Data Set Information
DATA_SET_NAME FORNASIER SPECTRA OF M ASTEROIDS V1.0
DATA_SET_ID EAR-A-I1092-2-MSPECTRA-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : This data set includes reduced composite visible and near-infrared spectra of 30 M-type asteroids that have been published in Fornasier et al. (2010). The spectra were obtained over the years 2004-2008 at three different telescopes, and used to produce a single composite reduced visible-near-IR spectrum for each asteroid. For one asteroid, 125 Liberatrix, three composite spectra were produced for different times in the same night. The remaining 29 asteroids are represented by a single composite spectrum each. The 75 individual spectra from the NTT/EMMI, NTT/SOFI, TNG/NICS, and TNG/Dolores instruments, which were combined to make the composite spectra, are also included here. The composite spectra are in the subdirectory 'compspectra' and the individual spectra are in the subdirectory 'indivspectra' under the data directory. The individual spectra from the SPeX instrument at IRTF are not included in this data set as they are available in another PDS data set, the IRTF NEAR-IR Spectroscopy of Asteroids, EAR-A-I0046-4-IRTFSPEC-V2.0. At the TNG telescope, the visible spectra were obtained with Dolores (Device Optimized for Low Resolution) equipped with the low resolution red grism (LR-R) covering the 0.51-0.95 micron range with a spectral dispersion of 2.9 A/pixel. Most of the objects were also observed with the low resolution blue grism (LR-B, dispersion of 1.7 A/pixel, 0.4-0.7 micron range). The red and blue spectra in the visible range were separately reduced and then combined to obtain spectral coverage from 0.40 to 0.95 microns. The near-infrared spectra at the TNG were obtained with the NICS (Near Infrared Camera and Spectrometer) equipped with an Amici prism disperser. The equipment covers a spectral range of 0.85-2.40 microns with a spectral resolution of about 35 (Baffa et al. 2001). Both the visible and near infrared observations were made with a 1.5 arcsecond slit width, oriented along the parallactic angle to minimize the effect of atmospheric differential refraction. At the NTT telescope, visible spectra were obtained with the EMMI instrument in RILD mode, using Grism #1 to cover the wavelength range 4100-9600 Angstroms with a dispersion of 3.1 A/pixel at the first order. (An order-separation filter was not used for these observations, because tests with and without the order-separation filter showed that the second-order contribution was negligible.) The near-infrared spectra taken at the NTT telescope were taken with the instrument SOFI (Son OF Isaac) in the low resolution mode (Moorewood et al. 1998). The blue grism, with 0.95-1.64 micron range and dispersion of 6.96 A/pixel, and the red grism with 1.53-2.52 micron range and dispersion of 10.22 A/pixel, were used each with an order sorting filter. The blue and red grisms with their filters are designated as GBF and GRF respectively. The NTT observations were made with a 2 arsecond slit, always oriented along the parallactic angle. At the IRTF, the SpeX instrument was used, with wavelength range of 0.82 to 2.49 microns (Rayner et al. 2004). Spectra were recorded with a 0.8 x 15 arsecond slit oriented in the north-south direction. A dichroic lens reducing the signal below 0.8 microns was used for all observations. Objects were consistently observed near the meridian to minimize the airmass, but total integration time varied from 6 to 30 minutes depending on the strength of the signal relative to sky lines. The composite spectra are all normalized to 1.0 at a wavelength of 0.55 microns. The individual spectra are normalized as follows for the different instruments; NTT/SOFI gb: 1.25 micron NTT/SOFI gr: 2.15 micron NTT/EMMI: 0.55 micron TNG/Dolores (lrr, lrb and mrb): 0.60 micron TNG/NICS: 1.25 micron The thirty-two composite spectra included in this data set are plotted in Figures 1 through 5 in Fornasier et al (2010). The spectra of 132 Aertha, 125 Liberatrix, 201 Penelope, 382 Dodona, 418 Alemannia, and 558 Carmen cover the visible range only, while the remaining asteroids' spectra combine data to cover the visible and near infrared. The plots from the paper are included in a pdf file (spectraplots.pdf) in the document directory to provide easy browsing of the spectra. Observational circumstances for each observation are given in the file obscirc.tab, and reproduce the information in Table 1 of the paper. Each composite spectrum combines all the observations shown for the asteroid in obscirc.tab, except for 785 Zwetana, which used only the TNG observations, omitting the NTT visible observation. (Two errors in Table 1 have been corrected in obscirc.tab: The SOFI observations of 369 Aeria and 498 Tokio are shown in the paper as being both GBF observations, whereas in fact they were one each of GBF and GRF.) For details of the data acquisition and reduction, see Fornasier et al. (2010). References : Baffa, C. and 16 colleagues, NICS: The TNG near-infrared camera spectrometer, Astronomy and Astrophysics, 378, 722-728, 2001. Fornasier, S., B.E. Clark, E. Dotto, A. Migliorini, M. Ockert-Bell, and M.A. Barucci, Spectroscopic survey of M-type asteroids, Icarus 210, 655-673, doi:10.1016/j.icarus.2010.07.001, 2010. Moorewood, A., J.-G. Cuby, and C. Lidman, SOFI sees first light at the NNT, Messenger 91, 9-13, 1998. Rayner, J.T., P. M. Onaka, M. C. Cushing and W. D. Vacca, Four Years of Good SpeX, in Ground-based Instrumentation for Astronomy, A. F. M. Moorwood and M. Iye, Eds., Proceedings of the SPIE, vol. 5492, pp. 1498-1509, 2004.
DATA_SET_RELEASE_DATE 2011-05-31T00:00:00.000Z
START_TIME 2004-02-29T12:00:00.000Z
STOP_TIME 2008-12-22T12:00:00.000Z
MISSION_NAME SUPPORT ARCHIVES
MISSION_START_DATE 2004-03-22T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME 110 LYDIA
125 LIBERATRIX
129 ANTIGONE
132 AETHRA
135 HERTHA
16 PSYCHE
161 ATHOR
201 PENELOPE
216 KLEOPATRA
22 KALLIOPE
224 OCEANA
250 BETTINA
325 HEIDELBERGA
338 BUDROSA
347 PARIANA
369 AERIA
382 DODONA
418 ALEMANNIA
441 BATHILDE
498 TOKIO
516 AMHERSTIA
55 PANDORA
558 CARMEN
69 HESPERIA
755 QUINTILLA
785 ZWETANA
849 ARA
860 URSINA
872 HOLDA
97 KLOTHO
ASTEROID
TARGET_TYPE ASTEROID
INSTRUMENT_HOST_ID OBS056T9
OBS270T7
OBS376T3
INSTRUMENT_NAME SPEX
ESO MULTI-MODE INSTRUMENT: RILD MODE
DOLORES (DEVICE OPTIMIZED FOR LOW RESOLUTION)
NEAR INFRARED CAMERA SPECTROMETER (NICS)
SOFI (SON OF ISAAC)
INSTRUMENT_ID I0046
I0373
I1092
I1093
I1094
INSTRUMENT_TYPE SPECTROMETER
IMAGING SPECTROMETER
NODE_NAME Small Bodies
ARCHIVE_STATUS LOCALLY_ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : Fringing associated with the Dolores chip: The Dolores chip, like most LORAL CCDs, is affected by moderate to strong fringing at red wavelengths. Despite care in the the reduction process, some of the asteroid spectra taken with Dolores show residual fringing that impedes identification of absorption bands in the 0.9 micron region. Calculation of the uncertainties: Uncertainties were estimated from the signal to noise ratio of the observed asteroid (including the CCD quantum efficiency) plus the errors associate to solar analog stars used to get the relative reflectivity. Several solar analogs stars were observed each night and those observed at similar conditions were ratioed with each other. The deviation enabled estimation of the errors associated with the use of a given solar analogue. The errors are between 1.3-1.5 percent below 0.45 micron, between 1-1.3 percent in the 0.45-0.90 micron region, and between 1.5-3.0 percent in the infrared region, with higher uncertainties associated with the low transmission atmospheric windows. For additional information about the confidence level of these data, see Fornasier et al. (2010).
CITATION_DESCRIPTION Fornasier, S., Clark, B.E., Migliorini, A., and Ockert-Bell, M., Fornasier Spectra of M Asteroids V1.0. EAR-A-I1092-2-MSPECTRA-V1.0. NASA Planetary Data System, 2011.
ABSTRACT_TEXT This data set contains reduced composite visual and near-infrared spectra of thirty M-type asteroids, observed over the years 2004-2008 and presented in Fornasier et al. (2010). The spectra were taken with the Dolores and NICS instruments at the Telescopio Nationale Galileo (TNG) in La Palma, with the EMMI and SOFI instruments at the ESO New Technology Telescope (NTT) in Chile, and with the SPeX instrument at the Infrared Telescope Facility (IRTF) in Hawaii. The individual spectra from the various instruments used to produce the composite spectra are also included.
PRODUCER_FULL_NAME CAROL NEESE
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