S Monocerotis [SEP] constellation
S Monocerotis
S Monocerotis, also known as 15 Monocerotis, is a massive multiple and variable star system located in the constellation Monoceros. It is the brightest star in the Christmas Tree open cluster in the area catalogued as NGC 2264.
S Monocerotis is found within an open cluster and the Washington Double Star Catalog lists many companion stars. The closest and brightest is S Mon B, magnitude 7.8 and 3 arc seconds away. It is classified as B7 main sequence star with a mass of . The cluster contains another dozen
, who worked for the Coast Survey—a predecessor to the US National Geodetic Survey.
A similar grapefruit-sized globe made from two halves of an ostrich egg was found in 2012 and is believed to date from 1504. It may be the oldest globe to show the New World. Stefaan Missinne, who analyzed the globe for the Washington Map Society journal "Portolan", said it was "part of an important European collection for decades." After a year of research in which he consulted many experts, Missinne