Messier 89: Elliptical Galaxy in Virgo

M89 is one of the quieter galaxies of the Virgo Cluster: a small, round glow that is easy to pass over. It is worth picking up on a tour of the cluster core because it lies so close to M87 and M90.

What it is

M89 is an elliptical galaxy, and one of the roundest known: it looks almost perfectly circular, though it may be an elongated galaxy that we happen to see end-on. It lies about 50 million light-years away, and its bright inner part spans roughly 60,000 light-years.

Deep long-exposure images show that M89 is larger than it looks in a telescope. A faint halo of stars surrounds it, with shells and plumes that are probably debris from smaller galaxies it has absorbed. It has many globular clusters and a weak radio source at its center, a sign of a supermassive black hole that is only mildly active.

When to see it

From about 40°N, M89 is highest around midnight in early April and around 10 p.m. standard time (11 p.m. daylight time) in early May, reaching about 63° above the southern horizon. It is also visible from most of the Southern Hemisphere, in the northern sky during autumn.

How to find it

Start from M84 and M86, at the midpoint of the line from Denebola, the star at Leo's tail, to Vindemiatrix (Epsilon Virginis). Move about 1.5° southeast to M87, then about 1.2° due east to M89. M90 lies only about 40′ north of M89, so both fit in a low-power field. Rho Virginis, a 5th-magnitude star, is about 2.7° to the south-southeast of M89 and makes a useful check.

What you will see

M89 is too faint and small for most binoculars. A 70–100 mm telescope under a dark sky shows a small round glow with a brighter center, much like a fainter version of M87; from the suburbs it can be difficult. A 200 mm telescope shows the round halo and a sharp, bright core, but no structure; the shells seen in photographs are far too faint to see by eye. Filters do not help.

History

Charles Messier found M89 on March 18, 1781, one of eight objects he logged in the Virgo region that night, and noted it as very faint. Its faint outer shells and plumes were found much later in deep photographic studies of the Virgo Cluster.