Galaxies Messier 105, NGC 3384 & NGC 3389

M 105: Galaxy M 105 in Leo; 500 mm Cassegrain 3625 mm f/7.2; SBIG STL11K; 70+30+30+30 min LRGB; Bernese Highlands; © 2011 Radek Chromik


Pierre Méchain discovered the galaxy M 105 on 24th March 1781, just four or five days later thanM 95 and M 96, which are only about 1° away. For unknown reasons, this discovery did not make it into the original Messier catalog, which appeared in the 1784 «Connoissance des Temps». Independently of this, William Herschel came across this galaxy on 11th March 1784, which Dreyer later included in the «New General Catalogue» as NGC 3379. Since Méchain's discovery was in the same period as the discovery of the last objects in the Messier catalog, it was added in 1947 by Helen Sawyer Hogg as M 105 together with M 106 and M 107. [217]

Physical Properties

M 105 is an elliptical galaxy and a member of the approximately 40 million light-years distant Leo I group of galaxies, which contains M 95, M 96 and other weaker galaxies. Like most elliptical galaxies, M 105 appears to be fairly structureless and inactive, but observations with the Hubble Space Telescope have shown that new stars are still emerging in the galaxy believed to be dead. Measurements of the star movements in the center revealed a supermassive black hole of about 200 million solar masses. Measurements of the redshift over the past 20 years show a heliocentric velocity of 874 km/s to 911 km/s and a distance of 8 Mpc to 17 Mpc (26 to 55 million light years). [145, 215]

The galaxy NGC 3384 was discovered by Wilhelm Herschel on 11th March 1784. At NED one finds a morphological type according to de Vaucouleurs of SB0^-(s), which is a lenticular galaxy in transition to a bar spiral. According to Zimbab, measured heliocentric speeds are in the range from 563 km/s to 735 km/s and distances from 8 Mpc to 11 Mpc (26 to 35 million light years). The galaxy is therefore closer than M 105. [145, 194, 196]

At a distance of 19 Mpc to 21 Mpc (62 to 69 million light years), the spiral galaxy NGC 3389 is slightly further away than the other two. It is of the morphological type SA(s)c and was also discovered by Wilhelm Herschel on 11th March 1784. [145, 194, 196]

Revised+Historic NGC/IC, Version 22/9, © Dr. Wolfgang Steinicke [277]
NameRADecTypebMagvMagB-VSBDimPAzD(z)MDDreyer DescriptionIdentification, Remarks
NGC 337910 47 49.5+12 34 52Gx (E1) × 4.8710.00303912.8410.390vB, cL, R, psbM, rM 105, UGC 5902, MCG 2-28-11, CGCG 66-18
NGC 338410 48 16.7+12 37 43Gx (E/SB0) × 2.7530.0023489.9211.590vB, L, R, psmbM, 2nd of 3NGC 3371, UGC 5911, MCG 2-28-12, CGCG 66-21, PRC C-34
NGC 338910 48 28.0+12 31 59Gx (Sc)12.411.90.513.22.9 × 1.31120.00436418.4321.290F, L, E pf, vglbM, 3rd of 3NGC 3373, UGC 5914, MCG 2-28-13, CGCG 66-22

Finder Chart

The three galaxies are located in the constellation Leo, roughly in the middle between the stars Chertan (θ Leonis) and Regulus (α Leonis), only about 1° northeast of M 95/96. The best observation time is in the months of January to May.

Finder Chart Galaxies Messier 105, NGC 3384 & NGC 3389
Galaxies Messier 105, NGC 3384 & NGC 3389 in constellation Leo. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Visual Observation

Description pending ...

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