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We present photometry and spectra of the type IIP SN1999em in NGC 1637 from several days after the outburst till day 642. An amount of $approx 0.02 M_{odot}$ of ejected $^{56}$Ni is inferred using the recovered bolometric light curve . The H$alpha$ and He I 10830 AA lines at the nebular epoch show that the distribution of the bulk of $^{56}$Ni can be represented approximately by a sphere of $^{56}$Ni with a velocity of 1500 km s$^{-1}$, which is shifted towards the far hemisphere by about 400 km s$^{-1}$. The fine structure of the H$alpha$ at the photospheric epoch reminiscent of the Bochum event in SN 1987A is analysed . The late time spectra show a dramatic transformation of the [O I] 6300 AA line profile between days 465 and 510, which we interpret as an effect of dust condensation during this period. Late time photometry supports the dust formation scenario after day 465. The [O I] line profile suggests that the dust occupies a sphere with velocity $approx 800$ km s$^{-1}$ and optical depth $gg10$. The plateau brightness and duration combined with the expansion velocity suggest a presupernova radius of $120-150 R_{odot}$, ejecta mass of $10-11 M_{odot}$ and explosion energy of $(0.5-1)times10^{51}$ erg. The ejecta mass combined with the neutron star and a conservative assumption about mass loss implies the main sequence progenitor of $M_{rm ms}approx 12-14 M_{odot}$. From the [O I] 6300,6364 AA doublet luminosity we infer the oxygen mass to be a factor four lower than in SN 1987A which is consistent with the estimated SN 1999em progenitor mass . We note a second-plateau behaviour of the light curve after the main plateau at the beginning of the radioactive tail. This feature seems to be common to SNe IIP with low $^{56}$Ni mass.
We present extensive optical ($UBVRI$, $griz$, and open CCD) and near-infrared ($ZYJH$) photometry for the very nearby Type IIP SN ~2013ej extending from +1 to +461 days after shock breakout, estimated to be MJD $56496.9pm0.3$. Substantial time serie
The enigmatic type IIP SN 2016X demonstrates the unprecedented asphericity in the nebular H-alpha line profile, the absence of nebular [O I] emission, and the unusual occultation effect due to the internal dust. The hydrodynamic modelling of the bolo
We present the results the photometric observations of the Type IIP supernova SN 2012aw obtained for the time interval from 7 till 371 days after the explosion. Using the previously published values of the photospheric velocities weve computed the hy
Type IIP supernovae (SNe IIP), which represent the most common class of core-collapse (CC) SNe, show a rapid increase in continuum polarization just after entering the tail phase. This feature can be explained by a highly asymmetric helium core, whic
The explosion energy and the ejecta mass of a type IIP supernova (SN IIP) derived from hydrodynamic simulations are principal parameters of the explosion theory. However, the number of SNe IIP studied by hydrodynamic modeling is small. Moreover, some