Mz 1
# Mz 1

Mz 1 (Menzel 1), is a bipolar planetary nebula (PN) in the constellation Norma.

## Characteristics

Menzel 1 is a bright planetary nebula that has a prominent central ring of enhanced emission. One model of its structure is a three-dimensional hour-glass shape with a smoothly decreasing density starting from the waist or equator as measured outwardly to the poles. It is radially expanding at a rate of about 23 km/s and estimated to be around 4,500 to 10,000 years old and has its polar axis oriented at an angle of around 40° from the plane of the sky. Its central star is estimated to have a mass of 0.63 ± 0.05 $M_☉.$ In 1992 Schwarz, Corradi, & Melnick published narrow band images of Mz 1 in Hα and [OIII]. $H_2$ emission was observed in Mz 1 by Webster, Payne, Storey, Dopita (1988). However, despite its relative brightness, Mz 1 has only been studied in a few papers (Monteiro et al. 2005).

## History

Mz 1 was discovered by Donald Howard Menzel in 1922. (Menzel 1922)

