NGC 178
| Galaxie NGC 178 / IC 39 | |
|---|---|
 (c) ESA/Hubble, CC BY 4.0 | |
| Aufnahme des Hubble-Weltraumteleskops | |
| AladinLite | |
| Sternbild | Walfisch |
| Position Äquinoktium: J2000.0, Epoche: J2000.0 | |
| Rektaszension | 00h 39m 08,4s[1] |
| Deklination | -14° 10′ 22″[1] |
| Erscheinungsbild | |
| Morphologischer Typ | SB(s)m? pec[1] |
| Helligkeit (visuell) | 12,6 mag[2] |
| Helligkeit (B-Band) | 13,4 mag[2] |
| Winkelausdehnung | 2,1' × 0,9'[2] |
| Positionswinkel | 178°[2] |
| Flächenhelligkeit | 13,1 mag/arcmin²[2] |
| Physikalische Daten | |
| Rotverschiebung | 0,004827 ± 0,000010[1] |
| Radialgeschwindigkeit | (1447 ± 3) km/s[1] |
| Hubbledistanz vrad / H0 | (67 ± 5) · 106 Lj (20,4 ± 1,4) Mpc [1] |
| Durchmesser | 40.000 Lj[3] |
| Geschichte | |
| Entdeckung | Ormond Stone |
| Entdeckungsdatum | 3. November 1885 |
| Katalogbezeichnungen | |
| NGC 178 • IC 39 • PGC 2349 • MCG -02-02-078 • IRAS 0366-1426 • 2MASX J00390839-1410222 • GALEXASC J003908.28-141021.8 • LDCE 41 NED001 | |
NGC 178 = IC 39 ist eine Balken-Spiralgalaxie vom Hubble-Typ SBm im Sternbild Walfisch südlich der Ekliptik Sie ist schätzungsweise 67 Millionen Lichtjahre von der Milchstraße entfernt und hat einen Durchmesser von etwa 40.000 Lj.
Im selben Himmelsareal befinden sich u. a. die Galaxien NGC 187, NGC 207, NGC 210, IC 41.
Das Objekt wurde mehrfach entdeckt; zunächst am 7. Dezember 1957 von dem irischen Astronomen R. J. Mitchell, einem Assistenten von William Parsons (als NGC 178 gelistet), später am 3. November 1885 von dem amerikanischen Astronomen Ormond Stone (auch als NGC 178 gelistet) und am 26. August 1892 durch den französischen Astronomen Stéphane Javelle wiederentdeckt (im IC-Katalog als IC 39 aufgenommen).[4]
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(c) ESA/Hubble, CC BY 4.0
A double discovery
NGC 178 may be small, but it packs quite a punch. Measuring around 40 000 light-years across, its diameter is less than half that of the Milky Way, and it is accordingly classified as a dwarf galaxy. Despite its diminutive size, NGC 178 is busy forming new stars. On average, the galaxy forms stars totalling around half the mass of the Sun per year — enough to label it a starburst galaxy.
The galaxy’s discovery is an interesting, and somewhat confusing, story. It was originally discovered by American astronomer Ormond Stone in 1885 and dubbed NGC 178, but its position in the sky was recorded incorrectly — by accident the value for the galaxy’s right ascension (which can be thought of as the celestial equivalent of terrestrial longitude) was off by a considerable amount.
In the years that followed NGC 178 was spotted again, this time by French astronomer Stéphane Javelle. As no catalogued object occupied that position in the sky, Javelle believed he had discovered a new galaxy and entered it into the expanded Index Catalogue under the name IC 39. Later, American astronomer Herbert Howe also observed the object and corrected Stone’s initial mistake. Many years later, astronomers finally noticed that NGC 178 and IC 39 were actually the same object!
This image of NGC 178 comprises data gathered by the Wide Field Planetary Camera 2 aboard the NASA/ESA Hubble Space Telescope.
Credit:
ESA/Hubble & NASA
Coordinates Position (RA): 0 39 8.28 Position (Dec): -14° 10' 31.82" Field of view: 1.84 x 1.22 arcminutes Orientation: North is 55.5° left of vertical
Colours & filters Band Wavelength Telescope Optical U 300 nm Hubble Space Telescope WFPC2 Optical U 300 nm Hubble Space Telescope WFPC2 Optical I 814 nm Hubble Space Telescope WFPC2 Optical I 814 nm Hubble Space Telescope WFPC2.