[vsnet-chat 1395] SN 1998ef in UGC 646

[Hitoshi YAMAOKA <yamaoka@rc.kyushu-u.ac.jp>]

cf. vsnet-chat 1394
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chat/msg01394.html
cf. vsnet-chart 110
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chart/msg00110.html
cf. vsnet-obs 16833
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chat/msg16833.html

Dear SN watchers,

  According to IAUC 7032, KAIT team has discovered a supernova 1998ef.
It is located at R.A. = 1h03m26s.87, Decl. = +32o14'12".4 (2000.0),
which is about 6" east and 2" south from the nucleus of the host
barred-spiral(?) galaxy UGC 646.  The new star is well near to the
nucleus.  Spectroscopy has performed and it is determined that this SN
is of type Ia. 

  There are some confusing foreground stars: GSC 0228201278 (GSC mag =
13.75) is located about 17" west from the nucleus; USNO 1200-00446148
(USNO R = 15.3) is located about 21" east and 10" north from the
nucleus.  Finding chart based on USNO A1.0 are available at:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chart/msg00110.html

  The host galaxy is rather further one.  Estimated with its recession
velocity, typical SNeIa on this galaxy would be expected to be 16.0
mag or so on their maximum (vsnet-chat 1394).  However, KAIT team has
reported that the magnitude at discovery (Oct. 18.3 UT) was 15.2 mag,
which is well brighter than expect.  It can be caused by the error of
the distance, but it is possible that this SN Ia 1998ef is
intrinsically bright one.  

From the early photometry (vsnet-obs 16833), SN 1998ef seems to be
still on the stage of rapid brightening.  Further magnitude estimates
are highly encouraged.

Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
yamaoka@rc.kyushu-u.ac.jp

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