Bright Sn in NGC 3877

Bright Sn in NGC 3877

A bright supernova, 1998S, has been found on March 3 by Chinese astronomers at Beijing Observatory.

1998S is located in NGC 3877 an UMa galaxy at R.A. = 11h46m06s, Decl. = +47o29'.0. Magnitude at discovery was 15.2 and a day later it was measured 13.5.

Spectrum with Keck I show this object to be a type II event. The supernova is easily seen with an 8" telescope from suburban skies: use medium to high powers. The galaxy is close to M106, well placed in the evening sky.

Recent magnitude estimates show the star at around magn 12. A prediscovery image shows the sn at magn 16.0 on March 2.7. Use this chart to estimate visually the supernova (indicated by an X) and send reports to Stefano Pesci

An image by Bill Beam from Alaska on March 26: and a light curve with observations to March 25 from VSNet, ISN and IAUCs

Norwegian Astronomical Society - Variable Star Section


[Compiled by Bjorn H. Granslo (last update 1998 March 11)]
B.Granslo has prepared a finder and sequence chart for this supernova. It covers a field of 35'x35' and shows stars down to magnitude 15 and is mainly based on the GSC and USNO catalogues. It can be retrieved from the following URL:

Finder chart

Below follows a list of field and sequence stars located within ~20' from SN 1998S in NGC 3877:

1 HIP 57399 11h46m03.0s 4746'46" 3.69 1.18 Sp.KOIII
2 HIP 57349 11h45m31.0s 4740'03" 8.06 0.62 Sp.G2V
3 HIP 57385 11h45m55.5s 4732'51" 10.00 0.78 H Sp.Ko
4 TYC 3452-1157 11h47m12.9s 4747'15" 10.04 0.6 T
5 TYC 3452-1079 11h47m39.9s 4732'41" 11.20: TI (b-r)=+0.5
6 TYC 3452-1149 11h45m44.9s 4747'42" 11.8 TI
7 GSC 3452-0905 11h47m09.0s 4723'34" 11.9: G1
8 GSC 3452-1238 11h45m26.8s 4748'32" 12.2: G2 (b-r)=+0.7
x GSC 3452-1101 11h45m35.6s 4733'12" 12.5: G2 (b-r)=+1.1
y GSC 3452-1061 11h46m29.2s 4731'09" 12.6: G2 (b-r)=+0.2
A GSC 3452-1170 11h46m20.1s 4735'32" 12.6: G2 (b-r)=-0.3
B GSC 3452-1091 11h45m41.5s 4732'47" 13.2: G2 (b-r)=+0.6
C GSC 3452-0978 11h45m30.1s 4726'41" 13.8: G2 (b-r)=+1.1
D GSC 3452-0997 11h46m38.0s 4727'36" 14.5: G1
E GSC 3452-0977 11h45m34.8s 4726'49" 15.0: G1 (b-r)=+1.6

Identifications are from TA E-Circular 1278 (capital letters) and NAS.VSS (others). Positions are given to an accuracy of 0.1s in R.A. and 1" in Decl. V-magnitudes followed by a colon (:) are uncertain. Accurate photometry is currently available only for stars 1, 2 and 3. Star 1 is Chi UMa. Star 5 appears to be double. References to positions and magnitudes are H = Hipparcos Catalogue, T = Tycho Catalogue, TI = Tycho Input Catalogue, G1 = Guide Star Catalogue, Ver. 1.1 [GSC] (single entry), G2 = GSC (mean of two entries). Colour indices (b-r) are based on the PPM USNO-A1.0 catalogue. The catalogues were accessed via the VizieR service of CDS, and the compiler wish to thank CDS for this service.