Special 

Pluto and Ceres: fresh views of dwarf planets

In 2015, scientists got their best glimpse yet of dwarf planets, when two NASA spacecraft visited distant worlds. In March, the Dawn mission arrived at Ceres, which lies in the asteroid belt between Mars and Jupiter; water ice may lurk under the protoplanet's crust. On 14 July, the New Horizons spacecraft reached the far edge of the Solar System, buzzing by Pluto before continuing on to the Kuiper belt.

Nature Podcast
Reporter Alex Witze recounts the New Horizons fly-by from mission headquarters (starts at 19:45).
Nature (16 July 2015)

Nature Podcast
Reporter Alex Witze talks about the Dawn and New Horizons missions to dwarf planets (starts at 8:34).
Nature (25 February 2015)

Video: Why Pluto?
Humans have spent almost a decade getting a spacecraft, New Horizons, all the way to Pluto – but why did we go to so much effort? Nature Video takes a look at the history of this famous 'non-planet' and asks why it is that we care so much about Pluto.
Nature Video (25 June 2015)

Hubble telescope to search for spacecraft target beyond Pluto
NASA seeks to identify icy world in the outer Solar System for New Horizons flyby.
Nature (16 June 2014)

Pluto might be the largest dwarf planet after all
Eris is almost exactly the same size as Pluto — and possibly even a bit smaller.
Scientific American (14 October 2011)

Dawn mission revealing secrets of the early Solar System (link to )
Scientists report first results from rendezvous with Vesta
Nature (04 October 2011)