Quasi-satellite

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Diagram of generic quasi-satellite orbit Quasi-satellite diagram.svg
Diagram of generic quasi-satellite orbit

A quasi-satellite is an object in a specific type of co-orbital configuration (1:1 orbital resonance) with a planet (or dwarf planet) where the object stays close to that planet over many orbital periods.

Contents

A quasi-satellite's orbit around the Sun takes the same time as the planet's, but has a different eccentricity (usually greater), as shown in the diagram. When viewed from the perspective of the planet by an observer facing the Sun, the quasi-satellite will appear to travel in an oblong retrograde loop around the planet. (See Analemma § Of quasi-satellites).

In contrast to true satellites, quasi-satellite orbits lie outside the planet's Hill sphere, and are unstable. Over time they tend to evolve to other types of resonant motion, where they no longer remain in the planet's neighborhood, then possibly later move back to a quasi-satellite orbit, etc.

Other types of orbit in a 1:1 resonance with the planet include horseshoe orbits and tadpole orbits around the Lagrangian points, but objects in these orbits do not stay near the planet's longitude over many revolutions about the star. Objects in horseshoe orbits are known to sometimes periodically transfer to a relatively short-lived quasi-satellite orbit, [1] and are sometimes confused with them. An example of such an object is 2002 AA29 .

A quasi-satellite is similar to an object in a distant retrograde orbit, in a different context. The latter term is usually used for a space probe or artificial satellite in a retrograde orbit around a moon, and the period may be much shorter than that of the moon, whereas the term "quasi-satellite" usually refers to an object like an asteroid whose period is similar to that of the planet of which it is considered to be a quasi-satellite. But in both cases, the object (asteroid, space probe) viewed in a reference frame that rotates with the two main objects (once a year for Sun-Earth, once a month for Earth-Moon) appears to move retrograde compared to that rotation, thus lengthening its sidereal period. So a quasi-satellite (with low inclination) tends to stay in certain constellations rather than going through the whole zodiac. Quasi-satellites with high eccentricity can get quite far from their planet, more than an astronomical unit for quasi-satellites of Earth such as 2014 OL339 .

The word "geosynchronous" is sometimes used to describe quasi-satellites of the Earth, because their motion around the Sun is synchronized with Earth's. However, this usage is unconventional and confusing. Conventionally, geosynchronous satellites revolve in the prograde sense around the Earth, with orbital periods that are synchronized to the Earth's rotation.

Examples

Venus

Venus has one known quasi-satellite, 524522 Zoozve. This asteroid is also a Mercury- and Earth-crosser; it seems to have been a "companion" to Venus for approximately the last 7,000 years only, and is destined to be ejected from this orbital arrangement about 500 years from now. [2]

Earth

The oscillating path of asteroid 469219 Kamoʻoalewa viewed from Earth's perspective as it orbits around the Sun. The traced path of Kamoʻoalewa makes it appear as a constant companion of the Earth.

As of 2023, Earth had seven known quasi-satellites:

On the longer term, asteroids can transfer between quasi-satellite orbits and horseshoe orbits, which circulate around Lagrangian points L4 and L5. By 2016, orbital calculations showed that all five of Earth's then known quasi-satellites repeatedly transfer between horseshoe and quasi-satellite orbits. [8] 3753 Cruithne, [9] 2002 AA29 , [1] 2003 YN107 and 2015 SO2 [5] are minor planets in horseshoe orbits that might evolve into a quasi-satellite orbit. The time spent in the quasi-satellite phase differs from asteroid to asteroid. Quasi-satellite 2016 HO3 is predicted to be stable in this orbital state for several hundred years, in contrast to 2003 YN107 which was a quasi-satellite from 1996 to 2006 but then departed Earth's vicinity on a horseshoe orbit. [8] [10]

469219 Kamoʻoalewa (2016 HO3) is thought to be one of the most stable quasi-satellites found yet of Earth. It stays between 38 and 100  lunar distances from the Earth. [10]

Known and suspected companions of Earth
Name Eccentricity Diameter
(m)		DiscovererDate of DiscoveryTypeCurrent Type
Moon 0.0553474800 ?Prehistory Natural satellite Natural satellite
1913 Great Meteor Procession  ? ? ?1913-02-09Possible Temporary satellite Destroyed
3753 Cruithne 0.5155000 Duncan Waldron 1986-10-10 Quasi-satellite Horseshoe orbit
1991 VG 0.0535–12 Spacewatch 1991-11-06 Temporary satellite Apollo asteroid
(85770) 1998 UP1 0.345210–470 Lincoln Lab's ETS 1998-10-18 Horseshoe orbit Horseshoe orbit
54509 YORP 0.230124 Lincoln Lab's ETS 2000-08-03 Horseshoe orbit Horseshoe orbit
2001 GO2 0.16835–85 Lincoln Lab's ETS 2001-04-13Possible Horseshoe orbit Possible Horseshoe orbit
2002 AA29 0.01320–100 LINEAR 2002-01-09 Quasi-satellite Horseshoe orbit
2003 YN107 0.01410–30 LINEAR 2003-12-20 Quasi-satellite Horseshoe orbit
(164207) 2004 GU9 0.136160–360 LINEAR 2004-04-13 Quasi-satellite Quasi-satellite
(277810) 2006 FV35 0.377140–320 Spacewatch 2006-03-29 Quasi-satellite Quasi-satellite
2006 JY26 0.0836–13 Catalina Sky Survey 2006-05-06 Horseshoe orbit Horseshoe orbit
2006 RH120 0.0242–3 Catalina Sky Survey 2006-09-13 Temporary satellite Apollo asteroid
(419624) 2010 SO16 0.075357 WISE 2010-09-17 Horseshoe orbit Horseshoe orbit
(706765) 2010 TK7 0.191150–500 WISE 2010-10-01 Earth trojan Earth trojan
2013 BS45 0.08320–40 Spacewatch 2010-01-20 Horseshoe orbit Horseshoe orbit
2013 LX28 0.452130–300 Pan-STARRS 2013-06-12 Quasi-satellite temporary Quasi-satellite temporary
2014 OL339 0.46170–160 EURONEAR 2014-07-29 Quasi-satellite temporary Quasi-satellite temporary
2015 SO2 0.10850–110 Črni Vrh Observatory 2015-09-21 Quasi-satellite Horseshoe orbit temporary
2015 XX169 0.1849–22 Mount Lemmon Survey 2015-12-09 Horseshoe orbit temporary Horseshoe orbit temporary
2015 YA 0.2799–22 Catalina Sky Survey 2015-12-16 Horseshoe orbit temporary Horseshoe orbit temporary
2015 YQ1 0.4047–16 Mount Lemmon Survey 2015-12-19 Horseshoe orbit temporary Horseshoe orbit temporary
469219 Kamoʻoalewa 0.10440-100 Pan-STARRS 2016-04-27 Quasi-satellite stable Quasi-satellite stable
DN16082203  ? ? ?2016-08-22Possible Temporary satellite Destroyed
2020 CD3 0.0171–6 Mount Lemmon Survey 2020-02-15 Temporary satellite Temporary satellite
2020 PN1 0.12710–50 ATLAS-HKO 2020-08-12 Horseshoe orbit temporary Horseshoe orbit temporary
2020 PP1 0.07410–20 Pan-STARRS 2020-08-12 Quasi-satellite stable Quasi-satellite stable
(614689) 2020 XL5 0.3871100-1260 Pan-STARRS 2020-12-12 Earth trojan Earth trojan
2022 NX1 0.0255-15Moonbase South Observatory2020-07-02Temporary satellite Apollo asteroid
2023 FW13 0.17710-20 Pan-STARRS 2023-03-28 Quasi-satellite Quasi-satellite

Ceres

The dwarf-planet asteroid 1 Ceres is believed to have a quasi-satellite, the as-yet-unnamed (76146) 2000 EU16 .

Neptune

(309239) 2007 RW10 is a temporary quasi-satellite of Neptune. [11] The object has been a quasi-satellite of Neptune for about 12,500 years and it will remain in that dynamical state for another 12,500 years. [11]

Other planets

Based on simulations, it is believed that Uranus and Neptune could potentially hold quasi-satellites for up to the age of the Solar System (about 4.5 billion years), [12] but a quasi-satellite's orbit would remain stable for only 10 million years near Jupiter and 100,000 years near Saturn. Jupiter and Saturn are known to have quasi-satellites.[ clarification needed ] 2015 OL106 , a co-orbital to Jupiter, intermittently becomes a quasi satellite of the planet, and will next become one between 2380 and 2480.

Artificial quasi-satellites

In early 1989, the Soviet Phobos 2 spacecraft was injected into a quasi-satellite orbit around the Martian moon Phobos, with a mean orbital radius of about 100 kilometres (62 mi) from Phobos. [13] According to computations, it could have then stayed trapped in the vicinity of Phobos for many months. The spacecraft was lost due to a malfunction of the on-board control system.

Accidental quasi-satellites

Some objects are known to be accidental quasi-satellites, which means that they are not forced into the configuration by the gravitational influence of the body of which they are quasi-satellites. [14] The dwarf planets Ceres and Pluto are known to have accidental quasi-satellites. [14] In the case of Pluto, the known accidental quasi-satellite, 15810 Arawn, is, like Pluto, a plutino, and is forced into this configuration by the gravitational influence of Neptune. [14] This dynamical behavior is recurrent where Arawn becomes a quasi-satellite of Pluto every 2.4 Myr and remains in that configuration for nearly 350,000 years. [14] [15] [16]

See also

Related Research Articles

In astronomy, the plutinos are a dynamical group of trans-Neptunian objects that orbit in 2:3 mean-motion resonance with Neptune. This means that for every two orbits a plutino makes, Neptune orbits three times. The dwarf planet Pluto is the largest member as well as the namesake of this group. The next largest members are Orcus, (208996) 2003 AZ84, and Ixion. Plutinos are named after mythological creatures associated with the underworld.

<span class="mw-page-title-main">Solar System</span> The Sun and objects orbiting it

The Solar System is the gravitationally bound system of the Sun and the objects that orbit it. It was formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc. The Sun is a typical star that maintains a balanced equilibrium by the fusion of hydrogen into helium at its core, releasing this energy from its outer photosphere. Astronomers classify it as a G-type main-sequence star.

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.

<span class="mw-page-title-main">Horseshoe orbit</span> Type of co-orbital motion of a small orbiting body relative to a larger orbiting body

In celestial mechanics, a horseshoe orbit is a type of co-orbital motion of a small orbiting body relative to a larger orbiting body. The osculating (instantaneous) orbital period of the smaller body remains very near that of the larger body, and if its orbit is a little more eccentric than that of the larger body, during every period it appears to trace an ellipse around a point on the larger object's orbit. However, the loop is not closed but drifts forward or backward so that the point it circles will appear to move smoothly along the larger body's orbit over a long period of time. When the object approaches the larger body closely at either end of its trajectory, its apparent direction changes. Over an entire cycle the center traces the outline of a horseshoe, with the larger body between the 'horns'.

<span class="mw-page-title-main">524522 Zoozve</span> Temporary quasi-satellite of Venus

524522 Zoozve (provisional designation 2002 VE68) is a sub-kilometer sized asteroid and temporary quasi-moon 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.

<span class="mw-page-title-main">Trojan (celestial body)</span> Objects sharing the orbit of a larger one

In astronomy, a trojan is a small celestial body (mostly asteroids) that shares the orbit of a larger body, remaining in a stable orbit approximately 60° ahead of or behind the main body near one of its Lagrangian points L4 and L5. Trojans can share the orbits of planets or of large moons.

In astronomy, a co-orbital configuration is a configuration of two or more astronomical objects orbiting at the same, or very similar, distance from their primary; i.e., they are in a 1:1 mean-motion resonance..

<span class="mw-page-title-main">Retrograde and prograde motion</span> Relative directions of orbit or rotation

Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object. It may also describe other motions such as precession or nutation of an object's rotational axis. Prograde or direct motion is more normal motion in the same direction as the primary rotates. However, "retrograde" and "prograde" can also refer to an object other than the primary if so described. The direction of rotation is determined by an inertial frame of reference, such as distant fixed stars.

Paul Arnold Wiegert is a Canadian astronomer, discoverer of minor planets and professor at the University of Western Ontario.

2012 XE133 is an asteroid, classified as near-Earth object of the Aten group that is a temporary co-orbital of Venus.

2013 BS45 (also written 2013 BS45) is a horseshoe companion to the Earth like 3753 Cruithne. Like Cruithne, it does not orbit the Earth in the normal sense and at times it is on the other side of the Sun, yet it still periodically comes nearer to the Earth in sort of halo orbit before again drifting away. While not a traditional natural satellite, it does not quite have normal heliocentric orbit either and these are sometimes called quasi-satellties or horseshoe orbits.

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.

2015 SO2 (also written 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.

2015 YA is a sub-kilometer asteroid, classified as near-Earth object of the Aten group, that is a temporary horseshoe companion to the Earth. It is the 11th known Earth horseshoe librator. Prior to a close encounter with the Earth on 15 December 2015, 2015 YA was an Apollo asteroid.

<span class="mw-page-title-main">469219 Kamoʻoalewa</span> Near-Earth asteroid

469219 Kamoʻoalewa, provisionally designated 2016 HO3, is a very small 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). The asteroid was discovered by Pan-STARRS at Haleakala Observatory on 27 April 2016. It was named Kamoʻoalewa, a Hawaiian word that refers to an oscillating celestial object. The object's Earth-like orbit and its composition of lunar-like silicates may be a result of it being lunar ejecta.

A temporary satellite is an object which has been captured by the gravitational field of a planet and thus has become the planet's natural satellite, but, unlike irregular moons of the larger outer planets of the Solar System, will eventually either leave its orbit around the planet or collide with the planet. The only observed examples are 2006 RH120, a temporary satellite of Earth for twelve months from July 2006 to July 2007, and 2020 CD3, which was discovered in 2020. Some defunct space probes or rockets have also been observed on temporary satellite orbits.

2020 VT1 is a small asteroid, classified as a near-Earth object of the Amor group, that is a temporary horseshoe companion to Mars.

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.

References

  1. 1 2 Connors, Martin; Chodas, Paul; Mikkola, Seppo; Wiegert, Paul; Veillet, Christian; Innanen, Kimmo (2002). "Discovery of an asteroid and quasi-satellite in an Earth-like horseshoe orbit". Meteoritics & Planetary Science . 37 (10): 1435–1441. Bibcode:2002M&PS...37.1435C. doi: 10.1111/j.1945-5100.2002.tb01039.x .
  2. ↑ Mikkola, S.; Brasser, R.; Wiegert, P.; Innanen, K. (2004). "Asteroid 2002 VE68, a quasi-satellite of Venus". Monthly Notices of the Royal Astronomical Society . 351 (3): L63–L65. Bibcode:2004MNRAS.351L..63M. doi: 10.1111/j.1365-2966.2004.07994.x .
  3. ↑ Brasser, R.; et al. (September 2004). "Transient co-orbital asteroids". Icarus. 171 (1): 102–109. Bibcode:2004Icar..171..102B. doi:10.1016/j.icarus.2004.04.019.
  4. ↑ Wajer, Paweł (October 2010). "Dynamical evolution of Earth's quasi-satellites: 2004 GU9 and 2006 FV35" (PDF). Icarus. 209 (2): 488–493. Bibcode:2010Icar..209..488W. doi:10.1016/j.icarus.2010.05.012.
  5. 1 2 de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2016). "From horseshoe to quasi-satellite and back again: The curious dynamics of Earth co-orbital asteroid 2015 SO2". Astrophysics and Space Science. 361: 16. arXiv: 1511.08360 . Bibcode:2016Ap&SS.361...16D. doi:10.1007/s10509-015-2597-8. S2CID   189842725.
  6. ↑ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2014). "Asteroid 2014 OL339: Yet another Earth quasi-satellite". Monthly Notices of the Royal Astronomical Society . 445 (3): 2985–2994. arXiv: 1409.5588 . Bibcode:2014MNRAS.445.2961D. doi: 10.1093/mnras/stu1978 .
  7. ↑ Agle, D.C.; Brown, Dwayne; Cantillo, Laurie (15 June 2016). "Small asteroid is Earth's constant companion". NASA . Retrieved 15 June 2016.
  8. 1 2 3 de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2016). "Asteroid (469219) 2016 HO3, the smallest and closest Earth quasi-satellite". Monthly Notices of the Royal Astronomical Society . 462 (4): 3441–3456. arXiv: 1608.01518 . Bibcode:2016MNRAS.462.3441D. doi: 10.1093/mnras/stw1972 .
  9. ↑ Christou, Apostolos A.; Asher, David J. (2011). "A long-lived horseshoe companion to the Earth". Monthly Notices of the Royal Astronomical Society . 414 (4): 2965–2969. arXiv: 1104.0036 . Bibcode:2011MNRAS.414.2965C. doi: 10.1111/j.1365-2966.2011.18595.x . S2CID   13832179.
  10. 1 2 "Small Asteroid is Earth's Constant Companion". Jet Propulsion Laboratory .
  11. 1 2 de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (September 2012). "(309239) 2007 RW10: a large temporary quasi-satellite of Neptune". Astronomy and Astrophysics Letters . 545: L9. arXiv: 1209.1577 . Bibcode:2012A&A...545L...9D. doi:10.1051/0004-6361/201219931. S2CID   118374080.
  12. ↑ Wiegert, P.; Innanen, K. (2000). "The stability of quasi satellites in the outer solar system". The Astronomical Journal . 119 (4): 1978–1984. Bibcode:2000AJ....119.1978W. doi: 10.1086/301291 .
  13. ↑ Green, LM; Zakharov, AV; Pichkhadze, KM. Что мы ищем на Фобосе [What we are looking for [on] Phobos] (in Russian). Archived from the original on 2009-07-20.
  14. 1 2 3 4 de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2012). "Plutino 15810 (1994 JR1), an accidental quasi-satellite of Pluto". Monthly Notices of the Royal Astronomical Society: Letters . 427 (1): L85. arXiv: 1209.3116 . Bibcode:2012MNRAS.427L..85D. doi: 10.1111/j.1745-3933.2012.01350.x . S2CID   118570875.
  15. ↑ "Pluto's fake moon". Archived from the original on 2013-01-05. Retrieved 2012-09-24.
  16. ↑ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2016). "The analemma criterion: accidental quasi-satellites are indeed true quasi-satellites". Monthly Notices of the Royal Astronomical Society . 462 (3): 3344–3349. arXiv: 1607.06686 . Bibcode:2016MNRAS.462.3344D. doi: 10.1093/mnras/stw1833 .
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