The origin of (90) Antiope from component-resolved near-infrared spectroscopy

F. Marchis, J. E. Enriquez, J. P. Emery, J. Berthier, P. Descamps, F. Vachier

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The origin of the similarly-sized binary Asteroid (90) Antiope remains an unsolved puzzle. To constrain the origin of this unique double system, we recorded individual spectra of the components using SPIFFI, a near-infrared integral field spectrograph fed by SINFONI, an adaptive optics module available on VLT-UT4. Using our previously published orbital model, we requested telescope time when the separation of the components of (90) Antiope was larger than 0.087″, to minimize the contamination between components, during the February 2009 opposition. Several multi-spectral data-cubes in J band (SNR = 40) and H. +. K band (SNR = 100) were recorded in three epochs and revealed the two components of (90) Antiope. After developing a specific photometric extraction method and running an error analysis by Monte-Carlo simulations, we successfully extracted reliable spectra of both components from 1.1 to 2.4μm taken on the night of February 21, 2009. These spectra do not display any significant absorption features due to mafic mineral, ices, or organics, and their slopes are in agreement with both components being C- or Cb-type asteroids. Their constant flux ratio indicates that both components' surface reflectances are quite similar, with a 1-sigma variation of 7%. By comparison with 2MASS J, H, K color distribution of observed Themis family members, we conclude that both bodies were most likely formed at the same time and from the same material. The similarly-sized system could indeed be the result of the breakup of a rubble-pile proto-Antiope into two equal-sized bodies, but other scenarios of formation implying a common origin should also be considered.

Original languageEnglish (US)
Pages (from-to)252-264
Number of pages13
Issue number1
StatePublished - May 2011
Externally publishedYes


  • Adaptive optics
  • Asteroids, Surfaces
  • Satellites of asteroids
  • Spectroscopy

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'The origin of (90) Antiope from component-resolved near-infrared spectroscopy'. Together they form a unique fingerprint.

Cite this