The Draco Dwarf spheroidal (dSph) galaxy is one of the nearest and the most dark-matter-dominated satellites of the Milky Way. We obtained multiepoch near-infrared (NIR, JHKs) observations of the central region of Draco dSph covering a sky area of ~21x21' using the WIRCam instrument at the 3.6m Canada-France-Hawaii Telescope. Homogeneous JHKs time-series photometry for 212 RR Lyrae (173 fundamental-mode, 24 first-overtone, and 15 mixed-mode variables) and five Anomalous Cepheids in Draco dSph are presented and used to derive their period-luminosity relations at NIR wavelengths for the first- time. The small scatter of ~0.05mag in these empirical relations for RR Lyrae stars is consistent with those in globular clusters and suggests a very small metallicity spread, up to ~0.2dex, among these centrally located variables. Based on empirically calibrated NIR period-luminosity-metallicity relations for RR Lyrae in globular clusters, we determined a distance modulus to Draco dSph of {mu}RRL=19.557{+/-}0.026mag. The calibrated Ks-band period-luminosity relations for Anomalous Cepheids in the Draco dSph and the Large Magellanic Cloud exhibit statistically consistent slopes but systematically different zero points, hinting at possible metallicity dependence of ~-0.3mag/dex. Finally, the apparent magnitudes of the tip of the red-giant branch in I and J bands also agree well with their absolute calibrations with the adopted RR Lyrae distance to Draco. Our recommended ~1.5% precise RR Lyrae distance, DDraco=81.55{+/-}0.98(statistical){+/-}1.17(systematic)kpc, is the most accurate and precise distance to Draco dSph galaxy.

Cone search capability for table J/AJ/167/247/table2 (NIR pulsation properties of variable stars in Draco dSph)