HD star with transiting planet the closest Hot-Jupiter exoplanet to Earth, so it is well studied

Star: – 63 lyrs – K1-2V (R star = 0.81 R Sun ) Planet: – 1.16 M Jupiter – AU – 2.2 day period Lightcurve: – What is the percent drop in light? – 0.02 = [R planet /R star ] 2 – R planet = 0.11 R Sun = 1.1 R Jupiter

Globular Cluster Activity measure distance to center of galaxy

Globular Cluster

These white dwarf stars are very faint. About the brightness of a 100 watt light-bulb at the moon’s distance. An 8 day long exposure with the Hubble Space Telescope 99% of All Stars Become White Dwarfs M4: ~6,000 light-years away ~1 light-year Messier 4: The nearest globular cluster to us. The brightness of the white dwarfs tells us how long they have been cooling billion years