sign in sign up
<<
Home , Anders Johan Lexell, Chad Trujillo, Gerard Kuiper, Johann Gottfried Galle, Kerberos (moon), Planet Nine

From X to

Nuno Peixinho

Café com Física 2016 The Triumph of Finding Neptune

• Neptune was teh first planet to be discoverd by prediction. • 1781, Anders Johan Lexell saw that there were irregularities in ´ . • 1846, predicted the and location for the unknown planet that would explain such irregularities. • Johann Gottfried Galle and Heinrich Louis d’Arrest find it at the of on the same (at night, of coutrse) they received the news: September 23rd, 1846. • also had predicted Neptune and he has credit for that but… “Planet-X” Planet O, P, Q, R, S, T, and U

• William Pickering is the most prolific postulator of undiscoverd . • From 1908 to 1932, Pickering proposed seven hypothetical planets: O, P, Q, R, S, T and U.

⇒ Planet S Proposed in 1928; given elements in 1931: a=48.3 AU, P=336 yr, M=5M, mag=15.

⇒ Planet O Proposed in 1908; given elements in 1928: a=35.2 AU, P=209 yr, M=0.5M, mag=12. Planet X

• Persival Lowell was searching for his Planet X. • During 1906, using a 5-inch (13 cm) camera. • From 1914 to 1916, a 9-inch (23 cm) telescope.

⇒ Planet X Proposed in 1906; given elements in 1927: a=43 AU, P=282 yr, M=6.6M, mag=12-13. • Never found anything but… did photograph in March and April 1915!!! • He founded the Lowell Observatory as private. Pluto

• , a farm boy who was an amateur , was hired in 1929. • On January 23rd and 29th, 1930, he made teh exposures on which he found Pluto when examining them on February 18th. • The discovery was telegraphed on March 13th, 1930. • It was named Pluto by the 11 year old English girl . Pluto

• Clyde Tombaugh, a farm boy who was an amateur astronomer, was hired in 1929. • On January 23rd and 29th, 1930, he made teh exposures on which he found Pluto when examining them on February 18th. • The discovery was telegraphed on March 13th, 1930. • It was named Pluto by the 11 year old English girl Venetia Burney. Problems with Pluto

I hate theoreticians! • Pluto was 6º off from the predictions. • Pluto was 10 times dimmer as predicted. • Pluto would not perturb other planets. • Pluto had a very elliptical orbit. • Pluto could not be Planet-X. • Pluto might not even be a planet at all! • Tombaugh continue his search for 13 more years.

• James Christy discovers Charon on June 22th, 1978. • The discovery is confirmed with plates from 1965 • 1/2 Pluto’s size, 1/8 Pluto’s mass. Pluto and Charon… in 2002 Pluto and Charon… in 2002 Other

• In 2005, Canup demonstrates that the Pluto-Charon system was formed by a collision. • In 2005, two other moons are discovered, and two more in 2011 and 2012: • • • • • All were presumably formed by the collision, no captures are expected.

• Launched on January 19th, 2006. • Reached Pluto on July 14th, 2015. • In 2019… will reach 2014MU69. Better than a thousand words Charon Nix, Hydra, Kerberos, and Styx The Beyond Neptune

• Leonard (1930), Edgeworth (1943, 1949) and Kuiper (1951) speculate on the existence of othe planets beyond Neptune or Pluto. • After several atempts by different teams in the 80s, Luu and Jewitt dicover the first Kuiper Belt Object (KBO) a.k.a. Trans-Neptunian Object (TNO): 1992QB1. (Oort and Kuiper)

• (1900 – 1992) was famous for proposing the in 1950 — Ernst Öpik also proposed it in 1932. • Gerard Kuiper (1905 – 1973) suggested that may have formed in today’s Kuiper Belt but they should have been all sweapt away by now due to Pluto and Neptune. • Oort disagreed with him.

Stubborn old man! Your ideas are rubbish. Kuiper Belt Objects or Trans-Neptunian Objets Some are big, but most are small

Nix Hydra Styx Kerberos Hi’iaka Pluto

Charon

Makemake Quaoar

Dysnomia

Eris 1000 km

3000 km There are many dynamical families

• Note: there is no strict definition for each family.

2:1 2:1 3:2 3:2 The 10th planet(s) and the end of Pluto

• Since the discovery of KBOs that Pluto was in a bad situation.

• November 14th, 2003, the “1st” 10th planet is announced: Sedna (2003VB12)

⇒ Now considered usually as a member of the Inner Oort Cloud.

• July 27th, 2005, the “2nd” 10th planet is announced: Haumea (2003EL61)

• July, 29th, 2005, the “3rd” 10th planet is announced: (2003UB313)

⇒ The American started a war of accusations against the Spanish team.

• First measurements indicated Eris was 50 km larger than Pluto, but soon after it was confirmed as being about 50 km smaller. Eris

Eris

Dysnomia Definition of Planet

(1) A planet[1] is a celestial body that (a) is in orbit around the , (b) has sufficient mass for its self- to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

(2) A “” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape[2], (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects[3], except satellites, orbiting the Sun shall be referred to collectively as “Small Bodies”.

Footnotes: [1] The eight planets are: , , Earth, , , , Uranus, and Neptune. [2] An IAU process will be established to assign borderline objects into either dwarf planet and other categories. [3] These currently include most of the Solar System , most Trans-Neptunian Objects (TNOs), comets, and other small bodies. Planet Nine • In 2008, Patryk Lykawka and Tadashi Mukai argue for the existence of a trans-Neptunian planet but they are not Americans… [ a = 100 – 175 AU, i = 20º– 40º, q > 80 AU, M = 0.3 – 0.7 M] • In 2014, and Scott S. Sheppard discuss the possible existence of a massive trans- Neptunian planet

• In 2016, and Mike E. Brown make a better argument for the existence of a massive trans-Neptunian planet, now nicknamed “planet nine”. P = 10 000 – 20 000 yr • The 8 m Subaru q = 200 AU telescope will be Q =1200 AU i = 30° used to attempt to detect it.

Credits: JPL, Batygin and Brown/Caltech, A. Cuadra/ How do we know? Giant Planets Migration

• Best way to explain the orbital structure (Malhotra 1993) • Different populations are probably superimposed (Gomes 2003, ..., Levison et al. 2009).

Credits: Levison & Morbidelli Implications

PAST MIGRATION AND MIXING Ejection

Contamination by comets? 5 AU 15 AU 30 AU 48 AU Mixing

Exogenous water?

PRESENTLY 5 AU Ejection 30 AU 48 AU NEOs Jupiter Neptune

Asteroid belt Shooting Kuiper belt Centaurs Comets So… we simulate scenarios • We study the orbital distributions and try to reproduce them through simulations.

Credits: Lykawka & Mukai (2008) So… we simulate scenarios • We study the orbital distributions and try to reproduce them through simulations.

Credits: Lykawka & Mukai (2008) Planet Nine How do we know? • Distant within the scattered disk population of the Kuiper belt exhibit an unexpected clustering in their respective arguments of perihelion. • The observed orbital alignment can be maintained by a distant eccentric planet with M>10 M⊕ , lying approximately in the same plane as those distant KBOS, but with perihelion 180 degrees away from the perihelia of the others.

M > 10 M⊕ R = 2 – 4 R⊕ P = 10 000 – 20 000 yr q = 200 AU a = 600 AU Q =1200 AU i = 30°

Credits: Nagualdesign - Own work, based on a video released by Caltech How do we know? • Distant orbits within the scattered disk population of the Kuiper belt exhibit an unexpected clustering in their respective arguments of perihelion. • The observed orbital alignment can be maintained by a distant eccentric planet with M>10 M⊕ , lying approximately in the same plane as those distant KBOS, but with perihelion 180 degrees away from the perihelia of the others.

M > 10 M⊕ R = 2 – 4 R⊕ P = 10 000 – 20 000 yr q = 200 AU a = 600 AU Q =1200 AU i = 30°

Credits: Nagualdesign - Own work, based on a video released by Caltech Oort Cloud Oort Cloud • In 1950, Oort argued for the existence of a far away “cloud”, around the solar system that should be the source of all comets (Öpik already had suggested it in 1932).

• Made by the large number of objects ejected by the giant planets

• The cloud should be ~10 000 and 100 000 AU (∼1 light-year).

• Maybe there is an “inner Oort cloud” slightly decoupled from the rest (Sedna and 2012VP113 are there).

• Nearby stars may push those objects so they become comets in the inner solar system.

• Number of comets ∼ 1012 Oort Cloud • In 1950, Oort argued for the existence of a far away “cloud”, around the solar system that should be the source of all comets (Öpik already had suggested it in 1932).

• Made by the large number of objects ejected by the giant planets

• The cloud should be ~10 000 and 100 000 AU (∼1 light-year).

• Maybe there is an “inner Oort cloud” slightly decoupled from the rest (Sedna and 2012VP113 are there).

• Nearby stars may push those objects so they become comets in the inner solar system.

• Number of comets ∼ 1012 Oort Cloud Thank you!