M 37 (NGC 2099)

Summary

1. The history
2. To find M37
3. To observe M37
4. The stars of M37, and more

The history

M37 is the brightest of the three cluster that lie in the southern region of Auriga. His discovery, until 1985, was given to Messier (1764), although it seems that Le Gentil had observed it, and then missed, in 1749.

Today we credit G. B. Hodierna (1597-1660) for the first observation of all three of the SAuriga's clusters. This was proved in 1985 by an important article in the Journal for the History of Astronomy, by G. Foderą Serio (Osservatorio Astronomico di Palermo) and two her colleagues.

To find M37

M37 lies, as regards to the star q Aurigae, in a somewhat symmetric position with M36 (some 5°). M37 is eastward, M36 westward.

To observe M37

Dei tre ammassi dell'Auriga, M37 č il pił ricco di stelle, contandone circa 150 pił luminose di mag. 12.5, su un totale di forse 500.

The stars of M37 and more

This cluster contains at least a doze red giants, and the hottest stars of the main sequence are B9V-type: this data show that M37 is older than his neighbours, about 300 millions years

. His distance is controversial: the values range from 3,600 l.y. (K. Glyn Jones) to 4,600 (Burnham). His linear size, according to valued distance, range from 20 to 25 l.y.