NGC 3489
A lenticular galaxy with a weak bar and active nucleus.
NGC 3489 is a lenticular galaxy in the constellation Leo, located about 30 million light years from Earth. It is notable for its weak bar, small bulge, and outer ring structure, as well as its active galactic nucleus, which has been classified as either a type 2 Seyfert galaxy or a transition object.
Quick Facts
- Epoch
- J2000
- Ra
- 11 · 00 · 18.6
- Dec
- +13 · 54 · 04
- Dist Ly
- 29 ± 8.4 Mly (8.9 ± 2.6 Mpc)
- Z
- 0.002258 ± 0.000006
- H Radial V
- 677 ± 2 km/s
- Appmag V
- 10.2
- Constellation Name
- Leo
- Names
- UGC 6082, CGCG 066-084, MCG +02-28-039, PGC 33160
Facts from the source article.
Lore & Background
NGC 3489 was discovered by William Herschel on April 8, 1784. It is a member of the Leo Group. The galaxy has a weak bar seen along the minor axis and a small bulge. Its stellar population shows an age gradient, with younger stars closer to the core. Observations in H-beta reveal a peak in the central arcsecond, indicating younger stars at the core with an estimated age of about 1.7 billion years. Although currently considered a post-starburst galaxy, molecular gas remains in the nucleus that could lead to star formation, though its mass is less than that in actively star-forming galaxies. Dust with an open spiral pattern has been observed in the nuclear region, and the galaxy possesses an outer ring structure with a diameter of 1.54 arcminutes along the major axis.
Reader's Guide
NGC 3489 hosts an active galactic nucleus, categorized based on its spectrum as a type 2 Seyfert galaxy or, based on nuclear [O I] emission strength lying between that of H II nuclei and LINER, as a transition object. This transition emission may be attributed to post-AGB stars in the core. A supermassive black hole accreting material at the center is believed to drive the nuclear activity. The black hole's mass has been estimated based on velocity dispersion. The galaxy's post-starburst status, combined with residual molecular gas and a young stellar population at the core, makes it a valuable object for studying the transition between active star formation and quiescence, as well as the interplay between black hole accretion and stellar evolution in a lenticular galaxy within the Leo Group.
Did You Know?
- NGC 3489 is about 30,000 light years across.
- The central arcsecond shows a peak in H-beta, indicating younger stars about 1.7 billion years old.
Frequently Asked Questions
What kind of object is NGC 3489?
NGC 3489 is a lenticular galaxy roughly 30,000 light years across, sitting about 30 million light years from Earth. It was first catalogued by William Herschel on April 8, 1784.
Where can I find NGC 3489 in the night sky?
Look toward the constellation Leo to locate it, at a distance of approximately 30 million light years. Its position makes it a moderately distant deep-sky target for observers.
What makes NGC 3489 stand out among other lenticular galaxies?
It displays a faint central bar, a modest bulge, and a distinctive outer ring structure that give it a unique morphology. On top of that, it hosts an active galactic nucleus at its core.
What type of active nucleus does NGC 3489 have?
Its central engine is generally classified as a type 2 Seyfert galaxy, though some researchers treat it as a transitional object between Seyfert categories. Either way, the active core is partially obscured from our viewing angle.
Who discovered NGC 3489 and when was it found?
William Herschel identified the galaxy on April 8, 1784, during his systematic survey of the heavens. It has retained its NGC catalogue number ever since being entered into the New General Catalogue.
More in NGC Objects, Part 6 1-24
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