SN 2017cfd: A Normal Type Ia Supernova Discovered Very Young

Xuhui Han, Wei Kang Zheng, Benjamin E. Stahl, Jamison Burke, Jozsef Vinko, Thomas de Jaeger, Iair Arcavi, Thomas G. Brink, Borbala Cseh, Daichi Hiramatsu, Griffin Hosseinzadeh, D. Andrew Howell, Bernadett Ignacz, Reka Konyves-Toth, Mate Krezinger, Curtis Mccully, Andras Ordasi, Dora Pinter, Krisztian Sarneczky, Robert SzakatsKevin Tang, Krisztian Vida, Jing Wang, Jianyan Wei, J. Craig Wheeler, Liping Xin, Alexei V. Filippenko

Research output: Contribution to journalArticlepeer-review


The Type Ia supernova (SN Ia) 2017cfd in IC 0511 (redshift z=0.01209\pm 0.00016) was discovered by the Lick Observatory Supernova Search 1.6 ± 0.7 day after the fitted first-light time (15.2 days before B-band maximum brightness). Photometric and spectroscopic follow-up observations show that SN 2017cfd is a typical, normal SN Ia with a peak luminosity MB ≈-19.2 0.2 mag, Δm 15(B) = 1.16 mag, and reached a B-band maximum ∼16.8 days after the first light. We estimate there to be moderately strong host-galaxy extinction (A V = 0.39 ± 0.03 mag) based on MLCS2k2 fitting. The spectrum reveals a Si ii λ6355 velocity of ∼11,200 km s-1 at peak brightness. SN 2017cfd was discovered very young, with multiband data taken starting 2 days after the first light, making it a valuable complement to the currently small sample (fewer than a dozen) of SNe Ia with color data at such early times. We find that its intrinsic early-time B-V)0 color evolution belongs to the "blue" population rather than to the distinct "red" population. Using the photometry, we constrain the companion-star radius to be ≲2.5 R with the Kasen model, thus ruling out a red-giant companion.

Original languageEnglish
Article number142
JournalAstrophysical Journal
Issue number2
StatePublished - 1 Apr 2020


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