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ATEL # 2822; M.Hicks (JPL/CalTech), B. Buratti (JPL/CalTech)
on 30 Aug 2010; 22:40 UT
Password Certification: Michael D. Hicks (Michael.Hicks@jpl.nasa.gov)
Subjects: Optical, Asteroids, Solar System Objects
We obtained long-slit CCD spectrograms of the near-Earth asteroids 2010 MF1 and 138404 (2000 HA24) using the Palomar 5-m Hale Telescope equipped with the facility dual-channel spectrometer on August 10 2010. 2010 MF1 was discovered June 18 2010 by the Siding Spring Survey (MPEC 2010-M28) while 2000 HA24 was discovered by the LINEAR NEO survey on April 28 2000 (MPEC 2000-J10). Both minor planets have been designated as Potentially Hazardous Asteroids by the Minor Planets Center, although they currently pose no significant impact threat. We note that the delta-V requirements for a spacecraft rendezvous with 2000 HA24 are modest (dV = 5.80 km/sec).
Table 1 summarizes our observational circumstances, with the expected V magnitude computed assuming a phase parameter G=0.15 using the orbital elements and Absolute Magnitude H_V maintained by the JPL HORIZONS database. Table 2 lists the solar analog stars used to generate the composite normalized reflectance spectra, as shown in Figures 1-2 .
A comparison of our optical spectra with the 1341 asteroid spectra archived in the SMASS II database (Bus & Binzel 2002) was used to determine taxonomy. Table 3 list the five best-fit SMASS II analogs for each object. We identify 2010 MF1 as a new Vestoid, with a spectrum best matched by the main-belt asteroid 4 Vesta, and we assign a K-type classification (a subset of the S-family which may suggest a highly weathered surface) for 2000 HA24.
Both asteroids are well placed for further physical characterization, particularly rotational lightcurve studies. 2010 MF1 remains at a high northerly declination and brighter than V~19 though October 14 2010, while 2000 HA24 remains near Dec = -11 deg and brighter than V~19 though October 22 2010. Collaborations with other observers are welcome.
Copyright 2010. California Institute of Technology. Government sponsorship acknowledged.
Table 1: Observational Circumstances. Object Name r (AU) delta (AU) phase (deg) H (mag) V (mag) Exp Time (min) 2010 FM1 1.025 0.132 81.5 19.5 18.0 30.0 2000 HA24 1.296 0.288 10.1 20.9 19.0 35.0
Table 2: Solar Analog Stars Object Name Solar Analog Stars 2010 MF1 16 Cyg B, 115-268 2000 HA24 115-268
Table 3: Best-fit SMASS II spectral analogs. TAXONOMIC CLASS MISFIT OBJECT NAME (THOLEN) (BUS) - for 2010 MF1 - 1.802 4 Vesta V V 2.009 3498 Belton V 2.160 3265 Fletcher V 2.175 1324 Knysna Sq 2.182 4051 Hatanaka Sq - for 2000 HA24- 0.863 606 Brangane TSD K 0.899 2271 Kiso T 0.907 559 Nanon C Xk 0.914 2724 Orlov K 0.940 2929 Harris T