HR 7291 Sagittarii

(The Planet Project)



The circle shows the location of the class F star HR 7291, found in the constellation Sagittarius. The planet is a "hot Jupiter" with a mass of at least 0.84 Jupiter masses. It orbits very close to its star in only 3.09 days at a mean distance of just 0.045 Astrnomical Units (6.8 million kilometers, 4.2 million miles), or 12 percent the size of Mercury's orbit. As expected for such a close planet, the orbit is nearly circular, though a small eccentricity causes the distance between the planet and star to change by about three percent either way.


HR 7291, also called HD 179949, is a sixth magnitude (6.25) class F8 dwarf star in Sagittarius. Too faint to have a proper or Greek letter name, it is known best by its numbers in the Bright Star(HR) and the Henry Draper (HD) Catalogues. From a distance of 88 light years, it shines with a luminosity 1.8 times that of the Sun from a surface with a temperature of 6250 Kelvin, almost 500 degrees hotter than the Sun. From these values, we infer a radius 1.16 times solar, a mass 1.25 solar, and that the star is very young. Like the majority of planet-holding stars, HR 6907 is metal-rich, with an iron content (relative to hydrogen) that is 65 percent greater than solar.

HR 6907 Sagittarii, at the center of the picture, has two orbiting planets.
Written by Jim Kaler. Return to The Planet Project or go to STARS.