(star system thought to host the first detected exoplanet)
The HD 114762 multiple star system includes an object
once considered an extra-solar planet-candidate which would have been
the first exoplanet discovered, but which has since been
classified as a star. The system is now considered a triple star
consisting of an F-type star and two smaller stars, each of the
latter two either a red dwarf or brown dwarf.
The early-proposed exoplanet-candidate was discovered in 1989, based
upon the radial velocity method, and its existence was confirmed in 1991.
Its early mass determination of 11 Jupiter masses was
small enough to be considered a planet, but subsequent observation
and analysis determine it to be more massive, likely 147 Jupiter
masses. The second small stellar companion was discovered through
direct imaging during follow-up observations and also initially
an exoplanet-candidate, but spectrography and the likely mass
that it implies suggests it is a star. It has a large orbit, making
direct imaging (and spectrography) of it effective, while the earlier
discovered companion is in a small orbit, giving it radial velocity
cycle short enough to for practical detection.
Each of the companions is determined to be either a red dwarf or
a brown dwarf; the defined difference is whether the object ever
has or will experience hydrogen burning, but this is sometimes unclear:
their mass ranges overlap and some spectral types can be either
of the two. Also, their masses are not precisely known: only a
calculated probability density function based upon observable data.
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