SN 2004dj

{{Short description|July 2004 supernova event in the constellation Camelopardalis}}

{{Infobox supernova |

| name = SN 2004dj

| image = Supernova 2004dj.jpg

| type = II-P

| SNRtype = Nebula

| host = NGC 2403

| constellation = Camelopardalis

| epoch = J2000.0

| ra = 07^h 37^m 17.044^s

| dec = +65° 35{{prime}} 57.84{{pprime}}

| gal = ?

| discovery = 31 July 2004 18:15 UTC

| mag_v = +11.2

| distance = about 11,000,000 light-years [http://antwrp.gsfc.nasa.gov/apod/ap040907.html]

| progenitor = Unknown star in compact cluster Sandage 96

| progenitor_type = Supergiant

| b-v = Unknown

| notes = Light Curves }}

SN 2004dj was the brightest supernova since SN 1987A at the time of its discovery.{{Cn|date=March 2023}}

File:SN2004djLightCurve.png for SN 2004dj, plotted from AAVSO data]]

This Type II-P supernova was discovered by Japanese astronomer Kōichi Itagaki on 31 July 2004. At the time of its discovery, its apparent brightness was 11.2 visual magnitude; the discovery occurred after the supernova had reached its peak magnitude.{{Cite journal |last1=Nakano |first1=S. |last2=Itagaki |first2=K. |last3=Bouma |first3=R. J. |last4=Lehky |first4=M. |last5=Hornoch |first5=K. |date=2004-08-01 |title=Supernova 2004dj in NGC 2403 |url=https://ui.adsabs.harvard.edu/abs/2004IAUC.8377....1N |journal=International Astronomical Union Circular |issue=8377 |pages=1 |bibcode=2004IAUC.8377....1N |issn=0081-0304}} {{Cite journal |last1=A. J. |first1=Nayana |last2=Chandra |first2=Poonam |last3=K. Ray |first3=Alak |date=2018-08-20 |title=Long-term Behavior of a Type IIP Supernova SN 2004dj in the Radio Bands |journal=The Astrophysical Journal |volume=863 |issue=2 |pages=163 |doi=10.3847/1538-4357/aad17a |issn=1538-4357|doi-access=free |bibcode=2018ApJ...863..163N }} The supernova's progenitor is a star in a young, compact star cluster in the galaxy NGC 2403, in Camelopardalis. The cluster had been cataloged as the 96th object in a list of luminous stars and clusters by Allan Sandage in 1984; the progenitor is therefore commonly referred to as Sandage 96. This cluster is easily visible in a Kitt Peak National Observatory image and appears starlike.