Planet nine

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Fantasy representation of Planet Nine, which shows its probable distance. ( See labeled version .)

Planet Nine ( English Planet Nine ) is the preliminary name of a hypothetical planet-like celestial body , which is believed to be far outside the orbit of the planet Neptune in the outer solar system .

The planet has not yet been observed directly. Rather, it is postulated to explain a statistical abnormality regarding the orbital elements of a group of trans-Neptunian objects . Most noticeable are the orbits with large semiaxes of over 250 astronomical units (AU). At the beginning of 2016, six such objects were known, the dwarf planet candidate (90377) Sedna , 2012 VP 113 , (474640) 2004 VN 112 , (523622) 2007 TG 422 , 2013 RF 98 and 2010 GB 174 . This group is called Sednoiden after Sedna . They all have orbits whose apsidal lines (connecting lines between the points closest to and furthest from the sun) point in similar directions, as well as inclinations ( orbital inclination towards the ecliptic plane ) between +11 and +30 degrees. Without the postulated planet, Jupiter and Saturn would cause a wide distribution of the apsidal lines and inclinations.

For older supposed references to undiscovered planets of our sun that have nothing to do with the statistics of the trans-Neptunian objects , see Transpluto and Nice model .

Previous theories

Orbit elements of the elliptical orbit of a celestial body around a central body

Gomes et al.

A number of objects, called distant detached objects by the astronomer Michael E. Brown , were examined by a group around Rodney Gomes as early as 2006 , which led to the assumption of another large object of planetary mass . Since around 2012, Gomes has specifically suspected a large planet that would influence the orbits of at least six of these trans-Neptunian objects. He suggested a planet the size of Mars or a little further out, the size of Neptune, as the cause.

Trujillo / Sheppard

The analysis of the orbital data of 2012 VP 113 also prompted Chad Trujillo and Scott S. Sheppard in 2014 to postulate another planet, which should be larger than Earth, in a distant orbit.

Marcos et al.

In the same year, astronomers from the Complutense University of Madrid confirmed that the explanation of the present orbits by coincidence is unlikely and cannot be explained by a streetlight effect , but is a real characteristic of this population, which has its possible origin in the context of the Kozai effect . This suggests that at least two other Trans-Neptunian planets may exist.

Jacques Laskar et al.

Jacques Laskar and other employees of the Paris Observatory came to the conclusion that a ninth planet could exist by evaluating the data from the “ Cassini ” space probe , which had been collected up to April 2014. Using mathematical models, they excluded areas for a further search and thus reduced the search area by 50%. They tried (unsuccessfully) to keep the space probe in operation until 2020, as the probe continuously provided relevant data and they hope that this will provide further information.

Batygin and Brown's theory

Konstantin Batygin and Michael E. Brown , astronomers at the California Institute of Technology  ( Caltech ), checked this data and announced on January 19, 2016 that they could use mathematical modeling and computer simulations of such a planet to explain the specifics of the orbits and have possible orbital elements of the planet as well as its mass. According to a statistical analysis by Batygin and Brown, the probability of a random constellation is only 0.007%. Since then, other objects such as B. 2014 SR 349 found that support this theory. However, the discoverers of the 2013 SY 99 object do not see any support for the theory in its orbit data.

Orbit parameters of highly extreme trans-Neptunian objects with perihelias greater than 30 AU and major semi-axes greater than 250 AU Note: Data taken from MPC, the information is best fits and therefore subject to great uncertainties
object Orbital period T
(years)		 Semi-axis a
(AE)		 Perihelion
q (AE)		 Aphelion
Q (AE)		 eccentricity
e		 Argument of
the periapsis
? (°)		 Inclination
i (°)		 Length of the
rise Node
Ω (°)		 Perihelion
π = ω + Ω (°)		 Absolute brightness
H (mag)
(90377) Sedna 10,590 482.24 76.08 888.39 0.84 311.6 11.9 144.4 96.0 1.5
(474640) 2004 VN 112 5,602 315.41 47.31 583.51 0.85 326.9 25.6 66.0 32.9 6.5
(523622) 2007 TG 422 10.165 469.26 35.55 902.96 0.92 285.6 18.6 112.9 38.5 6.5
2010 GB 174 6,824 359.75 48.79 670.72 0.86 347.7 21.6 130.8 118.5 6.5
2012 VP 113 ("Biden") 4.106 256.40 80.44 432.37 0.69 293.6 24.1 90.7 24.3 4.0
2013 FT 28 5,558 313.77 43.52 584.02 0.86 40.3 17.3 217.8 258.1 6.7
2013 RF 98 6,556 350.30 36.08 664.52 0.90 311.7 29.6 67.6 19.3 8.7
2013 SY 99 ("uo3l91") 17,604 676.71 49.96 1,303.45 0.93 32.3 4.2 29.5 61.8 6.7
2014 FE 72 101.195 2,171.57 36.28 4,306.86 0.98 134.3 20.6 336.8 111.1 6.1
2014 SR 349 5,064 294.90 47.65 542.14 0.84 341.1 18.0 34.8 15.9 6.7
2015 GT 50 ("o5p060") 6,073 332.85 38.46 627.24 0.88 129.3 8.8 46.1 175.4 8.5
2015 KG 163 ("o5m52") 23,718 825.50 40.50 1,610.50 0.95 32.0 14.0 219.1 251.1 8.2
2015 RX 245 ("o5t52") 8,210 406.96 45.52 768.40 0.89 65.3 12.2 8.6 73.9 6.2
2015 BP 519 ("Caju") 8,932 430.48 35.14 825.81 0.92 348.4 54.1 135.2 123.6 4.4
(541132) Leleākūhonua 36,182 1,093.94 64.94 2,122.94 0.94 118.2 11.6 300.8 59.0 5.3

Theoretical mass, diameter, brightness

The search for planet nine assumes a planet with mass and diameter similar to those of the blue ice giants Uranus and Neptune .

Brown assumes that the planet is an ice giant with about 10  M ⊕ (Earth's mass) that will be discovered within the next five years (as of January 2016). With this mass and a similar internal structure as assumed for Uranus and Neptune, it could be slightly smaller than Neptune with a diameter of about 3.7 earth diameters (46,600 km) , have a surface temperature of 47 K (−226 ° C) and its radiation maximum in the far infrared at 62 µm.

Theoretical orbit

Orbits of six trans-Neptunian objects around the sun, supplemented by the hypothetical orbit of planet nine

Based on the Batygin and Brown model , the orbit of the presumed planet must be completely outside of the orbit of Neptune , currently the outermost verified planet in the solar system. For reasons that lie in the dynamics of the solar system, a large semiaxis of the orbit between 400 and 1500 AU is possible, with an orbital eccentricity of 0.5 to about 0.8. It is assumed that a planet in this distance range from the sun cannot have formed, but only entered such an orbit after its formation through orbital disruption or (with less probability) as the capture of a planemos that originated outside the solar system .

The best results were achieved by model parameters with a large semi-axis of 700 AU (about 4  light days ). The mean distance to the sun is about 20 times that of Neptune. Furthermore, they give an orbital eccentricity of e  = 0.6 with an orbital inclination of i  = 30 ° in relation to the orbit plane of the other large planets and an argument of the periapsis of ω  = 150 ° as model parameters . According to Kepler's 3rd law, it follows that the hypothetical planet would have an orbital period on the order of 20,000 years.

Calculation of the orbital mechanics by Renu Malhotra in relation to the presumably resonant orbits of the six sednoids found first resulted in the most likely orbit with a semi-axis of about 665 AU. The period of rotation of around 17,100 years would then be in small integer ratios to those of these six objects. In this solution, the orbit inclination relative to the ecliptic is either in the plane of the conspicuous sednoid cluster at around 18 ° or at around 48 °.

The orbit of such a planet could have been closer to the sun in the early days of the solar system than it is today and only later increased by the gravitational effects of the other large planets.

Existence probability, search and findability

According to Brown, the probability that the planet exists is over 90%, and its apparent brightness could be large enough to be able to discover the body with the most sensitive telescopes at the time of the statement (January 2016). The Subaru Telescope in Hawaii has already started the search for Planet Nine. Other astronomers almost rule out finding it even with the latest space telescopes. A celestial body is very faint at this distance because it reflects extremely little sunlight. In addition, Batygin / Brown could not give an exact position in the sky at which to search for the presumed planet. Since no planet had been discovered in the Catalina Sky Survey with Pan-STARRS and the Wide-Field Infrared Survey Explorer (WISE), Planet Nine must be in the more distant part of its orbit and possibly in front of the band of the Milky Way.

At a surface temperature of 40 K, a distance of 700 AU and Neptune size , millimeter-wave radiation with a flux density of around 30  mJy would be expected, with which such an object could be identified in the context of measurements of cosmic background radiation .

The Citizen Science project Backyard Worlds: Planet 9 of NASA, launched in February 2017 to evaluate images from the Space Telescope Wide-Field Infrared Survey Explorer (WISE), revealed 95 brown dwarfs as of August 2020 , but no evidence of their existence from Planet Nine.

Planet status

It has the provisional designation "Planet Nine" because of the nine planets (from the 1930s) the last discovered Pluto was placed in the group of dwarf planets in 2006 , since even more objects of its size and orbit characteristics had been discovered. There are therefore Usance of scientific astronomy so only eight planets in the solar system. Planet Nine could, however, meet the currently valid criteria for a regular planet : In particular, the proof that it - as required by the definition of the International Astronomical Union (IAU) - has cleared its orbit of small bodies, however, would go beyond the confirmation of its existence Mean effort. It could also represent a new class of solar system bodies or make a further adjustment of the current planetary criteria necessary. Brown himself, who was instrumental in the reclassification of Pluto, stated shortly after the publication that he considers the planet to be regular:

“Planet Nine is forcing any objects that cross its orbit to push into these misaligned positions. It fits that concept perfectly. "

“Planet nine forces all objects that cross its orbit into these displaced positions. It fits perfectly into this concept. "

Naming

Should the existence of Planet Nine be confirmed, the IAU will be responsible for naming the planet. Batygin and Brown speculate that the planet will be named after a Roman deity , similar to those known so far .

Further speculation

In July 2016, Elizabeth Bailey, Konstantin Batygin and Michael E. Brown as well as Rodney Gomes, Rogerio Deienno and Alessandro Morbidelli pointed out that the existence of the postulated planet with its assumed high inclination for "tilting" the ecliptic by 7.2 ° or the invariable plane of the solar system at 5.9 ° to the equatorial plane of the sun could be responsible. For this, the perihelion of Planet Nine would have to be around 250 AU. In addition to the inclination of the orbit, the planet must also have a corresponding mass so that it influences the entire solar system in this way, scientists at the California Institute of Technology explained in October 2016.

A work published in September 2019 discusses the possibility that the object could be a primordial black hole captured by the solar system .

See also

literature

Web links

Commons : Planet Nine  - collection of images, videos and audio files

Individual evidence

  1. ↑ Alexandra Witze: References to the ninth planet are increasing. In: Spektrum.de. Spectrum of Science , January 21, 2016, accessed January 21, 2016 : "They call it Planet Nine."
  2. ↑ a b c d e Konstantin Batygin, Michael E. Brown: Evidence for a Distant Giant Planet in the Solar System. In: The Astronomical Journal. Volume 151, No. 2, 2016, pp. 22-34, doi: 10.3847 / 0004-6256 / 151/2/22 , arxiv : 1601.05438
  3. ↑ Sedna. In: small body database. Jet Propulsion Laboratory , accessed January 25, 2016 .
  4. ↑ (2013 RF98). In: small body database. Jet Propulsion Laboratory , accessed January 25, 2016 .
  5. ↑ Rodney S. Gomes, John J. Matese, Jack J. Lissauer: A distant planetary-mass solar companion may have produced distant detached objects. In: Icarus. Volume 184, number 2, October 2006, pp. 589-601, doi: 10.1016 / j.icarus.2006.05.026 .
  6. ^ A b Rodney S. Gomes, JS Soares: Signatures Of A Putative Planetary Mass Solar Companion On The Orbital Distribution Of Tno's And Centaurs. In: American Astronomical Society, DDA meeting # 43, id.5.01. , 2012 bibcode : 2012DDA .... 43.0501G .
  7. ↑ Rodney S. Gomes, Jean S. Soares, Ramon Brasser: The observation of large semi-major axis Centaurs: Testing for the signature of a planetary-mass solar companion. In: Icarus. 258, September 15, 2015, pp. 37-49, doi: 10.1016 / j.icarus.2015.06.020 .
  8. ↑ Florian Freistetter: Some information on the discovery of the "new" planet in our solar system. In: scienceblogs.de. ScienceBlogs , January 21, 2016, accessed January 21, 2016 .
  9. ↑ New planet found in our Solar System? At: News.NationalGeographic.com. May 12, 2012. Retrieved January 25, 2016.
  10. ↑ cf. on this, reference Batygin, Brown in: The Astronomical Journal. 2016, p. 10, col. 2.
  11. ↑ Planet Nine is bigger. At: BlobTheScientist.blogspot.com. January 23, 2016, accessed January 23, 2015.
  12. ^ Chadwick A. Trujillo, Scott S. Sheppard, A Sedna-like body with a perihelion of 80 astronomical units. In: Nature. 507, 2014, pp. 471-474, doi: 10.1038 / nature13156 .
  13. ↑ C. de la Fuente Marcos, R. de la Fuente Marcos: Extreme trans-Neptunian objects and the Kozai mechanism: signaling the presence of trans-Plutonian planets. In: Monthly Notices of the Royal Astronomical Society: Letters. 443, 2014, p. L59, doi: 10.1093 / mnrasl / slu084 , arxiv : 1406.0715 .
  14. ↑ Search narrows for Planet Nine along sprawling orbit of Thousands of years on: The Guardian , February 24, 2016 Retrieved on February 24, 2016
  15. ↑ A. Fienga, J. Laskar, H. & M. Some Gastineau: Constraints on the location of a possible 9th planet derived from the Cassini data. Astronomy & Astrophysics, 587 (2016), L8 doi: 10.1051 / 0004-6361 / 201628227 , arxiv : 1602.06116
  16. ↑ a b Joel Achenbach, Rachel Feltman: New evidence suggests a ninth planet lurking at the edge of the solar system. In: washingtonpost.com. The Washington Post , January 20, 2016, accessed January 21, 2016 .
  17. ↑ Mike Wall: The Search for Planet Nine: New Finds Boost Case for Distant World. Space.com website, August 29, 2016, accessed September 11, 2016 .
  18. ↑ Michele T. Bannister: Our discovery of a minor planet beyond Neptune shows there might not be a 'Planet Nine' after all. Theconservation.com, April 18, 2017, accessed May 10, 2017 .
  19. ↑ Michele T. Bannister et al .: OSSOS: V. Diffusion in the orbit of a high-perihelion distant Solar System object . April 6, 2017, arxiv : 1704.01952v1 .
  20. ↑ Website of the Minor Planet Center (MPC), list of objects with q> 30 and a> 250. International Astronomical Union (IAU), accessed January 19, 2020 .
  21. ↑ Ian Sample: Evidence suggests huge ninth planet exists past Pluto at solar system's edge. In: TheGuardian.com. The Guardian , January 20, 2016, accessed January 20, 2016 .
  22. ↑ Esther F. Linder, Christoph Mordasini: Evolution and magnitudes of candidate Planet Nine . (PDF) In: Astronomy & Astrophysics . 589, no.A134, April 25, 2016. arxiv : 1602.07465 . bibcode : 2016A & A ... 589A.134L . doi : 10.1051 / 0004-6361 / 201628350 .
  23. ↑ Solar system: What could planet 9 look like? scinexx.de, April 8, 2016, accessed April 8, 2016 .
  24. ↑ Puzzles about the orbit of Planet 9. scinexx.de, May 6, 2016, accessed on May 6, 2016 .
  25. ↑ Renu Malhotra, Kathryn Volk, Xianyu Wang: Corralling a Distant Planet with Extreme Resonant Kuiper Belt Objects . In: The Astrophysical Journal Letters . 824, No. 2, June 15, 2016, p. L22. arxiv : 1603.02196 . bibcode : 2016ApJ ... 824L..22M . doi : 10.3847 / 2041-8205 / 824/2 / L22 .
  26. ↑ David Nesvorný: Young Solar System's Fifth Giant Planet? In: The Astrophysical Journal . Letters. Volume 742, number 2, December 1, 2011, p. L22, doi: 10.1088 / 2041-8205 / 742/2 / L22 ( full text as PDF file ).
  27. ↑ Torsten Harmsen: Dark giant far from the sun. In: Berliner Zeitung . January 22, 2016, p. 25, online version here .
  28. ↑ Mike Brown: The search for Planet Nine. Where is Planet Nine? ( Memento from January 30, 2016 in the Internet Archive ), January 2016 on www.findplanetnine.com
  29. ^ Nicolas B. Cowan, Gil Holder, Nathan A. Kaib: Cosmologists in search of Planet Nine: The case for CMB experiments. In: The Astrophysical Journal Letters (vol. 822, no.1). April 22, 2016. Retrieved April 28, 2016 . doi: 10.3847 / 2041-8205 / 822/1 / L2
  30. ↑ Backyard Worlds: Planet 9. NASA , March 17, 2017, accessed August 20, 2020 .
  31. ↑ Hunt for "Planet 9" - now to participate. scinexx , February 20, 2017, accessed August 20, 2020 .
  32. ↑ 95 dwarfs in our neighborhood. scinexx , August 19, 2020, accessed on August 20, 2020 .
  33. ↑ cf. Robert Walker: Why This New “Planet X” Is No Threat To Earth :) . In: About Science 2.0. January 21, 2016, especially the section If it exists, is it a planet according to the IAU definition? Retrieved January 23, 2015.
  34. ↑ Planet Nine: How to become a planet. On: bbc.co.uk.  - Newsbeat, Jan. 21, 2016.
  35. ↑ Ross Andersen: Planet Nine May Help Us Slingshot Our Way to Interstellar Space. In: TheAtlantic.com. The Atlantic , January 21, 2016, accessed January 21, 2016 .
  36. ^ Solar Obliquity Induced by Planet Nine. arxiv : 1607.03963v2 .
  37. ↑ The inclination of the planetary system relative to the solar equator may be explained by the presence of Planet 9. arxiv : 1607.05111 .
  38. ^ Lan Yuhas: A possible ninth planet may be the reason for a tilt in our solar system. In: TheGuardian.com. October 19, 2016. Retrieved October 20, 2016.
  39. ↑ Jakub Scholtz, James Unwin: What if Planet 9 is a Primordial Black Hole. September 24, 2019, accessed October 8, 2019 . , arxiv : 1909.11090v1
  40. ↑ Jan Dönges: Is "Planet Nine" really a black hole? Spektrum.de , October 1, 2019, accessed on October 9, 2019 .