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Yarkovsky–O'Keefe–Radzievskii–Paddack effect

January 30, 2023

Not to be confused with Yarkovsky effect.

The Yarkovsky–O'Keefe–Radzievskii–Paddack effect, or YORP effect for short, changes the rotation state of a small astronomical body – that is, the body's spin rate and the obliquity of its pole(s) – due to the scattering of solar radiation off its surface and the emission of its own thermal radiation.

A spherical asteroid with two wedge-shaped projections. Re-radiated light from the "B" fin has the same magnitude as the "A" fin, but is not parallel to the incoming light. This produces a torque on the object.

The YORP effect is typically considered for asteroids with their heliocentric orbit in the Solar System. The effect is responsible for the creation of binary and tumbling asteroids as well as for changing an asteroid's pole towards 0°, 90°, or 180° relative to the ecliptic plane and so modifying its heliocentric radial drift rate due to the Yarkovsky effect.

Term

The term was coined by David P. Rubincam in 2000[1] to honor four important contributors to the concepts behind the so-named YORP effect. In the 19th century, Ivan Yarkovsky realized that the thermal radiation escaping from a body warmed by the Sun carries off momentum as well as heat. Translated into modern physics, each emitted photon possesses a momentum p = E/c where E is its energy and c is the speed of light. Vladimir Radzievskii applied the idea to rotation based on changes in albedo[2] and Stephen Paddack realized that shape was a much more effective means of altering a body's spin rate.[3] Stephen Paddack and John O'Keefe suggested that the YORP effect leads to rotational bursting and by repeatedly undergoing this process, small asymmetric bodies are eventually reduced to dust.[4][5]

Physical mechanism

In principle, electromagnetic radiation interacts with the surface of an asteroid in three significant ways: radiation from the Sun is (1) absorbed and (2) diffusively reflected by the surface of the body and the body's internal energy is (3) emitted as thermal radiation. Since photons possess momentum, each of these interactions leads to changes in the angular momentum of the body relative to its center of mass. If considered for only a short period of time, these changes are very small, but over longer periods of time, these changes may integrate to significant changes in the angular momentum of the body. For bodies in a heliocentric orbit, the relevant long period of time is the orbital period (i.e. year), since most asteroids have rotation periods (i.e. days) shorter than their orbital periods. Thus, for most asteroids, the YORP effect is the secular change in the rotation state of the asteroid after averaging the solar radiation torques over first the rotational period and then the orbital period.

Observations

In 2007 there was direct observational confirmation of the YORP effect on the small asteroids 54509 YORP (then designated 2000 PH5)[6][7] and 1862 Apollo.[8] The spin rate of 54509 YORP will double in just 600,000 years, and the YORP effect can also alter the axial tilt and precession rate, so that the entire suite of YORP phenomena can send asteroids into interesting resonant spin states, and helps explain the existence of binary asteroids.[9]

Observations show that asteroids larger than 125 km in diameter have rotation rates that follow a Maxwellian frequency distribution, while smaller asteroids (in the 50 to 125 km size range) show a small excess of fast rotators. The smallest asteroids (size less than 50 km) show a clear excess of very fast and slow rotators, and this becomes even more pronounced as smaller-sized populations are measured. These results suggest that one or more size-dependent mechanisms are depopulating the centre of the spin rate distribution in favour of the extremes. The YORP effect is a prime candidate. It is not capable of significantly modifying the spin rates of large asteroids by itself, so a different explanation must be sought for objects such as 253 Mathilde.

In late 2013 asteroid P/2013 R3 was observed breaking apart, likely because of a high rotation speed from the YORP effect.[10]

Examples

Assume a rotating spherical asteroid has two wedge-shaped fins attached to its equator, irradiated by parallel rays of sunlight. The reaction force from photons departing from any given surface element of the spherical core will be normal to the surface, such that no torque is produced (the force vectors all pass through the centre of mass).

Thermally-emitted photons reradiated from the sides of the wedges, however, can produce a torque, as the normal vectors do not pass through the centre of mass. Both fins present the same cross section to the incoming light (they have the same height and width), and so absorb and reflect the same amount of energy each and produce an equal force. Due to the fin surfaces being oblique, however, the normal forces from the reradiated photons do not cancel out. In the diagram, Fin A's outgoing radiation produces an equatorial force parallel to the incoming light and no vertical force, but Fin B's force has a smaller equatorial component and a vertical component. The unbalanced forces on the two fins lead to torque and the object spins. The torque from the outgoing light does not average out, even over a full rotation, so the spin accelerates over time.[11]

An object with some "windmill" asymmetry can therefore be subjected to minuscule torque forces that will tend to spin it up or down as well as make its axis of rotation precess. The YORP effect is zero for a rotating ellipsoid if there are no irregularities in surface temperature or albedo.

In the long term, the object's changing obliquity and rotation rate may wander randomly, chaotically or regularly, depending on several factors. For example, assuming the Sun remains on its equator, asteroid 951 Gaspra, with a radius of 6 km and a semi-major axis of 2.21 AU, would in 240 Ma (240 million years) go from a rotation period of 12 h to 6 h and vice versa. If 243 Ida were given the same radius and orbit values as Gaspra, it would spin up or down twice as fast, while a body with Phobos' shape would take several billion years to change its spin by the same amount.

Size as well as shape affects the amount of the effect. Smaller objects will spin up or down much more quickly. If Gaspra were smaller by a factor of 10 (to a radius of 500 m), its spin will halve or double in just a few million years. Similarly, the YORP effect intensifies for objects closer to the Sun. At 1 AU, Gaspra would double/halve its spin rate in a mere 100,000 years. After one million years, its period may shrink to ~2 h, at which point it could start to break apart.[citation needed] According to a 2019 model, the YORP effect is likely to cause "widespread fragmentation of asteroids" as the Sun expands into a luminous red giant, and may explain the dust disks and apparent infalling matter observed at many white dwarfs.[12][13]

This is one mechanism through which binary asteroids may form, and it may be more common than collisions and planetary near-encounter tidal disruption as the primary means of binary formation.

Asteroid 2000 PH5 was later named 54509 YORP to honor its part in the confirmation of this phenomenon.

See also

  • 54509 YORP – Earth co-orbital asteroid
  • 101955 Bennu – Most hazardous near-Earth asteroid
  • 25143 Itokawa - Smallest asteroid to be visited by a spacecraft
  • Radiation pressure – Pressure exerted upon any surface exposed to electromagnetic radiation
  • Radiometer – Device for measuring the radiant flux (power) of electromagnetic radiation
  • Yarkovsky effect – Force acting on a rotating body in space

Notes

  1. ^ Rubincam, D (2000). "Radiative Spin-up and Spin-down of Small Asteroids". Icarus. 148 (1): 2–11. Bibcode:2000Icar..148....2R. doi:10.1006/icar.2000.6485. from the original on 2020-02-26. Retrieved 2019-12-11.
  2. ^ Radzievskii (1954)
  3. ^ Paddack, S. J. (1969-01-01). "Rotational bursting of small celestial bodies: Effects of radiation pressure". Journal of Geophysical Research. 74 (17): 4379–4381. Bibcode:1969JGR....74.4379P. doi:10.1029/JB074i017p04379. ISSN 0148-0227.
  4. ^ S. J. Paddack, J. W. Rhee, Geophys. Res. Lett 2, 365 (1975)
  5. ^ Okeefe, J. A. (1975-04-01). "Tektites and their origin". NASA STI/Recon Technical Report N. 75: 23444. Bibcode:1975STIN...7523444O.
  6. ^ Lowry, S. C.; Fitzsimmons, A.; Pravec, P.; Vokrouhlicky, D.; Boehnhardt, H.; Taylor, P. A.; Margot, J.-L.; Galad, A.; Irwin, M.; Irwin, J.; Kusnirak, P. (2007). "Direct Detection of the Asteroidal YORP Effect" (PDF). Science. 316 (5822): 272–274. Bibcode:2007Sci...316..272L. doi:10.1126/science.1139040. ISSN 0036-8075. PMID 17347414. S2CID 26687221. (PDF) from the original on 2019-09-23. Retrieved 2019-09-23.
  7. ^ Taylor, P. A.; Margot, J.-L.; Vokrouhlicky, D.; Scheeres, D. J.; Pravec, P.; Lowry, S. C.; Fitzsimmons, A.; Nolan, M. C.; Ostro, S. J.; Benner, L. A. M.; Giorgini, J. D.; Magri, C. (2007). "Spin Rate of Asteroid (54509) 2000 PH5 Increasing Due to the YORP Effect". Science. 316 (5822): 274–277. Bibcode:2007Sci...316..274T. doi:10.1126/science.1139038. ISSN 0036-8075. PMID 17347415. S2CID 29191700.
  8. ^ Kaasalainen, Mikko; Ďurech, Josef; Warner, Brian D.; Krugly, Yurij N.; Gaftonyuk, Ninel M. (2007). "Acceleration of the rotation of asteroid 1862 Apollo by radiation torques". Nature. 446 (7134): 420–422. Bibcode:2007Natur.446..420K. doi:10.1038/nature05614. PMID 17344861. S2CID 4420270.
  9. ^ Rubincam, D. P.; Paddack, S. J. (2007). "As Tiny Worlds Turn". Science. 316 (5822): 211–212. CiteSeerX 10.1.1.205.5777. doi:10.1126/science.1141930. PMID 17431161. S2CID 118802966.
  10. ^ "Hubble witnesses an asteroid mysteriously disintegrating". from the original on 2014-03-12. Retrieved 2014-03-06.
  11. ^ Rubincam, D (2000). "Radiative Spin-up and Spin-down of Small Asteroids". Icarus. Elsevier BV. 148 (1): 2–11. Bibcode:2000Icar..148....2R. doi:10.1006/icar.2000.6485. from the original on 2020-02-26. Retrieved 2019-12-11.
  12. ^ Veras, Dimitri; Scheeres, Daniel J (February 2020). "Post-main-sequence debris from rotation-induced YORP break-up of small bodies – II. Multiple fissions, internal strengths, and binary production". Monthly Notices of the Royal Astronomical Society. 492 (2): 2437–2445. arXiv:2001.00949. doi:10.1093/mnras/stz3565.
  13. ^ Timmer, John (18 February 2020). "When the Sun expands, it will trash all the asteroids". Ars Technica. from the original on 20 February 2020. Retrieved 20 February 2020.

References

  • O'Keefe, John A. (1976). Tektites and Their Origin. Elsevier.
  • Paddack, Stephen J (1969). "Rotational bursting of small celestial bodies: Effects of radiation pressure". J. Geophys. Res. 74 (17): 4379–4381. Bibcode:1969JGR....74.4379P. doi:10.1029/jb074i017p04379.
  • Radzievskii, V. V. (1954). "A mechanism for the disintegration of asteroids and meteorites". Doklady Akademii Nauk SSSR. 97: 49–52.
  • Rubincam, David P (2000). "Radiative spin-up and spin-down of small asteroids". Icarus. 148 (1): 2–11. Bibcode:2000Icar..148....2R. doi:10.1006/icar.2000.6485.

Further reading

  • Statler, Thomas S. (2009-03-05). "Extreme Sensitivity of the YORP Effect to Small-Scale Topography". Icarus. 202 (2): 502–513. arXiv:0903.1119. Bibcode:2009Icar..202..502S. doi:10.1016/j.icarus.2009.03.003. S2CID 18935544.
  • Vokrouhlicky, David; Bottke, William F. (2012). "Yarkovsky and YORP effects". Scholarpedia. 7 (5): 10599. arXiv:1502.01249. Bibcode:2012SchpJ...710599B. doi:10.4249/scholarpedia.10599.

External links

January 30, 2023
yarkovsky, keefe, radzievskii, paddack, effect, confused, with, yarkovsky, effect, request, that, this, article, title, changed, yorp, effect, under, discussion, please, move, this, article, until, discussion, closed, yorp, effect, short, changes, rotation, st. Not to be confused with Yarkovsky effect A request that this article title be changed to YORP effect is under discussion Please do not move this article until the discussion is closed The Yarkovsky O Keefe Radzievskii Paddack effect or YORP effect for short changes the rotation state of a small astronomical body that is the body s spin rate and the obliquity of its pole s due to the scattering of solar radiation off its surface and the emission of its own thermal radiation A spherical asteroid with two wedge shaped projections Re radiated light from the B fin has the same magnitude as the A fin but is not parallel to the incoming light This produces a torque on the object The YORP effect is typically considered for asteroids with their heliocentric orbit in the Solar System The effect is responsible for the creation of binary and tumbling asteroids as well as for changing an asteroid s pole towards 0 90 or 180 relative to the ecliptic plane and so modifying its heliocentric radial drift rate due to the Yarkovsky effect Contents 1 Term 2 Physical mechanism 3 Observations 4 Examples 5 See also 6 Notes 7 References 8 Further reading 9 External linksTerm EditThe term was coined by David P Rubincam in 2000 1 to honor four important contributors to the concepts behind the so named YORP effect In the 19th century Ivan Yarkovsky realized that the thermal radiation escaping from a body warmed by the Sun carries off momentum as well as heat Translated into modern physics each emitted photon possesses a momentum p E c where E is its energy and c is the speed of light Vladimir Radzievskii applied the idea to rotation based on changes in albedo 2 and Stephen Paddack realized that shape was a much more effective means of altering a body s spin rate 3 Stephen Paddack and John O Keefe suggested that the YORP effect leads to rotational bursting and by repeatedly undergoing this process small asymmetric bodies are eventually reduced to dust 4 5 Physical mechanism EditIn principle electromagnetic radiation interacts with the surface of an asteroid in three significant ways radiation from the Sun is 1 absorbed and 2 diffusively reflected by the surface of the body and the body s internal energy is 3 emitted as thermal radiation Since photons possess momentum each of these interactions leads to changes in the angular momentum of the body relative to its center of mass If considered for only a short period of time these changes are very small but over longer periods of time these changes may integrate to significant changes in the angular momentum of the body For bodies in a heliocentric orbit the relevant long period of time is the orbital period i e year since most asteroids have rotation periods i e days shorter than their orbital periods Thus for most asteroids the YORP effect is the secular change in the rotation state of the asteroid after averaging the solar radiation torques over first the rotational period and then the orbital period Observations EditIn 2007 there was direct observational confirmation of the YORP effect on the small asteroids 54509 YORP then designated 2000 PH5 6 7 and 1862 Apollo 8 The spin rate of 54509 YORP will double in just 600 000 years and the YORP effect can also alter the axial tilt and precession rate so that the entire suite of YORP phenomena can send asteroids into interesting resonant spin states and helps explain the existence of binary asteroids 9 Observations show that asteroids larger than 125 km in diameter have rotation rates that follow a Maxwellian frequency distribution while smaller asteroids in the 50 to 125 km size range show a small excess of fast rotators The smallest asteroids size less than 50 km show a clear excess of very fast and slow rotators and this becomes even more pronounced as smaller sized populations are measured These results suggest that one or more size dependent mechanisms are depopulating the centre of the spin rate distribution in favour of the extremes The YORP effect is a prime candidate It is not capable of significantly modifying the spin rates of large asteroids by itself so a different explanation must be sought for objects such as 253 Mathilde In late 2013 asteroid P 2013 R3 was observed breaking apart likely because of a high rotation speed from the YORP effect 10 Examples EditAssume a rotating spherical asteroid has two wedge shaped fins attached to its equator irradiated by parallel rays of sunlight The reaction force from photons departing from any given surface element of the spherical core will be normal to the surface such that no torque is produced the force vectors all pass through the centre of mass Thermally emitted photons reradiated from the sides of the wedges however can produce a torque as the normal vectors do not pass through the centre of mass Both fins present the same cross section to the incoming light they have the same height and width and so absorb and reflect the same amount of energy each and produce an equal force Due to the fin surfaces being oblique however the normal forces from the reradiated photons do not cancel out In the diagram Fin A s outgoing radiation produces an equatorial force parallel to the incoming light and no vertical force but Fin B s force has a smaller equatorial component and a vertical component The unbalanced forces on the two fins lead to torque and the object spins The torque from the outgoing light does not average out even over a full rotation so the spin accelerates over time 11 An object with some windmill asymmetry can therefore be subjected to minuscule torque forces that will tend to spin it up or down as well as make its axis of rotation precess The YORP effect is zero for a rotating ellipsoid if there are no irregularities in surface temperature or albedo In the long term the object s changing obliquity and rotation rate may wander randomly chaotically or regularly depending on several factors For example assuming the Sun remains on its equator asteroid 951 Gaspra with a radius of 6 km and a semi major axis of 2 21 AU would in 240 Ma 240 million years go from a rotation period of 12 h to 6 h and vice versa If 243 Ida were given the same radius and orbit values as Gaspra it would spin up or down twice as fast while a body with Phobos shape would take several billion years to change its spin by the same amount Size as well as shape affects the amount of the effect Smaller objects will spin up or down much more quickly If Gaspra were smaller by a factor of 10 to a radius of 500 m its spin will halve or double in just a few million years Similarly the YORP effect intensifies for objects closer to the Sun At 1 AU Gaspra would double halve its spin rate in a mere 100 000 years After one million years its period may shrink to 2 h at which point it could start to break apart citation needed According to a 2019 model the YORP effect is likely to cause widespread fragmentation of asteroids as the Sun expands into a luminous red giant and may explain the dust disks and apparent infalling matter observed at many white dwarfs 12 13 This is one mechanism through which binary asteroids may form and it may be more common than collisions and planetary near encounter tidal disruption as the primary means of binary formation Asteroid 2000 PH5 was later named 54509 YORP to honor its part in the confirmation of this phenomenon See also Edit54509 YORP Earth co orbital asteroid 101955 Bennu Most hazardous near Earth asteroid 25143 Itokawa Smallest asteroid to be visited by a spacecraft Radiation pressure Pressure exerted upon any surface exposed to electromagnetic radiation Radiometer Device for measuring the radiant flux power of electromagnetic radiation Yarkovsky effect Force acting on a rotating body in spaceNotes Edit Rubincam D 2000 Radiative Spin up and Spin down of Small Asteroids Icarus 148 1 2 11 Bibcode 2000Icar 148 2R doi 10 1006 icar 2000 6485 Archived from the original on 2020 02 26 Retrieved 2019 12 11 Radzievskii 1954 Paddack S J 1969 01 01 Rotational bursting of small celestial bodies Effects of radiation pressure Journal of Geophysical Research 74 17 4379 4381 Bibcode 1969JGR 74 4379P doi 10 1029 JB074i017p04379 ISSN 0148 0227 S J Paddack J W Rhee Geophys Res Lett 2 365 1975 Okeefe J A 1975 04 01 Tektites and their origin NASA STI Recon Technical Report N 75 23444 Bibcode 1975STIN 7523444O Lowry S C Fitzsimmons A Pravec P Vokrouhlicky D Boehnhardt H Taylor P A Margot J L Galad A Irwin M Irwin J Kusnirak P 2007 Direct Detection of the Asteroidal YORP Effect PDF Science 316 5822 272 274 Bibcode 2007Sci 316 272L doi 10 1126 science 1139040 ISSN 0036 8075 PMID 17347414 S2CID 26687221 Archived PDF from the original on 2019 09 23 Retrieved 2019 09 23 Taylor P A Margot J L Vokrouhlicky D Scheeres D J Pravec P Lowry S C Fitzsimmons A Nolan M C Ostro S J Benner L A M Giorgini J D Magri C 2007 Spin Rate of Asteroid 54509 2000 PH5 Increasing Due to the YORP Effect Science 316 5822 274 277 Bibcode 2007Sci 316 274T doi 10 1126 science 1139038 ISSN 0036 8075 PMID 17347415 S2CID 29191700 Kaasalainen Mikko Durech Josef Warner Brian D Krugly Yurij N Gaftonyuk Ninel M 2007 Acceleration of the rotation of asteroid 1862 Apollo by radiation torques Nature 446 7134 420 422 Bibcode 2007Natur 446 420K doi 10 1038 nature05614 PMID 17344861 S2CID 4420270 Rubincam D P Paddack S J 2007 As Tiny Worlds Turn Science 316 5822 211 212 CiteSeerX 10 1 1 205 5777 doi 10 1126 science 1141930 PMID 17431161 S2CID 118802966 Hubble witnesses an asteroid mysteriously disintegrating Archived from the original on 2014 03 12 Retrieved 2014 03 06 Rubincam D 2000 Radiative Spin up and Spin down of Small Asteroids Icarus Elsevier BV 148 1 2 11 Bibcode 2000Icar 148 2R doi 10 1006 icar 2000 6485 Archived from the original on 2020 02 26 Retrieved 2019 12 11 Veras Dimitri Scheeres Daniel J February 2020 Post main sequence debris from rotation induced YORP break up of small bodies II Multiple fissions internal strengths and binary production Monthly Notices of the Royal Astronomical Society 492 2 2437 2445 arXiv 2001 00949 doi 10 1093 mnras stz3565 Timmer John 18 February 2020 When the Sun expands it will trash all the asteroids Ars Technica Archived from the original on 20 February 2020 Retrieved 20 February 2020 References EditO Keefe John A 1976 Tektites and Their Origin Elsevier Paddack Stephen J 1969 Rotational bursting of small celestial bodies Effects of radiation pressure J Geophys Res 74 17 4379 4381 Bibcode 1969JGR 74 4379P doi 10 1029 jb074i017p04379 Radzievskii V V 1954 A mechanism for the disintegration of asteroids and meteorites Doklady Akademii Nauk SSSR 97 49 52 Rubincam David P 2000 Radiative spin up and spin down of small asteroids Icarus 148 1 2 11 Bibcode 2000Icar 148 2R doi 10 1006 icar 2000 6485 Further reading EditStatler Thomas S 2009 03 05 Extreme Sensitivity of the YORP Effect to Small Scale Topography Icarus 202 2 502 513 arXiv 0903 1119 Bibcode 2009Icar 202 502S doi 10 1016 j icarus 2009 03 003 S2CID 18935544 Vokrouhlicky David Bottke William F 2012 Yarkovsky and YORP effects Scholarpedia 7 5 10599 arXiv 1502 01249 Bibcode 2012SchpJ 710599B doi 10 4249 scholarpedia 10599 External links EditKlotz Irene 2007 03 07 Asteroid Spin Changed by Sunlight Discovery Communications LLC Archived from the original on 2008 04 26 Asteroid rotation discovery reported Retrieved from https en wikipedia org w index php title Yarkovsky O 27Keefe Radzievskii Paddack effect amp oldid 1134316679, wikipedia, wiki, book, books, library,

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