[vsnet-chat 829] More Added Tidbits On SN 1998aq

["Steve H. Lucas" <76620.1721@compuserve.com>]

Supernovae Collegues:

As a compliment to Mr. Hitoshi's excellant nomenclature of the host galaxy
for SN 1998aq, I might add that NGC 3982 is also considered a member of the
Ursa Major I North Cloud, a lesser of four clouds (South, X, and Z) (from
an unpublished article by James T. Bryan and Harold G. Corwin Jr., _Atlas
of the Ursa Major I North Cloud_, released in 1989). The V (subset t)
photoelectric magnitude for the entity is given as 11.1, the B-V (subset T)
Color Index=0.7, the surface brightness per square arc minute at the major
isophotal diameter=12.7.

This Cloud "has a membership of 37 galaxies of which 32 are spirals, 2 are
lenticular, 1, is irregular, 1 is elliptical and 1 is peculiar. Some
noteworthy galaxies residing within this cloud are: NGC's 3631(SNe 1964A,
SN1965L), 3733 (SN1980D), 3756 (SN1975T), 3913 (SNe 1963J, SN 1979B), 3992
(SN 1956A), Anon.1156+5259 (SN 1964E), and 4102 (SN 1975E). The Distance
Modulus on an average for six galaxies= 31.13, which yields a distance of
~16.8 Mpc (The major diameter of the Cloud is 11.1 degrees or 3.3 Mpc).
This yields an estimated Hubble parameter of 72.5 km/sec/Mpc in the
vicinity of the Cloud by implementing the formula V avg.=1218 km/sec/Mpc
(based on an average of 37 radial velocites) / the distance (Dmpc)=16.8
Mpc". 

A supernova in this Cloud (per the abovementioned paper) would be ~12.6 for
a type I, and ~14.6 for a type II (this infers a Mv= -18.5 and -16.5
respectively), which agrees well with Mr. Hitoshi's findings. 
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Addendum: In my posted message of 3/28/98 to VSNET, and ISN chats there is
an error regarding the galaxy NGC 3877....

>>"The distance modulus is ~31.37 (Ho=50km/sec per Mpc) yielding an
approximate distance of 25MLY (24,600,081)"<<. 

This should read: ~18.79 Mpc, or ~61M light years. Thanks to Stan Howerton
for the note, and keeping me honest <g>.
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Cheers,

Steve H. Lucas
International Supernovae Network

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