Galaxy NGC 660

NGC 660
NGC 660: Image taken with 8.1 m Gemini telescope on Mauna Kea. © 2012 Gemini Observatory/AURA [291]


On 16 October 1784 William Herschel discovered a faint nebula which he cataloged as II 253 and noted: «Pretty bright, pretty large, extended brighter in the middle, resolvable.» [463] John Herschel included it in his «General Catalogue» of 1864 with the designation GC 390. [467]

Sir Robert Ball, an assistant of Lord Rosse at Birr Castle observed the nebula with the giant 72 inch telescope and described it as follows: «a fine neb of the character of the neb in Andromeda. Considerably bright, very large, extended E 37.1°, possibly curved and with details. Extended Nucleus which was suspected to be in two parts or have some peculiarity.» A later observation by Dreyer reads «Pretty bright, pretty large, much extended 41°. Looks like a brush, fades away gradually south-following, more sharply defined north-preceding. Condensation in north following end.» [364]

On 30 September 1890 American astronomer Lewis Swift discovered IC 148 using the 12 inch refractor is that at Lick Observatory. [277]

Physical Properties

NGC 660 is a polar ring, starburst galaxy. It has a highly inclined, severely tidally-disturbed disk which is surrounded by a gas-rich, polar ring. Mostly such a feature is prent in elliptical S0 group of galaxies. The disk is viewed close to edge-on with an inclination of 70° and is crossed by a prominent dust lane. The inclination of the ring varies from about 45°-55° with respect to the plane of the disk and is not truly polar. NGC 660 shows signs of an outflow of hot gas along its minor axis. Dust grains located ~2.5 kpc from the stellar disk contribute to this phenomenon. Polarization from scattering is observed away from the minor axis, suggesting possible displacement of grains from the stellar disk due to tidal forces during galactic collisions, likely involving a massive, metal-rich spiral galaxy. Also the presence of a warped disk and the ring is a sign that this galaxy had a collision in the past. [295]

Revised+Historic NGC/IC Version 22/9, © 2022 Dr. Wolfgang Steinicke [277]
Name RA Dec Type bMag vMag B-V SB Dim PA z D(z) MD Dreyer Description Identification, Remarks
NGC 660 01 43 01.8 +13 38 37 Gx (SBa/PRG) 12.0 11.2 0.8 14.5 8.3 × 3.2 170 0.002835 11.97 13.450 pB, pL, E, bM, r UGC 1201, MCG 2-5-13, CGCG 437-12, IRAS 01403+1323, PRC C-13
IC 148 01 42 26.9 +13 58 36 Gx (Irr) 13.5 12.8 0.7 14.0 3.5 × 1.1 50 0.002582 10.91 10.800 eeF, pS, v diffic, II. 253 sf UGC 1195, MCG 2-5-11, CGCG 437-10

Finder Chart

The galaxy NGC 660 is located in the constellation Pisces. The best time to observe is July to January, when it is highest at night.

Finder Chart Galaxy NGC 660
Galaxy NGC 660 in constellation Pisces. 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]

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