The orange dot circled and labelled 'B' is a planet circling the Sun-like star GJ 758, seen by the light it emits. It's a big planet, between 10-40 times the mass of Jupiter, and is at a temperature of around 320 degrees Centigrade. Its orbit is very likely eccentric, like Pluto's, and it's about the same distance from its star as Neptune is from the sun, so it isn't being warmed by insolation. Either it's relatively young and at the low end of the estimated mass range, and is emitting heat as it contracts, or it's fairly large and much older - a smallish brown dwarf. The other dot, labelled 'C' may be another planet, or a background star, or an imaging glitch.
It was spotted during the first run of a new adaptive optics instrument that eliminates atmospheric interference of Earth-based telescopic images and is part of a survey programme searching for extra-solar planets. Wonder what else it will find?
Universe Today has more info; a preview of the paper describing the observations is here.
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