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NGC 3021
NGC 3021 (right of center) as seen by the HST
Observation data (J2000 epoch)
Constellation	Leo Minor
Right ascension	09 50 57.146
Declination	33° 33′ 12.94″
Redshift	0.00514±0.000013
Heliocentric radial velocity	1,537±4 km/s
Galactocentric velocity	1,502±4 km/s
Distance	92.8 Mly (28.44 Mpc)
Apparent magnitude (V)	10.88
Apparent magnitude (B)	12.54
Absolute magnitude (V)	−21.25
Characteristics
Type	SA(rs)bc, 4.0
Apparent size (V)	1.6′ × 0.9′
Notable features	Starburst galaxy
Other designations
2MASX J09505711+3333124, NGC 3021, UGC 5280, PGC 28357

NGC 3021 is a spiral galaxy in the northern constellation of Leo Minor. It is about 93 million light-years away from Earth, and is receding with a heliocentric radial velocity of 1,537±4 km/s. This galaxy was discovered December 7, 1785 by Anglo-German astronomer William Herschel. The morphological classification of NGC 3021 is SA(rs)bc, which indicates a spiral galaxy with no central bar (SA), an incomplete inner ring structure (rs), and moderate to loosely wound spiral arms (bc).

The galaxy contains many Cepheid variable stars. These stars have been used to measure the distances of galaxies. This galaxy was also used to help refine the measurement of the Hubble constant.

Supernovae

• On November 1, 1995, S. Pesci and P. Mazza in Milan, Italy reported the discovery of a supernova in the NGC 3021 galaxy. G. M. Hurst in England confirmed the finding, estimating the magnitude at 13.2. Designated SN 1995al, it was offset 15.0″ west and 2.9″ south of the galactic nucleus. The spectrum matched a type Ia supernova and was found to be similar to SN 1981b near maximum.
• On 18 February 2023, a second supernova appeared in this galaxy: SN 2023bvj (Type II, mag. 17).

References

1. Hille, Karl (July 30, 2015). "Hubble View of a Cosmological Measuring Tape". NASA. Retrieved October 2, 2015.
2. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
3. ^ "NASA/IPAC Extragalactic Database (NED)". California Institute of Technology. Retrieved October 2, 2015.
4. ^ Tully, R. Brent; et al. (August 2016). "Cosmicflows-3". The Astronomical Journal. 152 (2): 21. arXiv:1605.01765. Bibcode:2016AJ....152...50T. doi:10.3847/0004-6256/152/2/50. S2CID 250737862. 50.
5. ^ Anupama, G. C. (November 1997). "Optical Spectra of Recent Supernovae of Type Ia: SN1995AL, SN1997Y, SN1997BP". Astronomical Journal. 114: 2054. Bibcode:1997AJ....114.2054A. doi:10.1086/118625.
6. "NGC 3021". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-12-17.
7. Seligman, C. "NGC Objects: NGC 3000 - 3049". Celestial Atlas. Retrieved 2021-12-17.
8. information@eso.org. "A cosmological measuring tape". www.spacetelescope.org. Retrieved 2023-11-26.
9. Pesci, S.; et al. (November 1995). Green, D. W. E. (ed.). "Supernova 1995al in NGC 3021". IAU Circular. 6255 (1): 1. Bibcode:1995IAUC.6255....1P.
10. Wei, J. -Y.; et al. (November 1995). Green, D. W. E. (ed.). "Supernova 1995al in NGC 3021". IAU Circular. 6256 (1): 1. Bibcode:1995IAUC.6256....1W.
11. "SN 2023bvj | Transient Name Server". www.wis-tns.org. Retrieved 2023-07-06.

External links

• [REDACTED] Media related to NGC 3021 at Wikimedia Commons

v t e Constellation of Leo Minor
List of stars in Leo Minor Leo Minor in Chinese astronomy
Stars	Bayer β Flamsteed 7 8 9 10 11 13 16 17 19 20 21 22 23 24 26 27 28 29 30 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 (Praecipua) 48 50 51 Variable R RW RY RZ SX VW YZ AS HR 3979 3993 HD 82886 (Illyrian) 87883 93521 Other NGC 3382
Exoplanets HD 87883 b
Galaxies	NGC 2859 3003 3021 3245 3254 3294 3344 3395 3396 3414 3430 3432 3486 3504 Other 3C 223 3C 236 AGC 198691 Arp 107 IC 2497
Category

• Unbarred spiral galaxies
• Leo Minor
• NGC objects
• UGC objects
• Principal Galaxies Catalogue objects