Diligent sleuthing by astronomers has broken open a cold case in the data archive of NASA’s Hubble Space Telescope. In a study published Monday in Nature Astronomy, researchers report uncovering a chemical clue that shows the white dwarf star HS 0209+0832 may host a second-generation planet.
A white dwarf is the remnant core of a low-mass star that has burned through all its nuclear fuel and lost its outer envelope of gas and dust to space. A second-generation planet is a world that forms around the remnant from its cast-off material.
When Hubble first observed the star in 1999, the data contained about 100 chemical features that could not be identified. Williams went back to those records armed with an updated chemical database and found that niobium matched many of the mystery features.
Once the star ejected this chemically enriched material, the team theorizes that some of it coalesced into a gas giant planet.
The research team confirmed the Hubble observations with data from NASA's retired FUSE mission, which also showed strong signatures of niobium in the HS 0209+0832 system.
NASA’s TESS also observed the white dwarf for four months, allowing it to detect periodic brightness variations that show that a planet orbits at a distance of about 3.7 million miles, much closer than Mercury orbits the Sun.
Despite this mass loss, Williams said that the planet is likely not a temporary blip on the cosmic radar.
NASA’s Hubble Space Telescope spectrum shows the abundances of certain elements it found in the HS 0209+0832 system.