first_spec_class second_spec_class prob_first_spec_class prob_second_spec_class taxonomy wavelength author ref method S Q 0.720000 0.280000 Mahlke VIS Mahlke 2022A&A...665A..26M SPEC Sq Bus VIS Binzel 2019Icar..324...41B SPEC Sq Bus VIS Bus 2002Icar..158..146B SPEC