Kalpana Kalpana (Editor)

(386723) 2009 YE7

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Discovered by
David Rabinowitz

MPC designation
2009 YE7

Observation arc
2273 days (6.22 yr)

Absolute magnitude

Asteroid family
Haumea family

Discovery date
17 December 2009

Alternative names

17 December 2009

David L. Rabinowitz

(386723) 2009 YE7

Minor planet category
TNO Cubewano Haumea family

Minor planet categories
Trans-Neptunian object, Classical Kuiper belt object

(19308) 1996 TO66, 2008 ST291, S/2000 (1998 WW31) 1, (84922) 2003 VS2, (119951) 2002 KX14

(386723) 2009 YE7, also written as (386723) 2009 YE7, is a trans-Neptunian object (TNO) discovered by David Rabinowitz on December 17, 2009 at the La Silla Observatory in Chile.



(386723) 2009 YE7 is a classical Kuiper belt object: Its orbit is not controlled by an orbital resonance with Neptune, similar to (15760) 1992 QB1, but with a much greater orbital eccentricity and inclination. It completes one orbit around the Sun in just over 247 Earth years, at an average distance of about 44 AU. It came to perihelion around 1868, and to aphelion in 2015. It is currently about 50.7 AU from the Sun, and will again return to perihelion around 2163.


(386723) 2009 YE7 has been observed 70 times, with precovery images dating back to 2006, and has an orbital quality code of 4.

Absolute magnitude

The size of an object can be ascertained once its absolute magnitude (H) and its albedo (the proportion of light it reflects) are known. When (386723) 2009 YE7 was first discovered, it was believed to have an absolute magnitude (H) of 2.8, which would have made it the first bright KBO found from the southern hemisphere.(386723) 2009 YE7 has an absolute magnitude (H) of 4.25. Since (386723) 2009 YE7 has an absolute magnitude dimmer than (H=1), it will not be overseen by two naming committees and will not automatically be listed as a dwarf planet by the International Astronomical Union (IAU). This value would've made it the eighth-intrinsically-brightest known trans-Neptunian object, but it was later found to be much dimmer. It has an absolute magnitude (H) of 4.25., which would make it a good dwarf-planet candidate when using an albedo of 0.09. However, it is probably much smaller than previously thought, since it is also suspected of being a highly reflective icy member of the Haumea family.

(386723) 2009 YE7 has been found to be a member of the Haumea family fragment due to its Haumea-like orbit and the detection of water ice on its surface. This means (386723) 2009 YE7 could have an albedo of up to 0.7, resulting in a small size close to 200 kilometres (120 mi). However, its actual albedo is unknown; if its albedo turns out to be lower, it would result in a larger size estimate.

Any icy body with a diameter equal to or greater than 400 kilometres (250 mi) is expected to be spherical. Many small icy low-density moons, such as Mimas and Miranda are known to be spherical.


(386723) 2009 YE7 Wikipedia