Asteroseismic study of HR 8799

The planetary system host HR 8799: On its λ Bootis nature

Study of the chemically-peculiar exoplanet host star HR 8799. Seems that the λ Boötis nature extends deeper into the star than the most accepted theory of these stars suggests.

And another one, looks like there is the possibility that the star is much older than previously thought (perhaps over a billion years), implying higher masses for the planets.

This paper agrees, saying HR 8799 is probably 1 Gyr in age and that it's three companions are actually brown dwarfs.

However, according to this paper, the system stability requires the planets to be ~100 Myr old.

Quote :

If we as-
sume that the equatorial plane of the star coincides with the orbital plane of the planets and the dust-producing planetesimals (i.e. I_∗ = I_pl = I_disk ), these observational constraints indicate that indeed the inclination of the star is likely inside the 18° < I_∗ < 36° range where the astroseismology models cannot be applied, or that it is close to 36° where they permit solutions consistent with the ∼ 100 Myr age derived from other considerations.

So it looks like the star is likely to be orientated at an inclination where the asteroseismological models don't work. Pity because that may reduce its value as an indicator of how the λ Boötis phenomenon works.