| Summary: | In this paper, we investigate a scalar field cosmological model of accelerating Universe with the simplest parametrization of the equation of state parameter of the scalar field. We use <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></semantics></math></inline-formula> data, pantheon compilation of SN Ia data and BAO data to constrain the model parameters using the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>χ</mi><mn>2</mn></msup></semantics></math></inline-formula> minimization technique. We obtain the present values of Hubble constant <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>H</mi><mn>0</mn></msub></semantics></math></inline-formula> as <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>66</mn><mo>.</mo><msubsup><mn>2</mn><mrow><mo>−</mo><mn>1.34</mn></mrow><mrow><mo>+</mo><mn>1.42</mn></mrow></msubsup></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>70</mn><mo>.</mo><msubsup><mn>7</mn><mrow><mo>−</mo><mn>0.31</mn></mrow><mrow><mo>+</mo><mn>0.32</mn></mrow></msubsup></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>67</mn><mo>.</mo><msubsup><mn>74</mn><mrow><mo>−</mo><mn>1.04</mn></mrow><mrow><mo>+</mo><mn>1.24</mn></mrow></msubsup></mrow></semantics></math></inline-formula> for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></semantics></math></inline-formula> + Pantheon and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></semantics></math></inline-formula> + BAO respectively. In addition, we estimate the present age of the Universe in a derived model <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>t</mi><mn>0</mn></msub><mo>=</mo><mn>14</mn><mo>.</mo><msubsup><mn>38</mn><mrow><mo>−</mo><mn>0.64</mn></mrow><mrow><mo>+</mo><mn>0.63</mn></mrow></msubsup></mrow></semantics></math></inline-formula> for joint <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></semantics></math></inline-formula> and pantheon compilation of SN Ia data which has only <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.88</mn><mspace width="3.33333pt"></mspace><mi>σ</mi></mrow></semantics></math></inline-formula> tension with its empirical value obtained in Plank collaboration. Moreover, the present values of the deceleration parameter <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>q</mi><mn>0</mn></msub></semantics></math></inline-formula> come out to be <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>−</mo><mn>0</mn><mo>.</mo><msubsup><mn>55</mn><mrow><mo>−</mo><mn>0.038</mn></mrow><mrow><mo>+</mo><mn>0.031</mn></mrow></msubsup></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>−</mo><mn>0</mn><mo>.</mo><msubsup><mn>61</mn><mrow><mo>−</mo><mn>0.021</mn></mrow><mrow><mo>+</mo><mn>0.030</mn></mrow></msubsup></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>−</mo><mn>0</mn><mo>.</mo><msubsup><mn>627</mn><mrow><mo>−</mo><mn>0.025</mn></mrow><mrow><mo>+</mo><mn>0.022</mn></mrow></msubsup></mrow></semantics></math></inline-formula> by bounding the Universe in the derived model with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></semantics></math></inline-formula> + Pantheon compilation of SN Ia and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></semantics></math></inline-formula> + BAO data sets, respectively. We also have performed the state-finder diagnostics to discover the nature of dark energy.
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