We present X-ray , broad band optical and low frequency radio observations of the bright type IIP supernova SN 2004et .
The Chandra X-ray Observatory  observed the supernova at three epochs , and the optical coverage spans a period of \sim 470 days since explosion .
The X-ray emission softens with time , and we characterise the X-ray luminosity evolution as L _ { \mathrm { x } } \propto t ^ { -0.4 } .
We use the observed X-ray luminosity to estimate a mass-loss rate for the progenitor star of \sim { 2 } \times 10 ^ { -6 } ~ { } M _ { \odot } ~ { } \mathrm { yr } ^ { -1 } .
The optical light curve shows a pronounced plateau lasting for about 110 days .
Temporal evolution of photospheric radius and color temperature during the plateau phase is determined by making black body fits .
We estimate the ejected mass of ^ { 56 } Ni to be 0.06 \pm 0.03 M _ { \odot } .
Using the expressions of Litvinova & Nadà « zhin ( 1985 ) we estimate an explosion energy of ( 0.98 \pm 0.25 ) \times 10 ^ { 51 } erg .
We also present a single epoch radio observation of SN 2004et .
We compare this with the predictions of the model proposed by Chevalier et al .
( 2006 ) .
These multi-wavelength studies suggest a main sequence progenitor mass of \sim 20 M _ { \odot } for SN 2004et .