Asteroids with Satellites Database--Johnston's Archive

(2491) Tvashtri

compiled by Wm. Robert Johnston
last updated 23 September 2018

--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: main belt asteroid, Hungaria


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 1.8776230116 AU
orbital period P: 2.5728389319 yr
(= 939.7471681 d)
eccentricity e: 0.054172476
perihelion distance q: 1.775907524 AU
aphelion distance Q: 1.9793384988 AU
inclination i: 22.866198°
argument of perihelion ω: 357.912752°
ascending node Ω: 125.309799°
mean anomaly M: 30.552926°
perihelion passage TP: 2018 Jan 02.24437
Epoch: 2018 Mar 23
data arc: 1977-2018 (1394 obs.)
Earth MOID: 0.790968 AU
Jupiter Tisserand invariant TJ: 3.877


orbital data, secondary:
semimajor axis as: 7.5 km [*E]
separation/primary radius as/rp:4.7 [*D]
separation/Hill radius as/rH:0.016 [*D]
orbital period Ps: 1.113 ± 0.0002 d [W18b]
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 13.68 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 3.259 ± 0.084 km [**]
geometric albedo: 0.561 ± 0.207 [**]
color index U-B: 0.261 [JPL]
color index B-V: 0.756 [JPL]
taxonomic type: X (Tholen) [JPL]
mass m: ?
density ρ: (1.6 g/cm3) [*A]
Hill radius rH: 460 km [*E]

other data, primary:
diameter dp: 3.17 km [*D]
rotation period RPp: 4.0852 ± 0.0002 h [W18b]
amplitude in mag., rotational ΔM: 0.08 ± 0.01 [W18b]
amplitude in mag., mutual events ΔM:0.085 ±0.03 [W18b]
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: >0.76 km [*D]
diameter ratio ds/dp: >0.24 ± 0.02 [W18a]
component mag. difference ΔM: >3.1 [*D]
rotation period RPs: ?

-- (2491) Tvashtri --discovery and notes:

Primary discovered 1977 Feb 15 from Palomar Observatory, California, USA by W. Sebok. Alternate designation(s): 1977 CB . Permanent number assigned -.

Named 1993 Feb 06 for the mythological Indian god [MPC021606].

Companion discovered 2018 Mar 29 by B. D. Warner using lightcurve observations from CS3, Landers, California, USA. Announced 2018 May 04 [W18d].

--Links, more technical:

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--Links to ADS abstracts:


© 2018 by Wm. Robert Johnston.
Last modified 23 September 2018.
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