New X-ray ( XMM-Newton ) and JHK _ { s } ( OMM ) observations for members of the star cluster Alessi 95 , which Turner et al . ( 48 ) discovered hosts the classical Cepheid SU Cas , were used in tandem with UCAC3 ( proper motion ) and 2MASS observations to determine precise cluster parameters : E ( J - H ) = 0.08 \pm 0.02 and d = 405 \pm 15 pc .
The ensuing consensus among cluster , pulsation , IUE , and trigonometric distances ( d = 414 \pm 5 ( \sigma _ { \bar { x } } ) \pm 10 ( \sigma ) pc ) places SU Cas in a select group of nearby fundamental Cepheid calibrators ( \delta Cep , \zeta Gem ) .
High-resolution X-ray observations may be employed to expand that sample as the data proved pertinent for identifying numerous stars associated with SU Cas .
Acquiring X-ray observations of additional fields may foster efforts to refine Cepheid calibrations used to constrain H _ { 0 } .