The NGC 2841 group is a small galaxy aggregation in the constellation Ursa Major whose most prominent member is the spiral galaxy NGC 2841. The group is catalogued in several extragalactic group listings, such as the Lyon Groups of Galaxies (LGG 150) and the Nearby Galaxy Catalog (NGC 229).
Key characteristics
| Property | Details |
|---|---|
| Dominant galaxy | NGC 2841 – an SA(r)b spiral galaxy with a diameter of ~30 kpc and a distance of ~14 Mpc (≈45 million light‑years). |
| Location | Centered near right ascension 09ʰ 22ᵐ 00ˢ, declination +50° 58′ (J2000), in the region of Ursa Major. |
| Group type | Loose, low‑density galaxy group (often classified as a “single‑band” group containing a handful of members). |
| Estimated membership | Approximately 5–10 galaxies are commonly associated, including NGC 2835, NGC 2854, NGC 2855, and a few dwarf companions identified in the NASA/IPAC Extragalactic Database (NED). |
| Radial velocity | Mean heliocentric velocity of the group is ≈ 620 km s⁻¹, consistent with the velocity of NGC 2841 (≈ 638 km s⁻¹). |
| Distance | The group’s distance is taken as the distance to NGC 2841, about 14 Mpc; individual members have distance estimates within ±2 Mpc. |
| Environment | Situated on the outskirts of the Leo Spur, a filamentary structure that forms part of the Local Supercluster. The group is relatively isolated from larger clusters such as the Virgo Cluster. |
Notable members
- NGC 2841 – The principal galaxy, notable for its extensive, low‑surface‑brightness outer disk and a well‑studied H I rotation curve.
- NGC 2835 – A barred spiral (SBc) located ~ 0.8 Mpc from NGC 2841 in projection.
- NGC 2854 – An intermediate‑type spiral (SABc) lying ~ 1.2 Mpc from the group center.
- NGC 2855 – A lenticular galaxy (S0) with a faint disk, considered a probable physical member.
- Dwarf companions – Several low‑luminosity dwarf galaxies (e.g., DDO 79, UGC 05001) have been identified in the same velocity range and are thought to be gravitationally bound to the group.
Scientific relevance
The NGC 2841 group serves as a useful laboratory for studying galaxy evolution in low‑density environments. Because the dominant galaxy is massive and relatively isolated, dynamical interactions within the group are modest, allowing investigations of secular processes (e.g., bar-driven gas inflow) without strong tidal disturbances. The group's proximity also makes it accessible for detailed multi‑wavelength observations, ranging from optical imaging to radio H I mapping.
References and data sources
- NASA/IPAC Extragalactic Database (NED) – query results for NGC 2841 and surrounding galaxies.
- Lyon Groups of Galaxies (LGG) catalog, entry LGG 150.
- Tully, R. B. (1988). Nearby Galaxy Catalog. Cambridge University Press.
Note: The composition of the NGC 2841 group can vary slightly among catalogs, reflecting differences in membership criteria (e.g., radial velocity limits and projected separation). The information presented reflects the most commonly cited membership list in peer‑reviewed astronomical databases.
