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HR 8799

HR 8799 is a planetary system made of a star and at least four directly imaged giant planets. Given its estimated age, about 30 million years, it is very young compared to the Solar System (4.5 billion year old).

The star is larger, more massive and hotter than the Sun: 1.34 solar radii, 1.47 solar masses, and 7430 kelvins (7160 °C). Also, Its spectral type is complex: kA5 hF0 mA5 V λ Boo.

The four planets were discovered by direct imaging: in other words, we managed to get pictures of these objects. You can watch below a video showing these images and see the actual movement of the planets around the star between July 2009 and July 2016.

 

Name Mass(MJ) Radius(RJ) Period(days) Discovery(date)
HR 8799b 7 1.2 164250 2008
HR 8799c 10 1.3 82145 2008
HR 8799d 10 1.2 41054 2008
HR 8799e 9 18000 2010

 

Real images here: https://apod.nasa.gov/apod/ap170201.html

 

 

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Categories: Planet of the month

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