NGC 3184
Template:Short description Template:Infobox Galaxy
NGC 3184, also known as The Little Pinwheel Galaxy, is an unbarred spiral galaxy approximately 40 million light-years away<ref name=ned-dist/> in the constellation Ursa Major. Its name comes from its resemblance to the Pinwheel Galaxy. It was discovered by German-British astronomer William Herschel on 18 March 1787.<ref name="seg">Template:Cite web</ref> It has two HII regions named NGC 3180<ref name=ned-ngc3180>Template:Cite web</ref> and NGC 3181.<ref name=ned-ngc3181>Template:Cite web</ref>
NGC 3184 houses a high abundance of heavy elements. The blue color of its spiral arms comes mostly from relatively few bright young blue stars. The bright stars that highlight the arms were created in huge density waves that circle the center.
Structure
NGC 3184 has two prominent spiral arms. They have constant pitch angles, which makes them both symmetrical.<ref name="structure">Template:Cite journal</ref>
Supernovae and astronomical transients
Six supernovae and astronomical transients have been observed in NGC 3184:
- SN 1921B (type unknown, mag. 13.5) was discovered by Fritz Zwicky on 6 April 1921.<ref>Template:Cite web</ref>
- SN 1921C (type unknown, mag. 11) was discovered on 5 December 1921.<ref>Template:Cite web</ref>
- SN 1937F (type unknown, mag. 16.1) was discovered by Rebecca Jones on 9 December 1937.<ref>Template:Cite journal</ref><ref>Template:Cite web</ref> [Note: many sources incorrectly list the discoverer as Fritz Zwicky.]
- SN 1999gi (Type II, mag. 14.5) was discovered by Reiki Kushida on 9 December 1999.<ref>Template:Cite web</ref><ref name="sn1999gi">Template:Cite journal</ref><ref name="1999gi">Template:Cite web</ref>
- SN 2010dn (Type ILRT, mag. 17.5) was discovered by Kōichi Itagaki on 31 May 2010.<ref>Template:Cite journal</ref><ref>Template:Cite web</ref>
- SN 2016bkv (Type II, mag. 17.2) was discovered by Kōichi Itagaki on 21 March 2016.<ref>Template:Cite web</ref>
SN 2010dn
On May 31, 2010, Kōichi Itagaki detected a magnitude 17 optical transient 33" east and 61" north of the center of NGC 3184 at coordinates 10 18 19.89 +41 26 28.8.<ref name="supernovae.net">Template:Cite web</ref> Designated SN 2010dn, this event was initially thought to be an outbursting luminous blue variable (LBV) star,<ref name=Smith2010>Template:Cite journal</ref> but later analysis categorized it as an intermediate-luminosity red transient (ILRT), also known as a luminous red nova.<ref>Template:Cite journal</ref><ref>Template:Cite web</ref> Archival Hubble and Spitzer images of NGC 3184 seem to show no progenitor for optical transient SN 2010dn.<ref name=atel2655>Template:Cite web</ref> SN 2010dn is just like SN 2008S and NGC 300-OT.<ref name=Smith2010/> On day 2, SN 2010dn had an unfiltered magnitude of 17.1, corresponding to a peak absolute magnitude of roughly -13.3.<ref name=Smith2010/>
| Name | apmag | type |
|---|---|---|
| SN 1921B | 13.5 | ? |
| SN 1921C | 11.0 | ? |
| SN 1937F | 13.5 | ? |
| SN 1999gi | 14.0 | II |
| SN 2010dn | 17.2 | ILRT |
| SN 2016bkv | 17.2 | II |
| Galaxy | number | Declination |
|---|---|---|
| Arp 299 (NGC 3690 + IC 694) | 14 | +58 |
| NGC 6946 (Fireworks) | 10 | +60 |
| Messier 61 | 8 | +04 |
| Messier 100 | 7 | +15 |
| NGC 3184 | 6 | +41 |
| Messier 83 (Southern Pinwheel) | 6 | −29 |
| NGC 2207 and IC 2163 | 6 | −21 |
| NGC 2276 | 6 | +85 |
| Messier 66 | 5 | +12 |
| Messier 101 (Pinwheel) | 5 | +54 |
| NGC 309 | 5 | −09 |
See also
References
External links
- Template:APOD
- Spiral Galaxy NGC 3184 & Supernova 1999gi (20-inch F/8.1 Ritchey Chretien Cassegrain)
- Supernova 1999gi in NGC 3184 (supernovae.net)
- Discovery image of SN2010dnTemplate:Dead link (2010-05-31 mag 17.5) / Wikisky DSS2 and SDSS zoom-in of the same region
