2015 TG387

2015 TG387
2015 TG387 has a long orbit in the lower right, the third known Sednoid with the highest aphelion of the three.
Discovery [1][2]
Discovered by
Discovery date October 13, 2015
Designations
MPC designation 2015 TG387
TNO · E-SDO · sednoid
Orbital characteristics [3]
Epoch 2018-Mar-23 (JD 2458200.5)
Uncertainty parameter 4
Observation arc 949 days (2.60 yr)
Aphelion 2037 AU
Perihelion 64.8 AU
1051 AU
Eccentricity 0.94
34080 years
359.4°
0.00002892°/day
Inclination 11.66°
300.90°
118.3°
Physical characteristics
Dimensions ~300 km (190 mi)[4]
5.3[3]

    2015 TG387 (nicknamed The Goblin for the letters TG and because its discovery was near Halloween),[5][6] is a trans-Neptunian object and sednoid in the outermost part of the Solar System.[7] It was first observed on October 13, 2015, by astronomers David J. Tholen, Scott S. Sheppard, and Chad Trujillo with the Subaru Telescope at Mauna Kea Observatories, and publicly announced on October 1, 2018.[2][8]

    Physical characteristics

    It is estimated to be 300 km (190 mi) in diameter.[4] Information is limited because it about as bright as one of Pluto's moons, 24th magnitude in the late 2010s when it was identified.[9] One of the problems is that its difficult to tell whether distant objects are reflecting more light because they are more reflective, or because they are bigger for example.[10]

    By observing the color and amount of light, and in combination with various methods and other known data about Trans-Neptunian objects its possible to develop a visualizations based on the predicted size, reflectivity, and spectrum:

    Examples of various Trans-Neptunian objects for comparison

    One of the objects known to also traverse far out into space, hundreds of AU from the Sun is Sedna, and is not very reflective and has a red color relative to icy bodies which tend to be brighter and whiter.[11] On way to understand TG387 is to compare observations in the infrared and visible light with a telescope using a spectrometer.[12]

    Orbit

    2015 TG387 is the third sednoid to be discovered, following 90377 Sedna and 2012 VP113.[4][13]

    Implications of orbit

    Along with the similar orbits of other distant trans-Neptunian objects, the orbit of 2015 TG387 suggests, but does not prove, the existence of a hypothetical Planet Nine in the outer Solar System.[4][8]

    As of 2018, the object is 80 AU from the Sun; about two-and-a-half times farther out than Pluto's current location.[6] As with Sedna, it would not have been found had it not been on the inner leg of its long orbit. This suggests that there may be many similar objects, most too distant to be detected by contemporary technological methods. Following the discovery of 2015 TG387, Sheppard et al. concluded that it implies a population of about 2 million inner Oort cloud objects larger than 40 km (25 mi), with a combined total mass of 1×1022 kg, which is several times the mass of the asteroid belt.[4]

    Visualizations

    References

    1. ↑ "2015 TG387". Minor Planet Center. Retrieved 10 October 2018.
    2. 1 2 "MPEC 2018-T05 : 2015 TG387". IAU Minor Planet Center. October 1, 2018. Retrieved October 2, 2018.
    3. 1 2 "JPL Small-Body Database Browser: (2015 TG387)" (2018-05-19 last obs.). Jet Propulsion Laboratory. Retrieved October 2, 2018.
    4. 1 2 3 4 5 Sheppard, Scott; Trujillo, Chadwick; Tholen, David; Kaib, Nathan (September 28, 2018). "A New High Perihelion Inner Oort Cloud Object". arXiv:1810.00013 [astro-ph.EP].
    5. ↑ Guarino, Ben (October 2, 2018). "New dwarf planet spotted at the very fringe of our solar system". The Washington Post. Retrieved October 3, 2018.
    6. 1 2 Chang, Kenneth (October 2, 2018). "A Goblin World That Points Toward Hidden Planet Nine in the Solar System". The New York Times. Retrieved October 2, 2018.
    7. ↑ Mortillaro, Nicole (October 2, 2018). "Discovery of new object supports theory of 'super-Earth' at edge of solar system". CBC News. Retrieved October 2, 2018.
    8. 1 2 Witze, Alexandra (October 1, 2018). "'Goblin' world found orbiting at the edges of the Solar System". Nature. doi:10.1038/d41586-018-06885-1. Retrieved October 2, 2018.
    9. ↑ "New object beyond Pluto hints at mysterious 'Planet X'". 2018-10-02. Retrieved 2018-10-11.
    10. ↑ "New object beyond Pluto hints at mysterious 'Planet X'". 2018-10-02. Retrieved 2018-10-11.
    11. ↑
    12. ↑
    13. ↑ "JPL Small-Body Database Search Engine: a > 150 (AU) and q > 50 (AU) and data-arc span > 365 (d)". JPL Solar System Dynamics. Retrieved October 2, 2018.

    See also

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