A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host.

The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300-10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref.

Worldwide variations in artificial skyglow.

Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties.

Hematology and plasma biochemistry reference range values for free-ranging desert tortoises in Arizona.

Baseline values and ranges for 10 hematologic and 32 plasma chemistry parameters were analyzed for 36 free-ranging Sonoran desert tortoises (Gopherus agassizzi) collected in Yavapai and La Paz Counties (Arizona, USA) from 1990 to 1995. Tortoises were radio tagged from 1990 to 1994, and attempts were made to recapture them three times a year. Tortoises were weighed, measured, and chemically immobilized to collect blood for hematology and blood chemistry assessments.