A photometric UBV survey is presented for 610 stars in a region surrounding the Cepheid AQ Puppis and centered southwest of the variable , based upon photoelectric measures for 14 stars and calibrated iris photometry of photographic plates of the field for 596 stars .
An analysis of reddening and distance for program stars indicates that the major dust complex in this direction is \sim 1.8 kpc distant , producing differential extinction described by a ratio of total-to-selective extinction of R = A _ { V } / E _ { B - V } = 3.10 \pm 0.20 .
Zero-age main-sequence fitting for the main group of B-type stars along the line of sight yields a distance of 3.21 \pm 0.19 kpc ( V _ { 0 } - M _ { V } = 12.53 \pm 0.13 s.e . ) .
The 29 ^ { d } .97 Cepheid AQ Pup , of field reddening E _ { B - V } = 0.47 \pm 0.07 ( E _ { B - V } { ( B 0 ) } = 0.51 \pm 0.07 ) , appears to be associated with B-type stars lying within 5 \arcmin of it as well as with a sparse group of stars , designated Turner 14 , centered south of it at J2000.0 = 07:58:37 , –29:25:00 , with a mean reddening of E _ { B - V } = 0.81 \pm 0.01 .
AQ Pup has an inferred luminosity as a cluster member of \langle M _ { V } \rangle = -5.40 \pm 0.25 and an evolutionary age of 3 \times 10 ^ { 7 } yr. Its observed rate of period increase of +300.1 \pm 1.2 s yr ^ { -1 } is an order of magnitude larger than what is observed for Cepheids of comparable period in the third crossing of the instability strip , and may be indicative of a high rate of mass loss or a putative fifth crossing .
Another sparse cluster , designated Turner 13 , surrounds the newly-recognized 2 ^ { d } .59 Cepheid V620 Pup , of space reddening E _ { B - V } = 0.64 \pm 0.02 ( E _ { B - V } { ( B 0 ) } = 0.68 \pm 0.02 ) , distance 2.88 \pm 0.11 kpc ( V _ { 0 } - M _ { V } = 12.30 \pm 0.08 s.e .
) , evolutionary age 10 ^ { 8 } yr , and an inferred luminosity as a likely cluster member of \langle M _ { V } \rangle = -2.74 \pm 0.11 .
V620 Pup is tentatively identified as a first crosser , pending additional observations .