SN 2020tlf

{{Short description|Type II supernova that occurred 120 million light years away in the galaxy NGC 5731}} {{Infobox astronomical event |name = SN 2020tlf |image = SN2020tlfLightCurve.png |image_size = |caption = [[Light curve]]s for SN 2020tlf in four [[Photometric_system#Photometric_letters|photometric bands]], plotted from data published by Jacobson-Galán ''et al.'' (2022)<ref name=ApJ/> |alt = |names = |event_type = Type IIn |class = |start_time = |duration = |detected_by = |constellation = [[Boötes]] |ra = {{RA|14|40|10.03}}<ref name=ApJ/> |dec = {{DEC|42|46|39.45}}<ref name=ApJ/> |epoch = [[J2000]] |gal = |distance = {{val|36.8|1.29}} million [[parsec|pc]]<ref name=ApJ/> |redshift = {{val|0.008463|0.0003}}<ref name=ApJ/> |source = |remnant = |host = [[NGC 5731]] |progenitor = |progenitor_type = [[Red supergiant]] |b-v = |notes = |peak = 15.89<ref name=ApJ/> |energy = |website = |predecessor = |successor = |commons = |embedded = }}

'''SN 2020tlf''' was a [[Type II supernova]] that occurred 120 million [[light year]]s away in the galaxy [[NGC 5731]]. The supernova marked the first time that a [[red supergiant]] star had been observed before, during, and after the event,<ref name=Gough>{{cite web|last=Gough|first=Evan|title=Astronomers Watch a Star Die and Then Explode as a Supernova – For the Very First Time|url=https://scitechdaily.com/astronomers-watch-a-star-die-and-then-explode-as-a-supernova-for-the-very-first-time/ |archive-url=https://ghostarchive.org/archive/20220314/https://scitechdaily.com/astronomers-watch-a-star-die-and-then-explode-as-a-supernova-for-the-very-first-time/ |archive-date=2022-03-14 |url-status=live|publisher=SciTechDaily|date=February 7, 2022|accessdate=February 14, 2022}}{{cbignore}}</ref><ref name=ApJ>{{cite journal|last1=Jacobson-Galán|first1=W. V.|last2=Dessart|first2=L.|last3=Jones|first3=D. O.|last4=Margutti|first4=R.|author4-link=Raffaella Margutti|last5=Coppejans|first5=D. L.|last6=Dimitriadis|first6=G.|last7=Foley|first7=R. J.|last8=Kilpatrick|first8=C. D.|last9=Matthews|first9=D. J.|last10=Rest|first10=S.|last11=Terreran|first11=G.|last12=Aleo|first12=P. D.|last13=Auchettl|first13=K.|last14=Blanchard|first14=P. K.|last15=Coulter|first15=D. A.|last16=Davis|first16=K. W.|last17=de Boer|first17=T. J. L.|last18=DeMarchi|first18=L.|last19=Drout|first19=M. R.|last20=Earl|first20=N.|last21=Gagliano|first21=A.|last22=Gall|first22=C.|last23=Hjorth|first23=J.|last24=Huber|first24=M. E.|last25=Ibik|first25=A. L.|last26=Milisavljevic|first26=D.|last27=Pan|first27=Y. C.|last28=Rest|first28=A.|last29=Ridden-Harper|first29=R.|last30=Rojas-Bravo|first30=C.|last31=Siebert|first31=M. R.|last32=Smith|first32=K. W.|last33=Taggart|first33=K.|last34=Tinyanont|first34=S.|last35=Wang|first35=Q.|last36=Zenati|first36=Y.|date=January 6, 2022|title=Final Moments. I. Precursor Emission, Envelope Inflation, and Enhanced Mass Loss Preceding the Luminous Type II Supernova 2020tlf|journal=The Astrophysical Journal|volume=924|issue=1|page=15|doi=10.3847/1538-4357/ac3f3a|arxiv=2109.12136|bibcode=2022ApJ...924...15J|s2cid=237940678 |doi-access=free }}</ref> being observed up to 130 days before.<ref name=Gough/> The progenitor star was between 10 and 12 [[solar masses]].

==Observations== The star was first observed by the [[Pan-STARRS]] telescope in the summer of 2020, with other telescopes such as ATLAS also observing it. It was initially believed that red supergiants were quiet before their demise; however, SN 2020tlf was observed emitting bright, intense radiation and ejecting massive amounts of gaseous material.<ref>{{cite web|last=Anderson|first=Paul|title=Dying star's explosive end seen by astronomers|url=https://earthsky.org/space/dying-stars-explosive-end-supernova-sn-2020tlf/ |archive-url=https://ghostarchive.org/archive/20220314/https://earthsky.org/space/dying-stars-explosive-end-supernova-sn-2020tlf/ |archive-date=2022-03-14 |url-status=live|publisher=EarthSky|date=January 14, 2022|accessdate=February 14, 2022}}{{cbignore}}</ref><ref>{{cite web|last=Specktor|first=Brandon|title=Scientists watched a star explode in real time for the first time ever|url=https://www.livescience.com/first-supernova-real-time-observations |archive-url=https://ghostarchive.org/archive/20220314/https://www.livescience.com/first-supernova-real-time-observations |archive-date=2022-03-14 |url-status=live|publisher=[[Live Science]]|date=January 11, 2022|accessdate=February 14, 2022}}{{cbignore}}</ref> Observations were also made throughout the [[electromagnetic spectrum]], such as in the X-ray, ultraviolet, infrared and radio wave spectrums.<ref name=ApJ/>

==References== {{reflist}}

[[Category:Supernovae]] [[Category:Astronomical objects discovered in 2020]] [[Category:Boötes]]