PEAK BRIGHTNESSES OF HISTORICAL SUPERNOVAE AND THE HUBBLE CONSTANT

This paper reports on the peak magnitudes (m(max)) and peak absolute m agnitudes (M(max)) of SN 1604, SN 1572, SN 1006, and SN 185 utilizing three techniques that have not been previously applied to the historic al supernovae. SN 1604 is at a distance (D) of 3.4 +/- 0.3 kpc, with a visual extinction (A) of 3.27 +/- 0.14 and is unlikely to be a Type I a supernova. Its light curve shape is like that of a fast Type Ia even t with m(max) = -3.02 +/- 0.10 and M(max) = -18.95 +/- 0.26. SN 1572 i s at D = 2.35 +/- 0.20 kpc, with A = 2.25 +/- 0.16, and is likely to b e a Type Ia or Ib supernova. Its light curve shape is like that of a v ery fast Type Ia event with m(max) = -4.53 +/- 0.18 and M(max) = -18.6 4 +/- 0.31. SN 1006 is most likely a Type Ia event at 1.59 +/- 0.13 kp c with an extinction of 0.32 +/- 0.03 and a peak near -5 mag. Even tho ugh the available light curve is sparse and crude, the supernova is ce rtainly subluminous with a peak absolute magnitude of approximately -1 7. SN 185 has a peak magnitude that can only be constrained to be brig hter than roughly -7.5, has an uncertain remnant, and is unlikely to e ven be a supernova. These four historical supernovae are useless for s olving the Hubble constant question for three reasons: First, none of them is guaranteed to be a Type Ia event and SN 185 is unlikely to eve n be a supernova. Second, the various calibration, template, and proce dural problems combine to make the uncertainties large. Third, the mea surement errors alone yield uncertainties that are sufficiently large to preclude a solution of the Hubble constant problem.