Infrared photometry of Nova Delphini 2013 (=V339 Del) in the first sixty days after its outburst

Abstract

The results of JHKLM photometry for Nova Delphini 2013 obtained in the first sixty days after its outburst are analyzed. Analysis of the energy distribution in a wide spectral range (0.36–5 µm) has shown that the source mimics the emission of normal supergiants of spectral types B5 and A0 for two dates near its optical brightness maximum, August 15.94 UT and August 16.86 UT, respectively. The distance to the nova has been estimated to be D ≈ 3 kpc. For these dates, the following parameters have been estimated: the source’s bolometric fluxes ∼9 × 10−7 and ∼7.2 × 10−7 erg s−1 cm−2, luminosities L ≈ 2.5 × 105 L ⊙ and ≈2 × 105 L ⊙, and radii R ≈ 6.3 × 1012 and ≈1.2 × 1013 cm. The nova’s expansion velocity near its optical brightness maximum was ∼700 km s−1. An infrared (IR) excess associated with the formation of a dust shell is shown to have appeared in the energy distribution one month after the optical brightness maximum. The parameters of the dust component have been estimated for two dates of observations, JD2456557.28 (September 21, 2013) and JD2456577.18 (October 11, 2013). For these dates, the dust shell parameters have been estimated: the color temperatures ≈1500 and ≈1200 K, radii ≈6.5 × 1013 and 1.7 × 1014 cm, luminosities ∼4 × 103 L ⊙ and ∼1.1 × 104 L ⊙, and the dust mass ∼1.6 × 1024 and ∼1025 g. The total mass of the material ejected in twenty days (gas + dust) could reach ∼1.1 × 10−6 M ⊙. The rate of dust supply to the nova shell was ∼8 × 10−8 M ⊙ yr−1. The expansion velocity of the dust shell was about 600 km s−1.