Starship Asterisk*

[img3="This artist's concept shows a hypothetical "rejuvenated" planet -- a gas giant that has reclaimed its youthful infrared glow. NASA's Spitzer Space Telescope found tentative evidence for one such planet around a dead star, or white dwarf, called PG 0010+280 (depicted as white dot in illustration). (Credit: NASA/JPL-Caltech/R. Hurt (IPAC))"]http://www.spitzer.caltech.edu/uploaded ... 09_Med.jpg[/img3][hr][/hr]

For a planet, this would be like a day at the spa. After years of growing old, a massive planet could, in theory, brighten up with a radiant, youthful glow. Rejuvenated planets, as they are nicknamed, are only hypothetical. But new research from NASA's Spitzer Space Telescope has identified one such candidate, seemingly looking billions of years younger than its actual age. ...

How might a planet reclaim the essence of its youth? Years ago, astronomers predicted that some massive, Jupiter-like planets might accumulate mass from their dying stars. As stars like our sun age, they puff up into red giants and then gradually lose about half or more of their mass, shrinking into skeletons of stars, called white dwarfs. The dying stars blow winds of material outward that could fall onto giant planets that might be orbiting in the outer reaches of the star system.

Thus, a giant planet might swell in mass, and heat up due to friction felt by the falling material. This older planet, having cooled off over billions of years, would once again radiate a warm, infrared glow. ...

• Astrophysical Journal Letters 806(1) L5 (10 Jun 2015) DOI: 10.1088/2041-8205/806/1/L5
  arXiv.org > astro-ph > arXiv:1505.02614 > 11 May 2015