We present optical and near-infrared photometry and spectroscopy of SN 2009ib , a Type II-P supernova in NGC 1559 .
This object has moderate brightness , similar to those of the intermediate-luminosity SNe 2008in and 2009N .
Its plateau phase is unusually long , lasting for about 130 days after explosion .
The spectra are similar to those of the subluminous SN 2002gd , with moderate expansion velocities .
We estimate the ^ { 56 } { Ni } mass produced as 0.046 \pm 0.015 { M } _ { \sun } .
We determine the distance to SN 2009ib using both the expanding photosphere method ( EPM ) and the standard candle method .
We also apply EPM to SN 1986L , a type II-P SN that exploded in the same galaxy .
Combining the results of different methods , we conclude the distance to NGC 1559 as D = 19.8 \pm 3.0 Mpc .
We examine archival , pre-explosion images of the field taken with the Hubble Space Telescope , and find a faint source at the position of the SN , which has a yellow colour ( ( V - I ) _ { 0 } = 0.85 mag ) .
Assuming it is a single star , we estimate its initial mass as M _ { ZAMS } = 20 { M } _ { \sun } .
We also examine the possibility , that instead of the yellow source the progenitor of SN 2009ib is a red supergiant star too faint to be detected .
In this case we estimate the upper limit for the initial zero-age main sequence mass of the progenitor to be \sim 14 - 17 { M } _ { \sun } .
In addition , we infer the physical properties of the progenitor at the explosion via hydrodynamical modelling of the observables , and estimate the total energy as \sim 0.55 \times 10 ^ { 51 } erg , the pre-explosion radius as \sim 400 { R } _ { \sun } , and the ejected envelope mass as \sim 15 { M } _ { \sun } , which implies that the mass of the progenitor before explosion was \sim 16.5 - 17 { M } _ { \sun } .