Given that,
Eccentricity = 0.0086
Suppose, The length of half of the major axis is [tex]1\times10^{9}\ km[/tex]
We need to calculate the distance from the center to the foci
Using formula of eccentricity
[tex]e=\dfrac{c}{a}[/tex]
[tex]c=e\times a[/tex]
Where, e = eccentricity
a = major axis
c = the distance from the center to the foci
Put the value in to the formula
[tex]c=0.0086\times1\times10^{9}[/tex]
[tex]c=8600000[/tex]
We need to calculate the perihelion distance of Neptune from the sun
Using formula of distance
[tex]d=a-c[/tex]
Put the value into the formula
[tex]d=1\times10^{9}-0.0086\times10^{9}[/tex]
[tex]d=991400000\ km[/tex]
Hence, The perihelion distance of Neptune from the sun is 991400000 km.