The MITIRTF Joint Campaign For NEO Spectral Reconnaissance

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The MIT-IRTF Joint Campaign For NEO Spectral
Reconnaissance

• R.P. Binzel (MIT), A.T. Tokunaga (Univ. of Hawaii)

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Objectives
Near-Earth objects (NEOs) are the most accessible
objects in the solar system for spacecraft
missions, with many having sample return (or
human exploration) propulsion requirements
substantially lower than the Moon. We are
undertaking a joint MIT-UH reconnaissance of
specific subsets of the NEO population with
immediate dissemination of data open to the
entire community. Our specific science goals
are

• Measure the spectral characteristics of NEOs
  having propulsion requirements that mission planning can be driven by scientific
  criteria (basic knowledge of the target
  properties) rather than by simple dynamical
  (minimum DV) requirements.
• Characterize the properties of objects in
  comet-like orbits for understanding
  asteroid-comet connections-- identification of
  extinct comet candidates will constrain the comet
  source fraction for NEOs.
• Characterize the potentially hazardous asteroid
  subgroup and to specifically compare with the
  broader NEO population to understand better
  meteorite sources.

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Obtaining data, dissemination, and some results

• Data is obtained remotely from MIT using
  undergraduate and graduate students. This
  provides education, training, and research in an
  effective manner.
• Reduced data are archived on the web and are
  accessible to anyone (http//smass.mit.edu/minus.
  html). A link to this web site is on the IRTF
  home page as well.
• In the following slides we show some recent
  results.

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Joint Program Operations via Remote Observing
NASA IRTF
MIT Campus
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Potentially Hazardous Asteroids
2004 MN4
Spectrum of Earth-approacher 2004 MN4 reveals an
S-type to Q-type class, allowing estimates for
its albedo and a size 300 m.
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Spectral and Albedo Results
Low albedo NEOs in the vicinity of 1 AU become
warm enough to emit measurable thermal flux
shortward of 2.5 mm, as seen for 2001 ME1.
Thermal modeling by Rivkin et al. 2005 (solid
line) fits an albedo of 3.
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Comet Candidates
Spectrum of Geminid meteor stream parent body
3200 Phaethon and the spectrum of the low
activity comet 2004 TU12. The coma density may
have been low enough to allow this spectrum to
represent the nucleus. The spectral upturn
beyond 2 mm is likely due to thermal emission,
from which the albedo may be constrained (Rivkin
et al. 2005).
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Meteorite Links
Comparison of 69230 Hermes (points) to L6
chondrite meteorites (red line). The blue line
represents a linear mixture of 60 L6 material
and 40 neutral material with the same albedo as
the meteorite, which lowers the absorption band
contrast. Such an effect could also be due to
particle size effects rather than mixture with
spectrally neutral material.