# SN 2020tlf

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Type II supernova that occurred 120 million light years away in the galaxy NGC 5731

SN 2020tlf Light curves for SN 2020tlf in four photometric bands, plotted from data published by Jacobson-Galán et al. (2022)[1] Event type Type IIn Constellation Boötes Right ascension 14h 40m 10.03s[1] Declination 42° 46′ 39.45″[1] Epoch J2000 Distance 36.8±1.29 million pc[1] Redshift 0.008463±0.0003[1] Host NGC 5731 Progenitor type Red supergiant Peak apparent magnitude 15.89[1] [edit on Wikidata]

**SN 2020tlf** was a [Type II supernova](/source/Type_II_supernova) that occurred 120 million [light years](/source/Light_year) away in the galaxy [NGC 5731](https://en.wikipedia.org/w/index.php?title=NGC_5731&action=edit&redlink=1). The supernova marked the first time that a [red supergiant](/source/Red_supergiant) star had been observed before, during, and after the event,[2][1] being observed up to 130 days before.[2] The progenitor star was between 10 and 12 [solar masses](/source/Solar_masses).

## Observations

The star was first observed by the [Pan-STARRS](/source/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.[3][4] Observations were also made throughout the [electromagnetic spectrum](/source/Electromagnetic_spectrum), such as in the X-ray, ultraviolet, infrared and radio wave spectrums.[1]

## References

1. ^ [***a***](#cite_ref-ApJ_1-0) [***b***](#cite_ref-ApJ_1-1) [***c***](#cite_ref-ApJ_1-2) [***d***](#cite_ref-ApJ_1-3) [***e***](#cite_ref-ApJ_1-4) [***f***](#cite_ref-ApJ_1-5) [***g***](#cite_ref-ApJ_1-6) [***h***](#cite_ref-ApJ_1-7) Jacobson-Galán, W. V.; Dessart, L.; Jones, D. O.; [Margutti, R.](/source/Raffaella_Margutti); Coppejans, D. L.; Dimitriadis, G.; Foley, R. J.; Kilpatrick, C. D.; Matthews, D. J.; Rest, S.; Terreran, G.; Aleo, P. D.; Auchettl, K.; Blanchard, P. K.; Coulter, D. A.; Davis, K. W.; de Boer, T. J. L.; DeMarchi, L.; Drout, M. R.; Earl, N.; Gagliano, A.; Gall, C.; Hjorth, J.; Huber, M. E.; Ibik, A. L.; Milisavljevic, D.; Pan, Y. C.; Rest, A.; Ridden-Harper, R.; Rojas-Bravo, C.; Siebert, M. R.; Smith, K. W.; Taggart, K.; Tinyanont, S.; Wang, Q.; Zenati, Y. (January 6, 2022). ["Final Moments. I. Precursor Emission, Envelope Inflation, and Enhanced Mass Loss Preceding the Luminous Type II Supernova 2020tlf"](https://doi.org/10.3847%2F1538-4357%2Fac3f3a). *The Astrophysical Journal*. **924** (1): 15. [arXiv](/source/ArXiv_(identifier)):[2109.12136](https://arxiv.org/abs/2109.12136). [Bibcode](/source/Bibcode_(identifier)):[2022ApJ...924...15J](https://ui.adsabs.harvard.edu/abs/2022ApJ...924...15J). [doi](/source/Doi_(identifier)):[10.3847/1538-4357/ac3f3a](https://doi.org/10.3847%2F1538-4357%2Fac3f3a). [S2CID](/source/S2CID_(identifier)) [237940678](https://api.semanticscholar.org/CorpusID:237940678).

1. ^ [***a***](#cite_ref-Gough_2-0) [***b***](#cite_ref-Gough_2-1) Gough, Evan (February 7, 2022). ["Astronomers Watch a Star Die and Then Explode as a Supernova – For the Very First Time"](https://scitechdaily.com/astronomers-watch-a-star-die-and-then-explode-as-a-supernova-for-the-very-first-time/). SciTechDaily. [Archived](https://ghostarchive.org/archive/20220314/https://scitechdaily.com/astronomers-watch-a-star-die-and-then-explode-as-a-supernova-for-the-very-first-time/) from the original on 2022-03-14. Retrieved February 14, 2022.

1. **[^](#cite_ref-3)** Anderson, Paul (January 14, 2022). ["Dying star's explosive end seen by astronomers"](https://earthsky.org/space/dying-stars-explosive-end-supernova-sn-2020tlf/). EarthSky. [Archived](https://ghostarchive.org/archive/20220314/https://earthsky.org/space/dying-stars-explosive-end-supernova-sn-2020tlf/) from the original on 2022-03-14. Retrieved February 14, 2022.

1. **[^](#cite_ref-4)** Specktor, Brandon (January 11, 2022). ["Scientists watched a star explode in real time for the first time ever"](https://www.livescience.com/first-supernova-real-time-observations). [Live Science](/source/Live_Science). [Archived](https://ghostarchive.org/archive/20220314/https://www.livescience.com/first-supernova-real-time-observations) from the original on 2022-03-14. Retrieved February 14, 2022.

v t e Constellation of Boötes Boötes in Chinese astronomy Boötes Void List of stars in Boötes Stars Bayer α (Arcturus) β (Nekkar) γ (Seginus) δ (Qigong) ε (Izar, Pulcherrima) ζ η (Muphrid) θ ι κ λ (Xuange) μ1 (Alkalurops) μ2 ν1 ν2 ξ ο π ρ (Kalasungsang) σ (Genghe) τ (Tepiamenit) υ φ χ ψ ω Flamsteed 1 2 3 6 (e) 7 9 10 11 12 (d) 13 14 15 18 20 22 (f) 24 (g) 26 31 32 33 34 (Alrumh) 38 (Merga) 39 40 44 (Quadrans) 45 (c) 46 (b) 47 (k) 50 Variable R S T RX ZZ AB BL BP BX BY CE CH CI CN CP CR CX CY (101 Vir) DE EK HN HP HD 118508 118889 122563 125040 125351 (A) 125658 126128 126129 126141 126200 126271 127304 127334 127726 128093 128198 129132 129357 130084 130603 130917 131040 131473 131496 (Arcalís) 132029 132406 132563 134064 134335 135438 135530 135944 141399 Other 2MASS J15031961+2525196 CFBDSIR 1458+10 Gliese 526 HAT-P-4 LHS 2924 PSR J1544+4937 SDSS J1416+1348 SDSS J1433+1011 TVLM 513-46546 WASP-14 WD 1425+540 ZTF J153932.16+502738.8 Exoplanets HAT-P-4b HD 128311 b c HD 132406 b HD 136418 b (Awasis) τ Boötis b TOI-1853 b WASP-14b Star clusters NGC 5466 Galaxies NGC 5008 5248 5251 5416 5490 5500 5504 5508 5514 5523 5529 5532 5533 5535 5539 5541 5544 5545 5548 5557 5559 5562 5579 5582 5591 5601 5603 5609 5613 5614 5615 5624 5629 5630 5641 5642 5653 5665 5676 5681 5682 5683 5698 5714 5722 5752 5753 5754 5755 5772 5778 5784 5790 5820 5821 5829 5837 5857 5875 5876 5886 5888 5896 5929 5930 5966 Numbered I II III Other 3C 295 3C 299 3C 300 3C 303 3C 315 4C 19.44 4C +26.42 7C 1354+2552 Abell 2009 BCG Arp 302 B2 1420+32 B2 1441+26 CEERS-2112 CEERS-93316 CEERS2-588 CLASS B1359+154 Cloverleaf quasar DDO 190 EGS-zs8-1 EGS-z11-R0 EGSY8p7 H1426+428 IC 4397 IC 4461 IC 4462 IC 4481 IC 4516 IRAS 13349+2438 IRAS 14394+5332 IRAS 15206+3342 LEDA 2108986 MACS 1423-z7p64 MACS J1447.4+0827 BCG Maisie's Galaxy Markarian 463 Markarian 471 Markarian 478 MS 1455.0+2232 BCG MS 1512-cB58 NVSS J141343+433945 OQ 172 OQ 530 PG 1411+442 PG 1543+489 PGC 93125 PGC 1470080 PKS 1345+125 PKS 1413+135 QSO B1422+202 RBS 1467 RGZ J145001.5+144747 RGZ J145039.8+441829 SBS 1415+437 SDSS J135646.10+102609.0 SDSS J1430+2303 Teacup galaxy UGC 8669 UGC 9128 UGC 9425 UGC 9684 UGC 9796 ULAS J1342+0928 VV 191 Galaxy clusters Abell 1795 Abell 1991 BoRG-58 IDCS J1426.5+3508 Astronomical events GRB 990123 GRB 080319B SCP 06F6 SN 2003fg SN 2005bc SN 2020tlf Category

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