Data Set Information
DATA_SET_NAME FIEBER-BEYER IRTF MAINBELT ASTEROID SPECTRA V3.0
DATA_SET_ID EAR-A-I0046-3-FBIRTFSPEC-V3.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : Near-infrared spectral observations of 52 asteroids located at ~2.5 AU were obtained using the NASA IRTF SpeX instrument covering the 0.7 to 2.5 micron spectral interval. The reflectance spectra were obtained using the low-medium resolution spectrograph SpeX (RAYNER et al. 2003). SpeX was used in the low- resolution spectrographic mode (asteroid mode) for two reasons: 1) its ability to obtain spectra with a fairly high signal to noise ratio (SNR) even for weak signal received from asteroids and 2) its ability to resolve broad absorption features produced by mafic silicate minerals. The data in each asteroid spectral file contains three columns: wavelength (in microns), relative reflectance, and uncertainty in relative reflectance. The label also includes keywords indicating the target name (asteroid name and number), target type (asteroid), UT start and end dates of the first and last asteroid observations used in creating the final reduced, calibrated average spectrum, number of exposures used in creating the final reduced, average calibrated spectrum, net integration time, apparent V-mag, phase angle, geocentric distance, heliocentric distance of the asteroid at the time of the respective asteroid observations. The solar analog star used for each asteroid's spectral calibration is listed. The listed airmass is the airmass at the start of the first observation of the respective asteroid. Observations : During an observing run the telescope nodded between the A beam and the B beam(For SpeX, the telescope nod distance is 7.5 arcsec, positioning the spectrum image at 1/4 and 3/4 distance along the 15 arcsec slit), so images were taken in spectral image pairs of the target asteroid, local standard star, solar-analog stars, and calibration flat-field and argon arc-lamp images. To produce high quality NIR asteroid reflectance spectra, we empirically derived the atmospheric extinction coefficients at each wavelength for each night or portion of the night. To model the atmospheric extinction over Mauna Kea, the slopes/intercepts of the relationship between the log of the flux (apparent magnitude) vs. airmass were calculated for each local standard star observation series. The observational procedure to produce the slopes and intercepts required pairing each asteroid with a nearby solar type star that experienced the same atmospheric conditions (temporally and spatially). The local standard star and the asteroid observations were temporally and spatially related as well and were interspersed within the same air mass range (typically observed at airmasses less than 1.5). The IRTF SpeX instrument uses an argon lamp as its wavelength reference. Each night several argon arc spectra were obtained for wavelength calibration. Data Reduction : The data were reduced and analyzed at the University of North Dakota. The obtained raw spectra were in the form of Flexible Image Transport System (FITS) images. Two software packages were used to process the data: 1) the Unix-based Image Reduction and Analysis Facility (IRAF) from the National Optical Astronomy Observatories (NOAO), and 2) SpecPR a Windows-based program for reduction and analysis of near-infrared spectra stored in one-dimensional arrays (CLARK 1980; GAFFEY 2003). The extraction of spectra, background sky subtraction, summing the image rows encompassing the object flux, conversion to text files, and determination of wavelength calibration were done using IRAF. Spectral processing using SpecPR involved many important phases to achieve a final, reduced spectrum. Important operations included: 1) calculation of starpacks from standard stars, 2) channel shifting to account for instrumental flexure, 3) averaging routines, and 4) data analysis (division of individual asteroid spectra by the relevant starpack and solar analog/standard star, polynomial fits, and determination of band positions/centers/band area ratios). Detailed descriptions of this method can be found in (FIEBER-BEYER 2010; REDDY 2009; ABELL 2003; HARDERSEN 2003; GAFFEY 2003; GAFFEY ET AL. 2002). A brief overview of how SpecPR creates a final, reduced averaged nightly spectrum is as follows: each asteroid observation was divided at each wavelength by the star flux calculated from the selected starpack, which not only encompassed the asteroid in airmass, but also most effectively removed the 1.4 micron and 1.9 micron telluric water vapor absorption features from the spectrum. Specifically, atmospheric extinction coefficients (starpacks) are computed from two or more sets of standard star observations. Extinction coefficients are determined for all sets of standard star observations (whole night starpacks), for portions of each night, and for individual sequential sets of standard star observations. Starpacks are used to calculate the standard star flux as a function of wavelength at the same airmass as each asteroid observation. The individual asteroid flux spectra were divided by the computed standard star flux ratio. The asteroid/star spectrum which most accurately canceled the atmospheric water vapor absorptions is selected as the best reduction. Since the stars and the asteroids were measured with the same instrument, the wavelength-dependent instrumental response was cancelled out when the asteroid flux measurements were ratioed to the extinction-corrected standard star flux measurements. The solar analog star data were reduced by the same method and used to correct for any non-solar behavior of the local standard stars producing a reflectance spectrum. Individual best spectra were reduced by this technique then after inspection for spurious sets - averaged together to produce a nightly average spectrum for each asteroid. The best reductions were normalized across a spectral interval to avoid the noise that may be associated with any individual point in the spectrum. The normalization value was the average of the values in SpeX channels 380 to 410. (1.5 to 1.7 microns). This interval was chosen because it is essentially unaffected by either the 1.4 or 1.9 micron atmospheric water vapor absorptions, or by the mafic silicate absorption feature centered in the 1.8 to 2.5 micron interval, common in asteroid spectra. A total of 52 asteroids were included in the survey. The data have been published in FIEBER-BEYER 2010; FIEBER-BEYER AND GAFFEY 2011; FIEBER-BEYER ET AL. 2011a; FIEBER-BEYER ET AL. 2011b; FIEBER-BEYER ET AL. 2012; FIEBER-BEYER AND GAFFEY 2014; FIEBER-BEYER AND GAFFEY 2015. This is an ongoing survey and data will be added to this archive yearly as they are published. Parameter table and Thumbnail Plots : A table listing all the spectra with their observational parameters, called spectraparameters.tab, is provided in the data directory. Thumbnail plots for browsing the spectra are available in the document directory. The file thumbnailcumulative.pdf is cumulative with the asteroid spectra arranged in ascending numerical order. Modification History : New to V3.0 are an additional 13 unpublished asteroid spectra obtained spanning the years 2012 through 2014. The total number of asteroids has been amended in the data set description to reflect a total of 52. Two publications, one for 2014 and one for 2015, have been added within the data set description to reflect where the data can be found in literature for the asteroids published during these years. The thumbnail.pdf file contains 52 asteroid spectra from the years 2000 through 2014. References : Abell, P.A., Near-IR reflectance spectroscopy of main belt and near-Earth objects: A study of their composition, meteorite affinities and source regions. Ph.D. dissertation. Rensselaer Polytechnic Institute, Troy,NY, USA, 2003. Clark, R.N., A large-scale interactive one-dimensional array processing system. Publ. Astron. Soc. Pac. 92, 221-224, 1980. Fieber-Beyer, S.K., Mineralogical characterization of asteroids in/near the 3:1 Kirkwood Gap, Ph.D. Dissertation, University of North Dakota, Grand Forks, 203 pp, 2010. Fieber-Beyer, S.K., and M.J. Gaffey, Near-infrared Spectroscopy of 3:1 Kirkwood Gap Asteroids (3760) Poutanen and (974) Lioba. Icarus, 214, 645-651, doi:10.1016/j.icarus.2011.06.014, 2011. Fieber-Beyer, S.K., M.J. Gaffey, and P.A. Abell, Mineralogical characterization of Near Earth Asteroid (1036) Ganymed, Icarus, 212, 149-157, doi:10.1016/j.icarus.2010.12.013, 2011. Fieber-Beyer, S.K., M.J. Gaffey, M.S. Kelley, V. Reddy, C.M. Reynolds, and T. Hicks, The Maria Asteroid Family: Genetic Relationship and a Plausible Source of Mesosiderites near the 3:1 Kirkwood Gap. Icarus, 213, doi:10.1016/j.icarus.2011.03.009, 524-537, 2011c. Fieber-Beyer, S.K., M.J. Gaffey, P.S. Hardersen, and V. Reddy,Near-infrared spectroscopy of 3:1 Kirkwood Gap asteroids: Mineralogical diversity and plausible meteorite parent bodies, Icarus 221, 593-602, dx.doi:10.1016/j.icarus.2012.07.029, 2012. Fieber-Beyer, S.K., and M.J. Gaffey, Near-Infrared Spectroscopy of 3:1 Kirkwood Gap Asteroids: A Battalion of Basalts, 44th Lunar and Planetary Science Conference, LPI Contribution No. 1719, p.1352, 2013. Fieber-Beyer, S.K., and M. J. Gaffey, M.J., Near-infrared Spectroscopy of 3:1 Kirkwood Gap asteroids II: Probable and plausible parent bodies; primitive and differentiated, Icarus 229, 99-108, doi:10.1016/j.icarus.2013.11.001, 2014. Fieber-Beyer, S.K., and M.J. Gaffey, Near-infrared spectroscopy of 3:1 Kirkwood Gap asteroids III. Icarus, 257, 113-125, doi:10.1016/j.icarus.2015.04.034, 2015. Gaffey, M.J., Observational and Data Reduction Techniques to Optimize Mineralogical Characterizations of Asteroid Surface Materials. Lunar. Planet. Sci. XXXIV, [abstract 1602], 2003. Gaffey, M.J., E.A. Cloutis, M.S. Kelley and K.L. Reed, Mineralogy of asteroids. In Asteroids III (W. F. Bottke, A. Cellino, P. Paolicchi and R. P. Binzel, Eds.), Univ. of Arizona Press, pp. 183-204, 2002. Hardersen, P.S., Near-IR Reflectance Spectroscopy of Asteroids and Study the Thermal History of the Main Asteroid Belt. Ph.D. Dissertation. Rensselaer Polytechnic Institute, Troy, New York, USA, 2003. Rayner, J. T., D. W. Toomey, P. M. Onaka, A. J. Denault, W. E. Stahlberger, and 3 others, SpeX: A Medium-Resolution 0.8 - 5.5 micron Spectrograph and Imager for the NASA Infrared Telescope Facility, PASP 115, 362, 2003. Reddy, V., Mineralogical Survey Of Near-Earth Asteroid Population: Implications For Impact Hazard Assessment And Sustainability Of Life On Earth, Ph.D. dissertation. University of North Dakota, Grand Forks, 2009.
DATA_SET_RELEASE_DATE 2015-11-19T00:00:00.000Z
START_TIME 2000-06-30T12:00:00.000Z
STOP_TIME 2014-01-31T12:57:19.000Z
MISSION_NAME SUPPORT ARCHIVES
MISSION_START_DATE 1965-01-01T12:00:00.000Z
MISSION_STOP_DATE 2015-01-01T12:00:00.000Z
TARGET_NAME 1215 BOYER
897 LYSISTRATA
3999 ARISTARCHUS
421 ZAHRINGIA
292 LUDOVICA
695 BELLA
879 RICARDA
1447 UTRA
974 LIOBA
908 BUDA
652 JUBILATRIX
1772 GAGARIN
3637 O'MEARA
1587 KAHRSTEDT
714 ULULA
248 LAMEIA
660 CRESCENTIA
1358 GAIKA
1368 NUMIDIA
2089 CETACEA
1722 GOFFIN
355 GABRIELLA
1854 SKVORTSOV
3345 TARKOVSKIJ
1379 LOMONOSOWA
3066 MCFADDEN
1501 BAADE
1018 ARNOLDA
6649 YOKOTATAKAO
787 MOSKVA
1960 GUISAN
1036 GANYMED
495 EULALIA
619 TRIBERGA
556 PHYLLIS
1166 SAKUNTALA
2497 KULIKOVSKIJ
623 CHIMAERA
1607 MAVIS
ASTEROID 6212
335 ROBERTA
1064 AETHUSA
ASTEROID
329 SVEA
3760 POUTANEN
198 AMPELLA
46 HESTIA
797 MONTANA
5676 VOLTAIRE
1158 LUDA
1644 RAFITA
875 NYMPHE
1391 CARELIA
TARGET_TYPE ASTEROID
INSTRUMENT_HOST_ID OBS376T3
INSTRUMENT_NAME SPEX
INSTRUMENT_ID I0046
INSTRUMENT_TYPE IMAGER
SPECTROMETER
NODE_NAME Small Bodies
ARCHIVE_STATUS LOCALLY ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : The spectra were obtained over several years (2000-2014); thus, nightly sky conditions varied. Uncertainties and point to point scatter differ in each asteroid spectrum. The uncertainty in each spectrum is affected by the level of the signal to noise achieved, changing atmospheric conditions, and instrument stability. The atmospheric water absorption bands at 1.4 and 1.9 microns may not be completely removed from the averaged spectrum. The uncertainties associated with each channel in each asteroid spectrum are standard errors of the mean of the values averaged to get the reflectance in that channel. These errors are not based on Poisson statistics, but are instead a measure of systematic variations among the individual data making up the combined spectrum. The May 2009 spectra start and end times of observations are listed as hh:mm as recorded from the observing logs; the fits headers for each spectrum were not able to be extracted due to a fire shortly after the IRAF extracted spectrum was transferred to a windows based machine.
CITATION_DESCRIPTION Fieber-Beyer, S.K., Fieber-Beyer IRTF Mainbelt Asteroid Spectra V3.0. EAR-A-I0046-3-FBIRTFSPEC-V3.0. NASA Planetary Data System, 2015.
ABSTRACT_TEXT The data set contains observations obtained with the NASA IRTF SpeX instrument covering the 0.7 to 2.5 micron near-infrared portion of the spectrum. The data set archives reduced, calibrated spectra which were obtained and used in Sherry Fieber-Beyer's Ph.D. dissertation at the University of North Dakota and archives reduced, calibrated spectra subsequent 2010. The research focused on asteroids in a zone centered on the 3:1 resonance. These spectra were used to mineralogically characterize asteroids in this zone in an attempt to identify their meteorite analogs.
PRODUCER_FULL_NAME SHERRY FIEBER-BEYER
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