1] |
4769 Castalia (/kəˈsteɪliə/; prov. designation: 1989 PB) is a near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.4 kilometers (0.87 miles) in diameter and was the first asteroid to be modeled by radar imaging. It was discovered on 9 August 1989, by American astronomer Eleanor Helin (Caltech) on photographic plates taken at Palomar Observatory in California. It is named after Castalia, a nymph in Greek mythology. It is also a Mars- and Venus-crosser asteroid.[1]
General information
On 25 August 1989 Castalia passed 0.0269378 astronomical unit|AU (4,029,840 km; 2,504,020 mi)[3] (within eleven lunar distances) of Earth, allowing it to be observed with radar from the Arecibo Observatory by Scott Hudson (Washington State University) and Steven J. Ostro (JPL). The data allowed Hudson et al. to produce a three-dimensional model of the object. During the 1989 passage Castalia peaked at an apparent magnitude of 12.[4]
Castalia has a peanut shape, suggesting two approximately 800-meter-diameter pieces held together by their weak mutual gravity. Since then radar observations of other asteroids have found other contact binaries.[5]
Castalia is a potentially hazardous asteroid (PHA) because its minimum orbit intersection distance (MOID) is less than 0.05 AU and its diameter is greater than 150 meters. The Earth-MOID is 0.0204 astronomical unit|AU (3,050,000 km; 1,900,000 mi).[1] Its orbit is well-determined for the next several hundred years.
| Date | JPL Horizons nominal geocentric distance (AU) |
uncertainty region (3-sigma) |
|---|---|---|
| 2023-Aug-22 09:21 | 0.11003 astronomical unit|AU (16.460 million km)[1] | ±6 km[6] |
See also
- List of notable asteroids
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 "JPL Small-Body Database Browser: 4769 Castalia (1989 PB)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Castalia.
- ↑ Castalia (3rd ed.), Oxford University Press, September 2005, http://oed.com/search?searchType=dictionary&q=Castalia (Subscription or UK public library membership required.)
- ↑ "JPL Close-Approach Data: 4769 Castalia (1989 PB)". https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Castalia;cad=1#cad.
- ↑ "(4769) Castalia Ephemerides for August 1989". NEODyS (Near Earth Objects – Dynamic Site). https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=4769&oc=500&y0=1989&m0=8&d0=1&h0=0&mi0=0&y1=1989&m1=9&d1=3&h1=0&mi1=0&ti=1.0&tiu=days.
- ↑ Lance A. M. Benner (2013-11-18). "Binary and Ternary near-Earth Asteroids detected by radar". NASA/JPL Asteroid Radar Research. http://echo.jpl.nasa.gov/~lance/binary.neas.html.
- ↑ "Horizons Batch for 2023-08-22 Close Approach". JPL Horizons. https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27Castalia%27&START_TIME=%272023-08-22%2009:21%27&STOP_TIME=%272023-08-23%27&STEP_SIZE=%271%20day%27&QUANTITIES=%2720,39%27. Retrieved 2022-10-26. RNG_3sigma = uncertainty range in km. (JPL#95/Soln.date: 2022-Jul-11 generates RNG_3sigma = 5.8 km)
External links
- Mike Nolan (1996-05-15). "Radar image of 4769 Castalia". Arecibo Observatory. http://www.naic.edu/~nolan/radar/Castalia.html.
- NASA Asteroid Radar Search – The 228 Radar-Detected Asteroids: Asteroid 4769 Castalia
- 4769 Castalia at NeoDyS-2, Near Earth Objects—Dynamic Site
- Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
- 4769 Castalia at ESA–space situational awareness
- 4769 Castalia at the JPL Small-Body Database
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