![]() Cardea photographed by the Canada–France–Hawaii Telescope in February 2007 | |
Discovery [1] | |
---|---|
Discovered by | LINEAR |
Discovery site | Lincoln Lab's ETS |
Discovery date | 13 April 2004 |
Designations | |
(164207) Cardea | |
Named after | Cardea |
2004 GU9 | |
NEO · Apollo | |
Orbital characteristics [2] | |
Epoch 13 January 2016 (JD 2457400.5) | |
Uncertainty parameter 0 | |
Observation arc | 5424 days (14.85 yr) |
Aphelion | 1.1376258581 AU (170.18640603 Gm) |
Perihelion | 0.86490477 AU (129.387912 Gm) |
1.001265315 AU (149.7871591 Gm) | |
Eccentricity | 0.1361882 |
1.00 yr (365.95 d) | |
154.915171° | |
0° 59m 1.464s / day | |
Inclination | 13.6490265° |
38.6405971° | |
280.55672±0.00007 ° | |
2456145.53817±0.00006 jd | |
280.28542° | |
Earth MOID | 0.000389702 AU (58,298.6 km) |
Physical characteristics | |
160–360 meters [3] | |
0.219 | |
21.1 [2] | |
164207 Cardea (provisional designation 2004 GU9) is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It is a quasi-satellite of Earth until around 2600. [4]
On 14 April 2004 (with less than a 1-day observation arc), the Sentry Risk Table showed 180 virtual impactors. [5] It was removed from the Sentry Risk Table 2 days later on 16 April 2004. [6] Cardea now has a well determined orbit with an observation arc of 12 years.
This asteroid was discovered on 13 April 2004 by the Lincoln Near-Earth Asteroid Research project near Socorro, New Mexico and given the provisional designation 2004 GU9. [1] Following the naming of 524522 Zoozve, a quasi-satellite of Venus, Radiolab and the International Astronomical Union held a public naming campaign for this quasi-satellite from June to September 2024. [7] [8] Seven finalist names were revealed in December 2024, with the names being Bakunawa, Cardea, Ehaema, Enkidu, Ótr, Tarriaksuk, and Tecciztecatl. [9] The winning name was Cardea, the Roman goddess of the hinge. The name was announced by the International Astronomical Union on 13 January 2025. [10]
(29075) 1950 DA is a risk-listed asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.3 kilometers in diameter. It once had the highest known probability of impacting Earth. In 2002, it had the highest Palermo rating with a value of 0.17 and a probability of 1 in 306 (0.33%) for a possible collision in 2880. Since that time, the estimated risk has been updated several times. In December 2015, the odds of an Earth impact were revised to 1 in 8,300 (0.012%) with a Palermo rating of −1.42. As of December 2024, it is listed on the Sentry Risk Table with the highest cumulative Palermo rating of −0.93. 1950 DA is not assigned a Torino scale rating, because the 2880 date is over 100 years in the future. As of 5 January 2025, the odds of an Earth impact are 1 in 2,600 (0.038%).
(35396) 1997 XF11 (provisional designation 1997 XF11) is a kilometer-sized asteroid, classified as a near-Earth object, Mars-crosser and potentially hazardous asteroid of the Apollo group.
2003 YN107 is a tiny asteroid, classified as a near-Earth object of the Aten group moving in a 1:1 mean-motion resonance with Earth. Because of that, it is in a co-orbital configuration relative to Earth.
A quasi-satellite is an object in a specific type of co-orbital configuration with a planet where the object stays close to that planet over many orbital periods.
524522 Zoozve (; provisional designation 2002 VE68) is a sub-kilometer sized asteroid and temporary quasi-satellite of Venus. Discovered in 2002, it was the first such object to be discovered around a major planet in the Solar System. It has nearly the same orbital period around the Sun that Venus does. In a frame of reference rotating with Venus, it appears to travel around it during one Venerean year, but it orbits the Sun, not Venus.
(612901) 2004 XP14 is a sub-kilometer asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group. It was first observed by the LINEAR project on 10 December 2004.
Claims of the existence of other moons of Earth—that is, of one or more natural satellites with relatively stable orbits of Earth, other than the Moon—have existed for some time. Several candidates have been proposed, but none have been confirmed. Since the 19th century, scientists have made genuine searches for more moons, but the possibility has also been the subject of a number of dubious non-scientific speculations as well as a number of likely hoaxes.
(277810) 2006 FV35, provisional designation 2006 FV35, is a sub-kilometer near-Earth asteroid in the dynamical Apollo asteroid group, discovered by Spacewatch at Kitt Peak National Observatory, Arizona, on 29 March 2006. It is a quasi-satellite of Earth. It is also notable for having a low delta-v requirement for rendezvous. Although its orbital period is almost exactly 1 year, the orbit of 2006 FV35 has a high eccentricity which causes it to cross the paths of both Venus and Mars.
343158 Marsyas (prov. designated2009 HC82) is an asteroid on a retrograde orbit, classified as a large near-Earth object of the Apollo group. It may be an extinct comet or damocloid asteroid. The asteroid was discovered on 29 April 2009, by astronomers with the Catalina Sky Survey at the Catalina Station near Tucson, Arizona, in the United States. Approximately 2 kilometers (1.2 miles) in diameter, it makes many close approaches to Earth, Venus, and Mars at a very high relative velocity. It was named after the satyr Marsyas from Greek mythology.
2012 EG5 is an Apollo near-Earth asteroid with an estimated diameter of 47 meters (154 ft). The asteroid was discovered on March 13, 2012. The asteroid came within 0.001539 AU of Earth during its closest approach on April 1, 2012, just over half the distance between Earth and the Moon's orbit. It was briefly listed on the Sentry Risk Table with a 1 in 2,778,000 chance of an impact in 2107. It was removed from the Sentry Risk Table on 1 April 2012.
2011 EO40 is an asteroid, classified as a near-Earth object and a potentially hazardous asteroid of the Apollo group. It is a possible candidate for the parent body of the Chelyabinsk superbolide.
2009 RR micro-asteroid, classified as near-Earth object of the Apollo group. It was discovered on 11 September 2009 by the Catalina Sky Survey at an apparent magnitude of 19.5 using a 0.68-meter (27 in) Schmidt–Cassegrain telescope. 2009 RR was the only asteroid discovered before 2014 that was predicted to potentially pass inside the orbit of the Moon during 2014. The asteroid has an estimated diameter of 26 meters (85 ft) and is listed on the Sentry Risk Table. It is not large enough to qualify as a potentially hazardous object.
2014 OL339 (also written 2014 OL339) is an Aten asteroid that is a temporary quasi-satellite of Earth, the fourth known Earth quasi-satellite.
2013 LX28, is an asteroid, classified as near-Earth object of the Apollo group that is a temporary quasi-satellite of the Earth, the third known Earth quasi-satellite.
2009 BD is a very small asteroid, approximately 10 meters in diameter, which is classified as near-Earth object of the Apollo group and as an Earth co-orbital asteroid.
2012 TV is a near-Earth Apollo asteroid with an estimated diameter of 30 metres (98 ft). Its closest approach to the Earth was on October 7, 2012, with a distance of 0.0017 astronomical units. It also approached the Moon an hour earlier with a distance of 0.0028 astronomical units. With a short observation arc of 1.8 days, the asteroid is listed on the Sentry Risk Table and has a 1:500,000 chance of impacting Earth on April 2, 2081.
2015 SO2 (astronomical naming convention: 2015 SO2) is an Aten asteroid that is a temporary horseshoe companion to the Earth, the ninth known Earth horseshoe librator. Prior to its most recent close encounter with our planet (2015 September 30) it was an Apollo asteroid.
469219 Kamoʻoalewa, provisionally designated 2016 HO3, is a very small elongated asteroid, fast rotator and near-Earth object of the Apollo group, approximately 40–100 meters (130–330 feet) in diameter. At present it is a quasi-satellite of Earth, and currently the second-smallest, closest, and most stable known such quasi-satellite (after 2023 FW13).
2020 PN1 is a sub-kilometer asteroid, classified as a near-Earth object of the Aten group, that is a temporary horseshoe companion to the Earth. There are dozens of known Earth horseshoe librators, some of which switch periodically between the quasi-satellite and the horseshoe co-orbital states.
2020 PP1 is a sub-kilometer asteroid, classified as a near-Earth object of the Apollo group, that is a temporary quasi-satellite of the Earth. There are over a dozen known Earth quasi-satellites, some of which switch periodically between the quasi-satellite and horseshoe co-orbital states.
Radiolab is partnering with the International Astronomical Union to launch a months-long global naming contest for one of Earth's quasi-moons (asteroid 164207).