Messier 35

Lore & Background

Messier 35 was discovered by Philippe Loys de Chéseaux around 1745 and independently discovered by John Bevis before 1750. The compact open cluster NGC 2158 lies directly southwest of it. Leonard & Merritt (1989) computed the mass of M35 using a statistical technique based on proper motion velocities of its stars, finding the mass within the central 3.75 parsecs to be between 1,600 and 3,200 solar masses. Bouy et al. in 2015 found a mass of around 1,600 M☉ within the central 27.5' × 27.5′. There are 305 stars that can be intrinsically shown to be extremely likely to be members, and up to 4,349 averaging the 50% membership probability, from kinematic and spectral data published before 2015. The cluster's metallicity is [Fe/H] = −0.21±0.10.

Reader's Guide

Messier 35 is significant as a relatively nearby open cluster that has been studied for its stellar population and dynamics. The article notes that of 418 probable members, Leiner et al. in 2015 found 64 that have variable radial velocities, indicating they are binary star systems. Four probable members are chemically peculiar, while HD 41995, which lies in the telescopic angular cluster field, shows emission lines. Hu et al. in 2005 found 13 variable stars in the field, with at least three suspect as cluster members. The cluster's legacy includes its use in studies of stellar membership and binary fractions, as well as its visual prominence as a large, scattered cluster in the night sky.

Did You Know?

• M35 was independently discovered by Philippe Loys de Chéseaux around 1745 and by John Bevis before 1750.
• Of 418 probable members, 64 are binary star systems with variable radial velocities.