Bibcode
Oszkiewicz, D.; Kryszczyńska, Agnieszka; Kankiewicz, Paweł; Moskovitz, Nicholas A.; Skiff, Brian A.; Leith, Thomas B.; Ďurech, Josef; Włodarczyk, Ireneusz; Marciniak, Anna; Geier, S.; Fedorets, Grigori; Troianskyi, Volodymyr; Föhring, Dóra
Bibliographical reference
Astronomy and Astrophysics, Volume 623, id.A170, 7 pp.
Advertised on:
3
2019
Journal
Citations
7
Refereed citations
7
Description
Context. Asteroid (2579) Spartacus is a small V-type object located in
the inner main belt. This object shows spectral characteristics unusual
for typical Vestoids, which may indicate an origin deeper than average
within Vesta or an origin from an altogether different parent body. Aims: Our main goal is to study the origin of Spartacus. We derive
the spin of Spartacus and a convex shape model of Spartacus in order to
increase the knowledge of the body's physical properties. The rotational
parameters are then used to investigate dynamical evolution of the
object as well as to distinguish regions sampled by spectral
observations to determine whether its surface displays heterogeneity.
Methods: We collected lightcurves available from the literature
(oppositions of 2009, 2012) and obtained additional photometric
observations at various telescopes in 2016, 2017, and 2018. We used the
lightcurve inversion method to derive a spin and convex shape model. We
have collected spectral observations over two rotational periods of
Spartacus and determined its spectral parameters using the modified
Gaussian model (MGM). We then dynamically integrated the orbital
elements of Spartacus, taking into account existing information,
including its thermal properties, size and the derived spin axis
orientation. Results: We find two models for (2579) Spartacus:
(a) λ = 312° ± 5°, β = -57° ±
5° and (b) λ = 113° ± 5°, β = -60°
± 5° both retrograde. We find that the drift direction for
Spartacus is consistent with separation from Vesta, and after a backward
integration of 1 Gyr the asteroid reaches the boundary of the family. We
did not observe spectral variations with rotation, thus the body most
likely has a homogeneous surface. Additionally, new spectral analysis
indicates that the 1.0 and 2.0 μm band centers are within ranges that
are typical for Vestoids while the area ratio of these bands is about
half that of typical Vestoids. Conclusions: The asteroid (2579)
Spartacus is in retrograde rotation and has a drift direction consistent
with an origin from Vesta. The revised spectral band centers are within
ranges typical for Vestoids, while band area ratio (BAR) is unusually
low compared to that of other V-types. The dynamical model shows that
the asteroid could have migrated to its current location from the edges
of the Vesta family within 1 Gyr, but an origin from an earlier impact
on Vesta could also be plausible.