; Given type (string, eg.g, "O"), subtype (float, e.g. 3)
; and class (integer), return star radius (in km) from
; AQ 4th ed
;

function aq_starr, type, subtype, class

  rsun = 6.95508e5 ; solar radius in km
  CASE class OF
    5: begin ; Main sequence
	    CASE type OF
		'O': begin 
			x = [3,5,6,8] & y = [15,12,10,8.5]*rsun
		     end
		'B': begin 
			x = [0,3,5,8] & y = [7.4, 4.8, 3.9, 3.0]*rsun
		     end
		'A': begin 
			x = [0,5] & y = [2.4, 1.7]*rsun
		     end
		'F': begin 
			x = [0,5] & y = [0.5, 0.3]*rsun
		     end
		'G': begin 
			x = [0,5] & y = [1.1, 0.92]*rsun
		     end
		'K': begin 
			x = [0,5] & y = [0.85, 0.72]*rsun
		     end
		'M': begin 
			x = [0,2,5,8] & y = [0.60, 0.50, 0.27, 0.10]*rsun
		     end
	  ENDCASE
       end
    3: begin ; giants. 
    	    CASE type OF
		'B': begin 
			x = [0,5] & y = [15, 8]*rsun
		     end
		'A': begin 
			x = [-5,18] & y = [8, 6]*rsun
		     end
		'F': begin 
			x = [-15,8] & y = [8,6]*rsun
		     end
		'G': begin 
			x = [0,5] & y = [6,10]*rsun
		     end
		'K': begin 
			x = [0,5] & y = [15,25]*rsun
		     end
		'M': begin 
			x = [-1,0] & y = [25,40]*rsun
		     end
	  ENDCASE
       end
    1: begin ; super giants. T
	    CASE type OF
		'O': begin 
			x = [5,6,8] & y = [30,25,20]*rsun
		     end
		'B': begin 
			x = [0,5] & y = [30,50]*rsun
		     end
		'A': begin 
			x = [0,5] & y = [60,60]*rsun
		     end
		'F': begin 
			x = [0,5] & y = [80,100]*rsun
		     end
		'G': begin 
			x = [0,5] & y = [120,150]*rsun
		     end
		'K': begin 
			x = [0,5] & y = [200,400]*rsun
		     end
		'M': begin 
			x = [0,2] & y = [500,800]*rsun
		     end
	  ENDCASE
       end
  ELSE: begin ; out of bounds! 
    print, 'aq_teff: spectral type out of bounds'
    return,-100
    end
  ENDCASE

  res = poly_fit(x, y, 1)
  starr = poly(subtype,res)
  return, starr
end