We computed a grid of theoretical models to fit the \delta Scuti frequencies of CoRoT 100866999 detected earlier from the CoRoT timeserials .
The pulsating primary star is determined to be a main sequence star with a rotation period of 4.1 ^ { +0.6 } _ { -0.5 } days , rotating slower than the orbital motion .
The fundamental parameters of the primary star are determined to be M = 1.71 ^ { +0.13 } _ { -0.04 } M _ { \odot } , Z = 0.012 ^ { +0.004 } _ { -0.000 } , f _ { ov } = 0.02 ^ { +0.00 } _ { -0.02 } , T _ { eff } = 8024 ^ { +249 } _ { -297 } K , L = 11.898 ^ { +2.156 } _ { -1.847 } L _ { \odot } , \log g = 4.166 ^ { +0.013 } _ { -0.002 } , R = 1.787 ^ { +0.040 } _ { -0.016 } R _ { \odot } , and X _ { c } = 0.488 ^ { +0.011 } _ { -0.020 } , matching well those obtained from the eclipsing light curve analysis .
Based on the model fittings , p _ { 1 } and p _ { 5 } are suggested to be two dipole modes , and p _ { 3 } , p _ { 4 } , p _ { 6 } , and p _ { 7 } to be four quadrupole modes .
In particular , p _ { 4 } and p _ { 7 } are identified as two components of one quintuplet .
Based on the best-fitting model , we find that p _ { 1 } is a g mode and the other nonradial modes have pronounced mixed characters , which give strong constraints on the convective core .
Finally , the relative size of the convective core of CoRoT 100866999 is determined to R _ { conv } / R = 0.0931 ^ { +0.0003 } _ { -0.0013 } .