NGC 6861
| Galaxie NGC 6861 / IC 4949 | |
|---|---|
 (c) ESA/Hubble, CC BY 4.0 | |
| NGC 6861[1] (Hubble-Weltraumteleskop) | |
| AladinLite | |
| Sternbild | Teleskop |
| Position Äquinoktium: J2000.0, Epoche: J2000.0 | |
| Rektaszension | 20h 07m 19,5s[2] |
| Deklination | -48° 22′ 13″[2] |
| Erscheinungsbild | |
| Morphologischer Typ | SA(s)0-:[2] |
| Helligkeit (visuell) | 11,1 mag[3] |
| Helligkeit (B-Band) | 12,1 mag[3] |
| Winkelausdehnung | 3,′0 × 2,′0[3] |
| Positionswinkel | 140°[3] |
| Flächenhelligkeit | 13,1 mag/arcmin²[3] |
| Physikalische Daten | |
| Zugehörigkeit | Telescopium-Gruppe SSRS Gruppe 28 NGC 6868-Gruppe LGG 430[2][4] |
| Rotverschiebung | 0,009437 ± 0,000057[2] |
| Radialgeschwindigkeit | (2829 ± 17) km/s[2] |
| Hubbledistanz vrad / H0 | (125 ± 9) · 106 Lj (38,4 ± 2,7) Mpc [2] |
| Geschichte | |
| Entdeckung | James Dunlop |
| Entdeckungsdatum | 30. Juli 1826 |
| Katalogbezeichnungen | |
| NGC 6861 • IC 4949 • PGC 64136 • ESO 233-32 • IRAS 20037-4830 • 2MASX J20071948-4822129 • SGC 200341-4830.9 • GALEXASC J200719.45-482212.6 • LDCE 1384 NED002 | |
NGC 6861 = IC 4949 ist eine elliptische Galaxie vom Hubble-Typ E/S0[3] im Sternbild Teleskop am Südsternhimmel. Sie ist rund 125 Millionen Lichtjahre von der Milchstraße entfernt und hat einen Durchmesser von etwa 110.000 Lichtjahren.
Im selben Himmelsareal befinden sich u. a. die Galaxien NGC 6851, NGC 6868, NGC 6870, IC 4943.
Das Objekt wurde am 30. Juli 1826 von James Dunlop[5] mit Hilfe eines 9-Zoll-Teleskops entdeckt. „Wiederentdeckt“ am 8. Juli 1897 von Lewis Swift (als IC-Objekt eingetragen als IC 4949).
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(c) ESA/Hubble, CC BY 4.0
The third way of galaxies
The third way of galaxies Click to Enlarge
The subject of this image is NGC 6861, a galaxy discovered in 1826 by the Scottish astronomer James Dunlop. Almost two centuries later we now know that NGC 6861 is the second brightest member of a group of at least a dozen galaxies called the Telescopium Group — otherwise known as the NGC 6868 Group — in the small constellation of Telescopium (The Telescope).
This NASA/ESA Hubble Space Telescope view shows some important details of NGC 6861. One of the most prominent features is the disc of dark bands circling the centre of the galaxy. These dust lanes are a result of large clouds of dust particles obscuring the light emitted by the stars behind them.
Dust lanes are very useful for working out whether we are seeing the galaxy disc edge-on, face-on or, as is the case for NGC 6861, somewhat in the middle. Dust lanes like these are typical of a spiral galaxy. The dust lanes are embedded in a white oval shape, which is made up of huge numbers of stars orbiting the centre of the galaxy. This oval is, rather puzzlingly, typical of an elliptical galaxy.
So which is it — spiral or elliptical? The answer is neither! NGC 6861 does not belong to either the spiral or the elliptical family of galaxies. It is a lenticular galaxy, a family which has features of both spirals and ellipticals.
The relationships between these three kinds of galaxies are not yet well understood. A lenticular galaxy could be a faded spiral that has run out of gas and lost its arms, or the result of two galaxies merging. Being part of a group increases the chances for galactic mergers, so this could be the case for NGC 6861.
A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Josh Barrington.
Credit:
ESA/Hubble & NASA Acknowledgement: J. Barrington
About the Object
Name: NGC 6861
Type: • Local Universe : Galaxy : Type : Lenticular
• X - Galaxies Images/Videos
Constellation: Telescopium
Colours & filters Band Wavelength Telescope
Optical 555 nm Hubble Space Telescope ACS
Infrared 814 nm Hubble Space Telescope ACS
.