Techniques d'observation spectroscopique d'astéroïdes

100 CHAPTER 6. SPECTRAL PROPERTIES OF NEAR-EARTH ASTEROIDS
(16960) 1998 QS52
Taxonomic classification for (16960) 1998 QS52
tel-00785991, version 1 - 7 Feb 2013
Relative Reflectance
(a)
Relative Reflectance
(c)
1.1
1.05
1
0.95
0.9
0.85
0.8
0.75
0.7
0.14
0.13
0.12
0.11
0.1
0.09
0.08
V
NIR
0.5 1 1.5 2 2.5
Wavelength [um]
Asteroid
Relab sample
0.5 1 1.5 2 2.5
Wavelength [um]
Relative Reflectance
(b)
Relative Reflectance
(d)
1.15
1.1
1.05
1
0.95
0.9
0.85
0.8
0.75
Spectrum
Sr
0.7
Sq
0.65
Q
0.5 1 1.5 2 2.5
Wavelength [um]
0.155
0.15
0.145
0.14
0.135
0.13
0.125
0.12
0.115
0.11
0.105
Asteroid
Relab sample
0.5 1 1.5 2 2.5
Wavelength [um]
Figure 6.3: a) The visible [Binzel et al., 2004b] and the NIR spectra of (16960) 1998 QS52; b) a polynomial fit
of the V+NIR spectrum of (16960) 1998 QS52 compared with the theoretical spectra of Sr, Sq and Q types; c)
the reflectance spectrum of (16960) 1998 QS52 and the closest fit resulting from spectral comparison - the L4
ordinary chondrite Saratov; d) the de-reddened spectrum of (16960) 1998 QS52 and the closest fit resulting from
meteorite comparison - the LL4 ordinary chondrite Hamlet.
6.2.3 (16960) 1998 QS52
With an absolute magnitude H = 14.20, this asteroid has an estimated diameter of 4.3 km
[Binzel et al., 2002]. It is characterized by a synodic period of 2.900±0.001 hrs [Warner,
2009]. It has an Apollo orbit type and ∆V = 6.5 km/s, which makes it an accessible target
for a spacecraft mission. (16960) 1998 QS52 is a PHA object type with 0.01408 AU MOID
computed at epoch 55600.0 MJD (NeoDys 1 ).
On the basis of a visible spectrum acquired with the MDM 2.4 m telescope in 15 October
1998, Binzel et al. [2004b] classified this asteroid as Sq type. The spectrum of the visible
region has a small negative slope of -0.0205 µm −1 . The following analysis was made on the
combined V+NIR spectrum (Fig. 6.3a).
Both methods for taxonomic classification (M4AST and MIT-SMASS online tool) of clas-
1 htt p ://newton.dm.unipi.it/neodys/