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Exoplanetary Scratchpad

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Libertas (Xi Aquilae) is a 4.7 magnitude, 1.16 MS, 10.4 RS, 4.6 BYO GK clump giant star (in helium burning phase) 184 ly away with a 2.8 MJ planet (Fortitudo) at 0.68 AU. Its spectrum is on the border between an orange and yellow star, and it used to be on the border between a white and blue main sequence star and has only 2/3 the metals as the Sun. The planet is one of three planets around GK clump giants found by a Japanese observatory, and the star is the brightest of the three host stars. When found, the planet has the shortest period (136d) of any found around evolved stars and it is possible that any planets closer in would have been consumed when the star expanded into a Red Giant. The star is very near Altair in Aquila. One of the first 20 exoplanet systems allowed to be given common names by the IAU. Star and planet are latin for Liberty and Fortitude, as represented by an Eagle.

My Thoughts[]

No wonder all these giant star planets seem to have long Earth-like periods. Good luck ever seeing the star, it wasn't even labelled on Wikipedia's map, but it's close enough to Altair that I should be able to gaze at it's general direction in my front yard. Maybe it'd be a good binocular target. This star is "barely" more massive than the Sun, yet it seems to have evolved off the main sequence very quickly and originated from a much more luminous class of star. How is this possible? An error in data? Is its low metalicity a part of it?


It's in the Eagle constellation. Discovered by Japan.

- Houoh - a phoenix like bird with a tree that it perches on. - Gobidin - Eagle and Feather in another language - Cradle/Magpie - Chinese lore with a bird in it - Hoshinokataribe - talking about stars, references the nearby Altair.

Totally lost this one, but it's still appropriate.

Libertas System Web Pages[]

Libertas System In the News[]

Planets Discovered Around 3 Intermediate Mass Clump Giants (2008)[]

See also 18 Delphinis System, HD 81688 System

Testing Engulfment Theory Around GK Clump Giants (2011)[]

One of the Top 20 Exoplanetary Systems First Up For Naming (May 2015)[]

Fun Links[]

See Also[]