NGC 330
Open star cluster in the constellation Tucana
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NGC 330 is an open cluster in the Small Magellanic Cloud. It is located in the constellation Tucana. It was discovered on 1 August 1826 by James Dunlop. It was described by Dreyer as "a globular cluster, very bright, small, a little extended, stars from 13th to 15th magnitude."[4] At an aperture of 31.0 arcseconds, the apparent V-band magnitude is 9.60, but at this wavelength, it also has 0.36 magnitudes of interstellar extinction.[2]
| NGC 330 | |
|---|---|
The star cluster NGC 330 Credit: Hubble Space Telescope | |
| Observation data (J2000 epoch) | |
| Right ascension | 00h 56m 17.6s[1] |
| Declination | −72° 27′ 47″[1] |
| Distance | 182000[1] |
| Apparent magnitude (V) | 9.60[2] |
| Apparent dimensions (V) | 2.8′ × 2.5′[3] |
| Physical characteristics | |
| Mass | 5.4×104[2] M☉ |
| Estimated age | 0.09±0.05 Gyr[2] |
| Other designations | ESO 029-SC 024.[1] |
| Associations | |
| Constellation | Tucana |
NGC 330 is quite young, at about 40 million years old, and has a large proportion of Be stars.[5] Its estimated mass is 5.4×104 M☉, and its total luminosity is 8.93×105 L☉, leading to a mass-to-luminosity ratio of 0.06 M☉/L☉.[2] All else equal, older star clusters have higher mass-to-luminosity ratios; that is, they have lower luminosities for the same mass.[2] About 34% of the massive star population in NGC 330 is estimated to be in a close binary star system; this is lower than clusters in the Large Magellanic Cloud and the Milky Way, but it is unknown if this is because NGC 330 is metal-poor or is older than the compared clusters.[5]
