Key facts
- Constellation
- Ursa Major
- Right ascension
- 08 55 34.7287
- Declination
- +58 ° 44 ′ 03.908 ″
- Distance
- 48.2 ± 3.4 Mly (14.79 ± 1.05 Mpc )
- Type
- (R)SB0^+ pec
- Size
- ~61,900 ly (18.98 kpc ) (estimated)
- Apparent size v
- 4.6′ × 2.5′
via Wikipedia infobox
~2 min read
Encyclopedic overview
NGC 2685 (also known as the Helix Galaxy) is a lenticular and polar ring Seyfert Type 2 galaxy in the constellation Ursa Major. Its velocity with respect to the cosmic microwave background is 1003 ± 9 km/s, which corresponds to a Hubble distance of 48.2 ± 3.4 Mly (14.79 ± 1.05 Mpc). Additionally, eight non-redshift measurements give a distance of 42.56 ± 3.01 Mly (13.050 ± 0.924 Mpc). It was discovered by German astronomer Wilhelm Tempel on 18 August 1882.
NGC 2685 is an object of great scientific interest, because polar-ring galaxies are very rare galaxies. They are thought to form when two galaxies gravitationally interact with each other. "The bizarre configuration could be caused by the chance capture of material from another galaxy by a disk galaxy, with the captured debris strung out in a rotating ring. Still, observed properties of NGC 2685 suggest that the rotating ring structure is remarkably old and stable."
Excerpted from Wikipedia’s “Q1050311” article, available under the CC BY-SA 4.0 licence.