Calculation of the "lightness number" for solar sails

[Val---]

Hello,
In the wikipedia article about solar sails the lightness number is mentioned and the calculation is the characteristic acceleration ac divided by the Sun´s local gravity (distance: 1AU): λ = ac / 5.93

why do they use 5,93 m/s^2 for the sun´s gravity and not 274 m/s^2?

 

[Bandersnatch]

why do they use 5,93 m/s^2 for the sun´s gravity and not 274 m/s^2?

They don't use 5.93 m/s^2, but 5.93 mm/s^2, or 0.0053 m/s^2. They do this, because that's the gravitational acceleration at the distance of 1 AU.
274 m/s^2 is the surface gravity, which falls with the square of the distance.