NGC 4559 explained

NGC 4559
Epoch:	J2000
Type:	SAB(rs)cd^[1]
Dist Ly:	~ 29 Mly (8.859 Mpc)
Z:	816 ± 9 km/s
Appmag V:	10.4
Size V:	10.7 × 4.4
Constellation Name:	Coma Berenices
Names:	UGC 7766, PGC 42002, Caldwell 36

NGC 4559 (also known as Caldwell 36) is an intermediate spiral galaxy with a weak inner ring structure in the constellation Coma Berenices. Distance estimates for NGC 4559 range from about 28 million light-years to 31 million light-years, averaging about 29 million light-years. It was discovered on 11 April 1785 by German-British astronomer William Herschel.^[2]

NGC 4559 is a member of the Coma I Group.^{[3] [4]}

One supernova has been recorded in NGC 4559: SN 1941A (Type II-L, mag. 13.2).^[5]

NGC 4559 is home to the luminous blue variable AT 2016blu, which experiences repeated supernova-like outbursts. First observed in January 2012, it burst out again in 2014, 2016, 2017, 2018, 2019, 2020, 2021, 2022, and 2024.^{[6] [7]}

See also

• Messier 99 – a similar spiral galaxy

Notes and References

1. Web site: NASA/IPAC Extragalactic Database . Results for NGC 4559 . 2020-12-21.
2. Web site: NGC 4559 . Seligman . Courtney . Celestial Atlas . 15 August 2024 .
3. Sandage. A.. Tammann. G.A.. 1975. Steps toward the Hubble constant. V - The Hubble constant from nearby galaxies and the regularity of the local velocity field. 1975ApJ...196..313S. The Astrophysical Journal. en. 196. 313–328. 10.1086/153413. 0004-637X. free.
4. Gregory . S.A.. Thompson. L. A.. 1977. The Coma I Galaxy Cloud . 1977ApJ...213..345G. The Astrophysical Journal. en. 213. 345–350. 10.1086/155160. 0004-637X.
5. Web site: Transient Name Server . SN 1941A . . 14 August 2024.
6. Web site: LBV 2016blu in NGC 4559. 6 July 2021. 9 August 2021. David. Bishop. rochesterastronomy.org.
7. 2212.09708 . Aghakhanloo . Mojgan . Smith . Nathan . Milne . Peter . Andrews . Jennifer E. . Van Dyk . Schuyler D. . Filippenko . Alexei V. . Jencson . Jacob E. . Lau . Ryan M. . Sand . David J. . Wyatt . Samuel . Zheng . WeiKang . Recurring outbursts of the supernova impostor AT 2016blu in NGC 4559 . Monthly Notices of the Royal Astronomical Society . 2022 . 526 . 1 . 456 . 10.1093/mnras/stad2702 . free . 2023MNRAS.526..456A .