(26308) 1998 SM165 and S/2001 (26308) 1

Asteroids with Satellites Database--Johnston's Archive

(26308) 1998 SM165 and S/2001 (26308) 1

compiled by Wm. Robert Johnston
last updated 21 September 2014

--Orbital and physical data--

(See this page for definitions of quantities; source codes in brackets, see this link for full references; *A, *D, and *E indicate assumed, derived, and estimated values, respectively.)

dynamical type, primary: TNO, 1:2 resonance
orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 47.675 AU
orbital period P: 329.190 yr
(= 120236.8 d)
eccentricity e: 0.369454
perihelion distance q: 30.0614 AU
aphelion distance Q: 65.289 AU
inclination i: 13.50696°
argument of perihelion ω: 131.216°
ascending node Ω: 183.16624°
mean anomaly M: 43.221°
perihelion passage T_P: 1974 Nov 13
Epoch: 2014 May 23
data arc: 1982-2010 (83 obs.)
Earth MOID: 29.0631 AU
Jupiter Tisserand invariant T_J: 5.579

Neptune Tisserand invariant T_N: 2.91 [*D]

orbital data, secondary:

semimajor axis a_s: 11377 ± 8 km [G14a]
separation/primary radius a_s/r_p: 85 [*D]
separation/Hill radius a_s/r_H: 0.024 [*D]
orbital period P_s: 130.158 ± 0.005 d [G14a]
eccentricity e_s: 0.4727 ± 0.0007 [G14a]
inclination i_s: 81.57° ± 0.05° [G14a]
ascending node Ω_s: 47.09° ± 0.08° [G14a]
argument of pericenter ω_s: 114.9° ± 0.1° [G14a]
mean anomaly M: 280.5° ± 0.1° [G14a]
Epoch: 2003 Mar 01.5
normalized ang. mom. α_L: ?

other data, system (combined):

absolute mag. H: 5.8 [MPC]
6.38 [S08a]
slope parameter G: (0.15) [*A]
effective diameter d_E: 279.8 ± 29.7/28.6 km [S08b]
geometric albedo: 0.063 ± 0.015/0.012 [S08b]
color index U-B: 0.21 [J07a]
color index B-V: 1.02 [G14a]
color index V-R: 0.63 ± 0.02 [G14a]
color index B-R: 1.653 [H02a]
color index V-I: 1.3 ± 0.05 [D07c]
color index R-J: 1.71 [D07c]
color index V-J: 2.33 ± 0.06 [D07c]
color index J-H: 0.56 ± 0.04 [D07c]
color index V-H: 2.88 ± 0.08 [H02a]
taxonomic type: RR (G-mode) [B05b]
mass m: 6.87x10¹⁸ ± 1.8x10¹⁶ kg [G11a]
density ρ: 0.51 ± 0.29/0.14 g/cm³[S06b]
Hill radius r_H: 470000 km [*D]
other data, primary:

diameter d_p: 268 ± 28 km [*D]
color index V-I: 1.4 ± 0.04 [B08d]
rotation period RP_p: 8.4 ± 0.05 h [S06b]
amplitude in mag., rotational ΔM: 0.56 [T14a]
pole direction Β, λ: ? , ?

other data, secondary:

diameter d_s: 81 ± 14 km [*D]
diameter ratio d_s/d_p: 0.302 ± 0.042 [N08c]
component mag. difference ΔM: 2.69 [G14a]
color index V-I: 1.32± 0.05 [B08d]
rotation period RP_s: ?

-- (26308) 1998 SM165 and S/2001 (26308) 1 --discovery and notes:

Primary discovered 1998 Sep 16 from Kitt Peak Observatory, Arizona, USA by N. Danzl. Linked to prediscovery observations from 1982 Oct 12. Permanent number assigned 2001 Jul 05.

Companion discovered 2001 Dec 22 by M. E. Brown and C. A. Trujillo using Hubble Space Telescope observations from Hubble Space Telescope. Announced 2002 Jan 24 [B02b]. Provisional designation S/2001 (26308) 1.

--Links, more technical:

IAUC 7807.
1998 SM165--A large Kuiper Belt object with an irregular shape (abstract in EKO Newsletter).
Binary trans-Neptunian 1998 SM165.

--Links, less technical:

--Links to ADS abstracts:

Grundy, W. M., Stansberry, J. A., Noll, K. S., Stephens, D. C., Trilling, D. E., Kern, S. D., Spencer, J. R., Cruikshank, D. P., & Levison, H. F. 2007, Icarus The orbit, mass, size, albedo, and density of (65489) Ceto/Phorcys: A tidally-evolved binary Centaur
Jacobson, Seth & Margot, J. L. 2007, Bulletin of the American Astronomical Society Colors of TNO Binaries and Evidence for a Triple System from HST Observations
Spencer, John R., Stansberry, J. A., Grundy, W. M., & Noll, K. S. 2006, Bulletin of the American Astronomical Society A Low Density for Binary Kuiper Belt Object (26308) 1998 SM165
Spencer, John, Grundy, William, Noll, Keith, & Stansberry, John 2005, Spitzer Proposal Density and Albedo of the KBO Binary System 1999 SM165
Margot, J. L., Brown, M. E., Trujillo, C. A., & Sari, R. 2004, Bulletin of the American Astronomical Society HST observations of Kuiper Belt binaries
Brown, M. E. & Trujillo, C. A. 2002, International Astronomical Union Circular (26308) 1998 SM_165
Sheppard, Scott S. & Jewitt, David 2004, Astronomical Journal Extreme Kuiper Belt Object 2001 QG₂₉₈ and the Fraction of Contact Binaries
Romanishin, W., Tegler, S. C., Rettig, T. W., Consolmagno, G., & Botthof, B. 2001, Proceedings of the National Academy of Science 1998 SM₁₆₅: A large Kuiper belt object with an irregular shape
Delsanti, A. C., Boehnhardt, H., Barrera, L., Meech, K. J., Sekiguchi, T., & Hainaut, O. R. 2001, Astronomy and Astrophysics BVRI Photometry of 27 Kuiper Belt Objects with ESO/Very Large Telescope
Romanishin, W., Tegler, S. C., Rettig, T. W., Consolmagno, G., & Botthof, B. 2001, Bulletin of the American Astronomical Society (26308) 1998 SM165: A Large Kuiper Belt Object with an Irregular Shape
McMillan, R. S., Larsen, J. A., May, B., Maggs J., D., Danzl, N., & Marsden, B. G. 1999, Minor Planet Electronic Circ., 1999-U17 (1999). 1998 SM165
Danzl, N. & Marsden, B. G. 1999, Minor Planet Electronic Circ., 1999-M31 (1999). 1998 SM165

© 2002-2012, 2014 by Wm. Robert Johnston.
Last modified 21 September 2014.
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