The discovery of an
extrasolar planet orbiting HD 179949 with a
period of only 3.1 days was published in 2001. It was detected with the
radial velocity method from observations of the star with the UCLES
spectrograph, in the
Anglo-Australian Telescope, as part of the
Anglo-Australian Planet Search. With a
minimum mass of 92% of the
mass of Jupiter, it is a
hot Jupiter, orbiting the star at a distance of only 0.04
AU. Its orbit is nearly circular, with a best fit
orbital eccentricity of 0.022 ± 0.015. Planets close to their stars have high chances of
transit, but
photometric observations of HD 179949 ruled out this possibility.
Infrared observations of HD 179949 with the
Spitzer Space Telescope detected 0.14% variations in the system's brightness in phase with the orbital period of the planet, indicating large luminosity variation between the illuminated side and the dark side of the planet, implying that less than 21% of the incident stellar energy is transferred to the dark side. In 2014, infrared observations of the system with the CRIRES instrument, at the
Very Large Telescope, directly detected the thermal spectrum of the planet, revealing
absorption features of
carbon monoxide and
water vapor in its atmosphere. The radial velocity of the planet has variations of 142.8 ± 3.4 km/s due to orbital motion, which allowed the calculation of a real mass of 0.98 ± 0.04 Jupiter masses and an orbital
inclination of 67.7 ± 4.3 degrees. ==References==