The Butterfly Cluster (cataloged as Messier 6 or M6 , and as NGC 6405 ) is an open cluster of stars in the southern constellation of Scorpius . Its name derives from the resemblance of its shape to a butterfly .
7-530: The first astronomer to record the Butterfly Cluster's existence was Giovanni Battista Hodierna in 1654. However, Robert Burnham Jr. has proposed that the 2nd century astronomer Ptolemy may have seen it with the naked eye while observing its neighbor the Ptolemy Cluster (M7). Credit for the discovery is usually given to Jean-Philippe Loys de Chéseaux in 1746. Charles Messier observed
14-503: A slightly higher abundance of elements heavier than helium compared to the Sun; what astronomers refer to as the metallicity . 120 stars, ranging down to visual magnitude 15.1, have been identified as most likely cluster members. Most of the bright stars in this cluster are hot, blue B-type stars but the brightest member is a K-type orange giant star , BM Scorpii, which contrasts sharply with its blue neighbours in photographs. BM Scorpii,
21-532: Is 23 ly (7 pc) below the galactic plane , and it will cross the plane every 29.4 Myr. Giovanni Battista Hodierna Giovanni Battista Hodierna , also spelled as Odierna (April 13, 1597 – April 6, 1660) was an Italian astronomer at the court of Giulio Tomasi , Duke of Palma (Palma di Montechiaro). He compiled a catalogue of comets and other celestial objects containing some 40 entries, including at least 19 real and verifiable nebulous objects that might be confused with comets. Hodierna
28-553: Is classed as a semiregular variable star , its brightness varying from magnitude +5.5 to magnitude +7.0. There are also eight candidate chemically peculiar stars . The cluster is located 24.59 ± 0.13 kly (7.54 ± 0.04 kpc) from the Galactic Center and is following an orbit through the Milky Way galaxy with a low eccentricity of 0.03 and an orbital period of 204.2 Myr. At present it
35-419: The cluster on May 23, 1764, and added it to his Messier Catalog . Estimates of the Butterfly Cluster's distance have varied over the years. Wu et al. (2009) found a distance estimate of 1,590 light-years , giving it a spatial dimension of some 12 light years. Modern measurements show its total visual brightness to be magnitude 4.2. The cluster is estimated to be 94.2 million years old. Cluster members show
42-685: Was born in Ragusa , Sicily and died in Palma di Montechiaro . While serving as a Roman Catholic priest in Ragusa, he also practised astronomy. In 1654 he published a book entitled De systemate orbis cometici, deque admirandis coeli characteribus that contained a catalogue of celestial objects and a list of double stars. The work anticipated Messier's catalogue and the double star catalogues by Christian Mayer and William Herschel , but had little impact. Messier seems not to have known of it. Hodierna
49-403: Was prolific in publication, and his interests spanned many disciplines. In addition to his astronomical observations, he utilized optic microscopes to study insects, publishing on the multifaceted eye of flies and that in bee colonies only the queen is oviparous. This article about an Italian astronomer is a stub . You can help Misplaced Pages by expanding it . This Sicily -related article
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