function star_radius,teff,av,kmag,ra,dec
; this routine estimates the radius of a star given its effective temp
; teff, its V extinction av, its Kepler magnitude kmag, and its RA and
; Dec (for computing galactic latitude).
; For now, strictly dwarf radii, for teff >= 5560
; From AQ 4th ed. p. 388

tt=[5560.,5940.,6650.,7300.,8180.,9790.,11400.,15200.,19000.,30000.,42000.]
rr=[.92,1.1,1.3,1.5,1.7,2.4,3.0,3.9,4.8,7.4,12.]

if(teff ge 5560.) then begin
  rad=interpol(rr,tt,teff)
endif else begin
  rad=10.*(5560./teff)^3.4             ; gives r=40 at M0 = 3690K
endelse

return,rad

end