160">We analyzed Spitzer IRAC, MIPS, and IRS observations of Comet 29P.

165">We applied a NEATM to extracted nucleus spectral flux density measurements.

170">We measured an effective radius 1-s2.0-S0019103515002900&_mathId=si55.gif&_user=111111111&_pii=S0019103515002900&_rdoc=1&_issn=00191035&md5=ec9afd91cd945157ca978629e232cc25">1" width="86" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0019103515002900-si55.gif">$R=30.2_{-2.9}^{+3.7}$ km and an infrared beaming parameter 1-s2.0-S0019103515002900&_mathId=si56.gif&_user=111111111&_pii=S0019103515002900&_rdoc=1&_issn=00191035&md5=d7c1e73e844bbfd295e877ccd420ef76">1-s2.0-S0019103515002900-si56.gif">$畏=0.99{}_{-\mathrm{0.<font\; color="red">1</font>9}}^{+0.26}$.

175">Using IRS SED we modeled the come dust composition of 29P.