The supernova ring revisited. 2. Distance to the lmc

I derive an upper limit to the distance to SN 1987A of \dsn<46.77\pm 0.76\,\kpc, or a distance modulus \mu_\sn<18.350\pm 0.035. If SN 1987A lies in the plane of the Large Magellanic Cloud (LMC) and hence 500 pc in front of the LMC center, this implies \mu_\lmc<18.37\pm 0.04. The determination rests on a new measurement of the caustics in the ionized-emission light curves of

t_-=75.0\pm 2.6\,

days and

t_+=390.0\pm 1.8\,

days. The estimate assumes that the ring is circular. This assumption is shown to be consistent with the available data and can be subjected to a future precise test. Moreover, I have previously shown that modest deviations from circularity (eccentricities

e<0.4

) affect the result by

<1\%

. The upper limit to the distance modulus to M31 is

\mu_{\rm M31} < 24.43\pm 0.06

. If the response function of the supernova-ring gas is prompt, then these upper limits become equalities.

References(9)

Figures(0)

[1]

E. Dwek
,
J.E. Felten

- Astrophys.J. 387 (1992) 551

[2]

1989

C. Fransson
,
A. Cassatella
,
R. Gilmozzi
,
R.P. Kirshner
,
N. Panagia

et al.

- Astrophys.J. 336 (1989) 429

[3]

1994a (Paper I)

A. Gould

- Astrophys.J. 425 (1994) 51

[4]

1994b

A. Gould

- Astrophys.J. 426 (1994) 542

[5]

1992

G.H. Jacoby

- Publ.Astron.Soc.Pac. 104 (1992) 599

[6]

1991

P. Jakobsen

- Astrophys.J. 369 (1991) L63

[7]

R. Clegg, P. Meikle, & I. Stevens (eds.) 1994, 34th Herstmonceux Conference in press

P. Lundqvist

[8]

1991

N. Panagia
,
R. Gilmozzi
,
F. Macchetto
,
H.-M. Adorf
,
R.P. Kirshner

- Astrophys.J. 380 (1991) L23

[9]

1994, ApJ, submitted

P. Plait
,
P. Lundqvist
,
R. Chevalier
,
R. Kirshner