NGC 491

NGC 491
NGC 491 imaged by the Hubble Space Telescope, showing its spiral arms
Observation data (J2000 epoch)
ConstellationSculptor
Right ascension01h 21m 20.4504s[1]
Declination−34° 03′ 48.096″[1]
Redshift0.012902±0.0000330[1]
Heliocentric radial velocity3,868±10 km/s[1]
Distance203.09 ± 7.02 Mly (62.267 ± 2.152 Mpc)[1]
Apparent magnitude (V)13.21[1]
Characteristics
TypeSB(rs)b[1]
Size~91,900 ly (28.17 kpc) (estimated)[1]
Apparent size (V)1.4′ × 1.0′[1]
Other designations
ESO 352- G 053, GC 279, IRAS 01190-3419, MCG -06-04-011, PGC 4914[1]

NGC 491 is a barred spiral galaxy in the constellation Sculptor.[2][1] Its velocity with respect to the cosmic microwave background is 3,635±19 km/s, which corresponds to a Hubble distance of 174.9 ± 12.3 Mly (53.62 ± 3.77 Mpc).[1] However, nine non-redshift measurements give a farther mean distance of 203.09 ± 7.02 Mly (62.267 ± 2.152 Mpc).[3] It was discovered by British astronomer John Herschel on 25 September 1834.[4]

NGC 491 is a Seyfert II galaxy, i.e. it has a quasar-like nucleus with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable.[5]

Supernova

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One supernova has been observed in NGC 491: SN 2025yjt (Type II, mag. 17.827) was discovered by ATLAS on 24 September 2025.[6]

See also

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References

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  1. ^ a b c d e f g h i j k l "Results for object NGC 0491". NASA/IPAC Extragalactic Database. NASA and Caltech. Retrieved 2017-06-04.
  2. ^ Rojas, Sebastián García. "Galaxy NGC 491 - Galaxy in Sculptor Constellation · Deep Sky Objects Browser". DSO Browser. Archived from the original on 2017-10-02. Retrieved 2017-06-04.
  3. ^ "Distance Results for NGC 0491". NASA/IPAC Extragalactic Database. NASA. Retrieved 25 September 2025.
  4. ^ "New General Catalog Objects: NGC 450 - 499". cseligman.com. Retrieved 2017-06-04.
  5. ^ "NGC 491". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 25 September 2025.
  6. ^ "SN 2025yjt". Transient Name Server. IAU. Retrieved 25 September 2025.
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