Lenticular Galaxy NGC 632 and Supernova 1998es

Supernova 1998es in NGC 632

The field of view is about 5x7 arc minutes, with north at the top. The Nov. 19th image was taken under poor conditions with increasing low level fog.

A 1993 Astro-Physical Journal article noted that NGC 632 is a lenticular galaxy with a bright nucleus surrounded by a complex circumnuclear emission-line region resolved into bright clumps of emission. Also the nucleus has a strong H II region spectrum and is an example of nuclear starburst activity (i.e. runaway star formation) with considerable circumnuclear star formation.

Based on the published red shift, a rough distance estimate for NGC 632 and supernova 1998es is: 167,000,000 light years, and the galaxy is 73,000 light years in diameter.

This is the data on galaxy NGC 632:

The following is the data on SN 1998es:

Discovered: November 13th, 1998, by Lick Observatory Supernova Search

From IAU Bulletin 7054 (11/19/98):

....Harvard-Smithsonian Center for Astrophysics reports that a spectrum of SN 1998es features a blue continuum with strong absorption features at 374, 429, and 498 nm, and a weak, broad feature at 610 nm. The spectrum is generally similar to that of the peculiar type-Ia SN 1991T ..... with the exception of the absorption at 374 nm. The 374-nm absorption was seen in the SN 1991T-like supernova 1998ab (IAUC 6858) and is presumably due to Ca II H and K. ......recession velocity of 3168 km/s for NGC 632 implies a supernova expansion velocity of 19,000 km/s....... The morphological classification of NGC 632 is 'lenticular, uncertain', but it has a nuclear starburst with a diameter of 18 arc seconds, and the position of SN 1998es is projected near the edge of the star-forming region.

Visual observations: Just after imaging this supernova at UT 4:21 November 19th, 1998, four members of the Kopernik Astronomical Society were able to visually observe supernova 1998es using our 20 inch F/8 telescope at 320x. Under poor sky conditions the supernova and a close foreground star were clearly observed embedded in the outer halo of light surrounding the brighter nucleus of NGC 632. We also easily observed the supernova under much better sky conditions on Dec. 10th, 1998 around 4:00 UT.

Click below to

Return to Images Page

George Normandin, KAS