Extrasolar Planets
The stellar obliquity ψs, i.e. the axial tilt of a star with respect to the orbital plane of one of its planets, has been determined for only a few systems. But for 49 stars as of today, the sky-projected spin-orbit misalignment λ has been observed, which serves as a lower limit to ψs. Most of these measurements rely on the so-called Rossiter-McLaughlin effect. So far, it has not been possible to constrain the obliquity of an extrasolar planet. But the rotational flattening of the planet and the entourage of moons and/or rings, which are traceable with high-precision photometry, e.g. by the space-based Kepler spacecraft, could provide access to ψp in the near future.
Astrophysicists have applied tidal theories to predict the obliquity of extrasolar planets. It has been shown that the obliquities of exoplanets in the habitable zone around low-mass stars tend to be eroded in less than 1 Gyr, which means that they would not have seasons as Earth has.
Read more about this topic: Axial Tilt
Famous quotes containing the word planets:
“I would sell my life to avoid
the pain that begins in the crib
with its bars or perhaps
with your first breath
when the planets drill
your future into you....”
—Anne Sexton (1928–1974)