M76 is currently classed as a type of bipolar planetary nebula (BPN), composed of a ring which we see edge-on as the central bar structure, and two lobes on either opening of the ring. The progenitor star ejected the ring when it was in the asymptotic giant branch, before it had become a planetary nebula. Soon afterward the star expelled the rest of its outer layers, creating the two lobes, and leaving a white dwarf as the remnant of the star's core.[3][4] Distance to M76 is currently estimated to be 780 parsecs or 2,500 light years,[5] making the average dimensions about 0.378 pc. (1.23 ly.) across.[6]
The total nebula shines at the apparent magnitude of +10.1 with its central white dwarf or planetary nebula nucleus (PNN) at +15.9v (16.1B) magnitude.[1] The nucleus has a surface temperature of about 88,400 K. It has a radial velocity of −19.1km/s.[7]
The Little Dumbbell Nebula derives its common name from its resemblance to the Dumbbell Nebula (M27) in the constellation of Vulpecula. It was originally thought to consist of two separate emission nebulae so it bears the New General Catalogue numbers NGC 650 and 651.
^van Hoof, P. A. M.; Van de Streene, G. C.; Exter, K. M.; Barlow, M. J.; Ueta, T.; Groenewegen, M. A. T.; Gear, W. K.; Gomez, H. L.; Hargrave, P. C.; et al. (2013-11-28). "A Herschel study of NGC 650". Astronomy & Astrophysics. Retrieved 2024-02-19.