- Main
K2 Observations of SN 2018oh Reveal a Two-component Rising Light Curve for a Type Ia Supernova
- Dimitriadis, G;
- Foley, RJ;
- Rest, A;
- Kasen, D;
- Piro, AL;
- Polin, A;
- Jones, DO;
- Villar, A;
- Narayan, G;
- Coulter, DA;
- Kilpatrick, CD;
- Pan, Y-C;
- Rojas-Bravo, C;
- Fox, OD;
- Jha, SW;
- Nugent, PE;
- Riess, AG;
- Scolnic, D;
- Drout, MR;
- Barentsen, G;
- Dotson, J;
- Gully-Santiago, M;
- Hedges, C;
- Cody, AM;
- Barclay, T;
- Howell, S;
- Garnavich, P;
- Tucker, BE;
- Shaya, E;
- Mushotzky, R;
- Olling, RP;
- Margheim, S;
- Zenteno, A;
- Coughlin, J;
- Van Cleve, JE;
- de Miranda Cardoso, J Vinícius;
- Larson, KA;
- McCalmont-Everton, KM;
- Peterson, CA;
- Ross, SE;
- Reedy, LH;
- Osborne, D;
- McGinn, C;
- Kohnert, L;
- Migliorini, L;
- Wheaton, A;
- Spencer, B;
- Labonde, C;
- Castillo, G;
- Beerman, G;
- Steward, K;
- Hanley, M;
- Larsen, R;
- Gangopadhyay, R;
- Kloetzel, R;
- Weschler, T;
- Nystrom, V;
- Moffatt, J;
- Redick, M;
- Griest, K;
- Packard, M;
- Muszynski, M;
- Kampmeier, J;
- Bjella, R;
- Flynn, S;
- Elsaesser, B;
- Chambers, KC;
- Flewelling, HA;
- Huber, ME;
- Magnier, EA;
- Waters, CZ;
- Schultz, ASB;
- Bulger, J;
- Lowe, TB;
- Willman, M;
- Smartt, SJ;
- Smith, KW;
- Points, S;
- Strampelli, GM;
- Brimacombe, J;
- Chen, P;
- Muñoz, JA;
- Mutel, RL;
- Shields, J;
- Vallely, PJ;
- Villanueva, S;
- Li, W;
- Wang, X;
- Zhang, J;
- Lin, H;
- Mo, J;
- Zhao, X;
- Sai, H;
- Zhang, X;
- Zhang, K;
- Zhang, T;
- Wang, L;
- Zhang, J;
- Baron, E;
- DerKacy, JM;
- Li, L;
- Chen, Z;
- Xiang, D;
- Rui, L;
- Wang, L;
- Huang, F;
- Li, X;
- Hosseinzadeh, G;
- Howell, DA;
- Arcavi, I;
- Hiramatsu, D;
- Burke, J;
- Valenti, S;
- Tonry, JL;
- Denneau, L;
- Heinze, AN;
- Weiland, H;
- Stalder, B;
- Vinkó, J;
- Sárneczky, K;
- Pál, A;
- Bódi, A;
- Bognár, Zs;
- Csák, B;
- Cseh, B;
- Csörnyei, G;
- Hanyecz, O;
- Ignácz, B;
- Kalup, Cs;
- Könyves-Tóth, R;
- Kriskovics, L;
- Ordasi, A;
- Rajmon, I;
- Sódor, A;
- Szabó, R;
- Szakáts, R;
- Zsidi, G;
- Williams, SC;
- Nordin, J;
- Cartier, R;
- Frohmaier, C;
- Galbany, L;
- Gutiérrez, CP;
- Hook, I;
- Inserra, C;
- Smith, M;
- Sand, DJ;
- Andrews, JE;
- Smith, N;
- Bilinski, C
Published Web Location
https://doi.org/10.3847/2041-8213/aaedb0Abstract
We present an exquisite 30 minute cadence Kepler (K2) light curve of the Type Ia supernova (SN Ia) 2018oh (ASASSN-18bt), starting weeks before explosion, covering the moment of explosion and the subsequent rise, and continuing past peak brightness. These data are supplemented by multi-color Panoramic Survey Telescope (Pan-STARRS1) and Rapid Response System 1 and Cerro Tololo Inter-American Observatory 4 m Dark Energy Camera (CTIO 4-m DECam) observations obtained within hours of explosion. The K2 light curve has an unusual two-component shape, where the flux rises with a steep linear gradient for the first few days, followed by a quadratic rise as seen for typical supernovae (SNe) Ia. This "flux excess" relative to canonical SN Ia behavior is confirmed in our i-band light curve, and furthermore, SN 2018oh is especially blue during the early epochs. The flux excess peaks 2.14 ± 0.04 days after explosion, has a FWHM of 3.12 ± 0.04 days, a blackbody temperature of K, a peak luminosity of , and a total integrated energy of . We compare SN 2018oh to several models that may provide additional heating at early times, including collision with a companion and a shallow concentration of radioactive nickel. While all of these models generally reproduce the early K2 light curve shape, we slightly favor a companion interaction, at a distance of ∼ based on our early color measurements, although the exact distance depends on the uncertain viewing angle. Additional confirmation of a companion interaction in future modeling and observations of SN 2018oh would provide strong support for a single-degenerate progenitor system.
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