NGC 3110
A triple-catalogued active spiral galaxy in Sextans.
NGC 3110 is an active spiral galaxy located in the constellation Sextans, south of the celestial equator. It is notable for being recorded in the NGC catalogue under three separate designations—NGC 3110, NGC 3122, and NGC 3518—due to independent observations by multiple astronomers. The galaxy is estimated to be 218 million light-years from the Milky Way and has a diameter of about 100,000 light-years.
Quick Facts
- Constellation Name
- Sextans
- Ra
- 10 · 04 · 02.0
- Dec
- −06 · 28 · 29
- Z
- 0.017070
- H Radial V
- 5073.9 km/s
- Appmag V
- 13.5
- Epoch
- J2000
- Names
- NGC 3110, NGC 3122, NGC 3518, PGC 29192, MCG-01-26-014, IRAS F10015-0614
Facts from the source article.
Lore & Background
NGC 3110 was first observed by William Herschel on March 5, 1785, though that observation was later catalogued as NGC 3122. The French astronomer Édouard Stephan independently observed the same galaxy on February 17, 1884, and his entry became NGC 3110. American astronomer Ormond Stone also recorded it on December 31, 1885, resulting in the designation NGC 3518. This galaxy forms a gravitationally bound pair with PGC 29184, and the galaxy IC 589 lies in the same area of the sky.
The galaxy contains extensive star-forming regions and is classified as a bright infrared galaxy (LIRG). It has a broad HI line and regions of ionized hydrogen. Three non-redshift measurements give a distance of approximately 177 million light-years (54.300 ± 1.375 Mpc), which differs from the Hubble distance values.
Reader's Guide
NGC 3110 holds significance as an example of how early astronomical catalogues could record the same object under multiple entries due to independent discoveries. Its triple listing—as NGC 3110, NGC 3122, and NGC 3518—reflects the observational work of Herschel, Stephan, and Stone across different decades. The galaxy's status as a bright infrared galaxy (LIRG) and its broad HI line indicate active star formation and energetic processes. Its gravitational pairing with PGC 29184 adds to its interest as part of an interacting system. The discrepancy between non-redshift distance measurements and Hubble distance values highlights ongoing challenges in accurately determining extragalactic distances. For astronomers studying spiral galaxy structure, star-forming regions, and galaxy interactions, NGC 3110 provides a useful case study of a moderately distant, active system in the constellation Sextans.
Did You Know?
- NGC 3110 is also catalogued as NGC 3122 and NGC 3518 due to separate observations by three astronomers.
- It forms a gravitationally bound pair with the galaxy PGC 29184.
- Three non-redshift measurements give a distance of about 177 million light-years, differing from Hubble distance values.
- The galaxy contains extensive Hubble-type Sb star-forming regions and is a bright infrared galaxy (LIRG).
Frequently Asked Questions
What is NGC 3110?
NGC 3110 is a spiral galaxy classified as Hubble-type Sb, meaning it has a distinct central bulge wrapped by well-organized spiral arms. It is labelled 'active' because of its energetic emission properties, including strong infrared output and broad hydrogen signals.
Why does NGC 3110 carry three different catalog numbers?
Several astronomers independently spotted the galaxy at different times, and each sighting was logged as its own entry before cross-referencing revealed they were the same object. As a result, the same galaxy is listed under NGC 3110, NGC 3122, and NGC 3518.
Where in the sky can I find NGC 3110?
It resides in the constellation Sextans, which sits below the celestial equator, making it most accessible from southern-hemisphere observing sites. The galaxy is roughly 218 million light-years from the Milky Way.
What does 'active' actually mean for NGC 3110?
The designation reflects its unusually high infrared luminosity—qualifying it as a Luminous Infrared Galaxy—along with a broad neutral-hydrogen emission line and patches of ionized gas. Together these features point to vigorous star formation or other energetic processes occurring within its disk.
How big is NGC 3110 compared to the Milky Way?
Its disk stretches roughly 100,000 light-years across, placing it in the same size range as our own galaxy. At that scale, it would present a substantial angular patch of sky if viewed from a great distance.
More in NGC Objects, Part 5 1-24
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