SN 1989B Light Curve Analysis.


ABSTRACT

The file SN 1989B.GIF is presented to display data associated with monitoring a SN event by amateur SN observers. The data was weaned from the observations of various individuals who were involved in the project of discovering and monitoring SNe (SUNSEARCH [1985-1991]). In the light curve depicting their observations, definite trends are noted, here is a "thumb-nail" analysis of the the magnitude estimations of the bright SN (1989B) in the galaxy NGC 3627 (M66). When the event was discovered information involving a standardized set of photometrically sequenced comparison stars was sent to each participant, weaned from "The Type II SN 1973-R in NGC 3627", (A&A.,_56_, 1977, F. Ciatti and L. Rosino, (1977). The observations were inserted against the V magnitude templete of BL, CCD photometric data, (Wells et. al, (1994) and a color trend (B-V) histogram of the mean type Ia SN (BL)(nutemp.gif). Key Words: Amateur Observations, Supernova, Magnitude Estimates, 1989B

DATA

At maximum light the observations are in pretty good agreement with the V-templete. At later times (~15 days onward) some of the estimates seem to break away from the V-band in the direction of the B-band (fainter magnitude)(Note: there is a gap in observations to this point in the event [~day 5-17]), while others follow the V-band in good agreement with epoch decay. Notice also the color curve (B-V) breaks away from the V curve at about the 4 day (from maximum) mark and follows its trend of progression throughout the event. It is only conjecture at this time wheather any of the estimates allowed for any color or transformation corrections (the photometrically sequenced comparison stars used in the cited paper had very little color diversity in their values) thus, personal equation (see J. Isles,1990 regarding visual magnitude pitfalls) seems to have had an effect on at least some of estimates, which appear to be a direct result of the color trend of the type Ia event. Perhaps in the future some method to alliviate these scatter points and align these values can be addressed.... (Note: the two solitary points before maximum light represent this authors' pre-discovery magnitude estimate (IAUC# 4735) and R.Evans' discovery estimate).

References: 

	B. Leibundgut- Astron. & Astrophy. 89, p. 537-579
	(1991)

	B. Leibundgut- AJ., 105, Jan., (1991)

	M.M. Richmond et.al- AJ., 107, May, (1994)

	M.M. Phillips- AJ., 103, May, (1992)

	M.M. Phillips- ApJ., 413, L105, (1993)

	G. de Vaucouleurs and H.G. Corwin- ApJ., 295,
	August 15, (1985)

	G. deVaucouleurs, Corwin, Skiff- P.A.S.P.,106,
	Feb.,(1994)

	M. Pierce, G. Jacoby- AJ., Vol. 110, #6,
	December, (1995)

	D. Branch et. al- ApJ., 421, L87-90, Feb., (1994)

	L.Wells et. al- AJ., 108,(6), December (1994)

	J. Isles- Webb Society Deep Sky Observers
	Handbook, Vol. 8 "Variable Stars" (pg. 40)(1990)

	G. Thompson/ J. Bryan "Supernovae Search
	Charts (Cambridge University Press, (1989)