The two rings of (50000) Quaoar | Astronomy & Astrophysics (A&A)

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This article has an erratum: [https://doi.org/10.1051/0004-6361/202346365e]

Table 2.

Retrieved parameters of Quaoar’s body and its rings.

Quaoar’s limb fitting

Apparent semi-major axis	a′ = 579.5 ± 4.0 km
Apparent oblateness	ϵ′ = 0.12 ± 0.01
Position angle	P = 345.2 ± 1.2 deg
Ephemeris offset	f_c = −24.7 ± 2.0 km
	g_c = −13.9 ± 2.1 km
R_equiv	543 ± 2 km
χ² per degree of freedom	0.986

Quaoar’s geocentric	mas
position (ICRS)	mas

Q1R’s preferred pole
position (ICRS) ⁽¹⁾	δ_P = +53° 27′±18′

Q1R’s geometry

Radius	4, 057 ± 6 km
Opening angle	B = −20.0 ± 0.3 deg
Position angle	P = 350.2 ± 0.2 deg
χ² per degree of freedom	1.633

Q2R’s geometry ⁽²⁾

Radius	2520 ± 20 km

Notes. Quaoar’s limb, Quaoar’s geocentric position, and Q1R’s geometry are given at epoch August 9th, 2022, 06:34:03.560 UTC. The fits use the star position and the NIMAv16 ephemeris for Quaoar (Table 1).

⁽¹⁾

The preferred solution is co-planar with Quaoar’s equatorial plane and Weywot’s orbit within 5 ± 7 deg. The complementary position α_P = 10^h00^m ± 05^m and δ_P = +79° 21′±08′, is not considered here as it provides a less satisfactory fit to the Q1R detections and yields an inclination of 45 deg with respect to Weywot’s orbit, see Sect. 4.2

⁽²⁾

Assuming a circular ring co-planar with Q1R. The error bar for the Q2R ring radius may be underestimated since we only have two effective detections, and several parameters were assumed.

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