Английская Википедия:474640 Alicanto

Содержание

Текст

Текст

Текст

Текст

Текст

Текст

Текст

Текст

Текст

474640 Alicanto, provisionally designated Шаблон:Mp, is a detached extreme trans-Neptunian object. It was discovered on 6 November 2004, by American astronomer Andrew C. Becker at Cerro Tololo Inter-American Observatory in Chile. It never gets closer than 47 AU from the Sun (near the outer edge of the main Kuiper belt) and averages more than 300 AU from the Sun. Its large eccentricity strongly suggests that it was gravitationally scattered onto its current orbit. Because it is, like all detached objects, outside the current gravitational influence of Neptune, how it came to have this orbit cannot yet be explained. It was named after Alicanto, a nocturnal bird in Chilean mythology.

Discovery and orbit

Файл:Planet nine-etnos now.png

Alicanto's orbit in red with hypothetical Planet Nine

Alicanto was discovered by American astronomer A. C. Becker with the ESSENCE supernova survey on 6 November 2004 observing with the 4-meter Blanco Telescope from Cerro Tololo Inter-American Observatory. Precovery images have been found back to September 26, 2000. Alicanto was observed by the Hubble Space Telescope in November 2008, and found not to have any detectable companions. It reached perihelion (closest approach to the Sun) in 2009 and is currently 47.7 AU from the Sun. It will be in the constellation of Cetus until 2019. It comes to opposition at the start of November.

With an perihelion greater than 40 AU, Alicanto is an extreme trans-Neptunian object which are practically detached from Neptune's gravitational influence. Its orbit is characterized by high eccentricity (0.850), moderate inclination (25.58°) and a semi-major axis of 316 AU. Upon discovery, it was classified as a trans-Neptunian object. Its orbit is well determined; as of 11 January 2017 its orbital solution is based on 34 observations spanning a data-arc of 5821 days. AlicantoШаблон:'s orbit is similar to that of Шаблон:Mpl, indicating that they may have both been thrown onto the orbit by the same body, or that they may have been the same object (single or binary) at one point.

Naming

On 14 May 2021, the object was named by the Working Group for Small Bodies Nomenclature (WGSBN) after Alicanto from Chilean mythology. The nocturnal bird of the Atacama Desert has wings that shine at night with beautiful, metallic colors.

Physical characteristics

Alicanto has an absolute magnitude of 6.5 which gives a characteristic diameter of 130 to 300 km for an assumed albedo in the range 0.25–0.05.

Michael Brown's website lists it as a possible dwarf planet with a diameter of Шаблон:Convert based on an assumed albedo of 0.04. The albedo is expected to be low because the object has a blue (neutral) color. However, if the albedo is higher, the object could easily be half that size.

AlicantoШаблон:'s visible spectrum is very different from that of 90377 Sedna. The value of its spectral slope suggests that the surface of this object can have pure methane ices (like in the case of Pluto) and highly processed carbons, including some amorphous silicates. Its spectral slope is similar to that of Шаблон:Mp.

Relevance to the Planet Nine Hypothesis

This minor planet is one of a number of objects discovered in the Solar System to have a semi-major axis > 150 AU, a perihelion beyond Neptune, and an argument of perihelion of 340 ± 55°. Of these, only eight, including Alicanto, have perihelia beyond Neptune's current influence.

Comparison

Файл:Distant object orbits + Planet Nine.png

The orbits of Шаблон:Dp, Шаблон:Mpl, Leleākūhonua, and other very distant objects along with the predicted orbit of Planet Nine. The three sednoids (pink) along with the red-colored extreme trans-Neptunian object (eTNO) orbits are suspected to be aligned with the hypothetical Planet Nine while the blue-colored eTNO orbits are anti-aligned. The highly elongated orbits colored brown include centaurs and damocloids with large aphelion distances over 200 AU.

See also

• List of Solar System objects by greatest aphelion

External links

• New data about two distant asteroids give a clue to the possible "Planet Nine"
• Dos asteroides lejanos apoyan la hipótesis del Planeta Nueve
• Шаблон:AstDys
• Шаблон:JPL small body