The ^ { 16 } OH/ ^ { 18 } OH and OD/OH isotope ratios are measured in the Oort-Cloud comet C/2002 T7 ( LINEAR ) through ground-based observations of the OH A ^ { 2 } \Sigma ^ { + } - X ^ { 2 } \Pi _ { i } ultraviolet bands at 3063 Å ( 0,0 ) and 3121 Å ( 1,1 ) secured with the Very Large Telescope ( VLT ) feeding the Ultraviolet-Visual Echelle Spectrograph ( UVES ) .
From the ^ { 16 } OH/ ^ { 18 } OH ratio , we find ^ { 16 } O/ ^ { 18 } O = 425 \pm 55 , equal within the uncertainties to the terrestrial value and to the ratio measured in other comets , although marginally smaller .
We also estimate OD/OH from which we derive D/H = 2.5 \pm 0.7 10 ^ { -4 } in water .
This value is compatible with the water D/H ratios evaluated in other comets and marginally higher than the terrestrial value .