M105
NGC 3379
Elliptical
物性
位置と識別子
可視性
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M105について
説明
M105 is an elliptical galaxy in Leo, about 32 million light-years from Earth. It is the brightest elliptical galaxy in the Leo I Group (M96 Group) and forms a visual trio with NGC 3384 and NGC 3389. M105 harbors a supermassive black hole of about 200 million solar masses at its center.
観測のコツ
Located about 48 arcminutes north of M96. In a telescope it appears as a bright, round, featureless glow with a concentrated nucleus — characteristic of elliptical galaxies. NGC 3384 lies just 7 arcminutes to the northeast, and the two form a close pair. NGC 3389 is visible about 10 arcminutes further south. The trio makes an attractive group in moderate-aperture telescopes. Best observed from February through May.
歴史
Discovered by Pierre Mechain on March 24, 1781. It was not in Messier's published catalog but was added in 1947 by Helen Sawyer Hogg based on Mechain's letter describing the discovery.
豆知識
M105 was one of the last objects added to the Messier catalog, not included until 1947. Hubble Space Telescope observations revealed that stars in the central few light-years orbit the 200-million-solar-mass black hole at speeds up to 430 km/s. Despite appearing smooth and featureless, M105 has been found to contain a small disk of young blue stars in its center — unusual for an elliptical galaxy.
コミュニティ写真 (1)
Credit: Credit: ESA/Hubble & NASA, C. Sarazin et al.. License: CC BY 4.0. (Wikimedia Commons)
Skybred Feb 28, 2026