|
Hubble and TESS Data Hint at “Second-Generation” Planet
The news comprises an international research team’s report of a candidate “second-generation” (phoenix) planet orbiting the young white dwarf HS 0209+0832. The evidence comprises spectroscopic data from the Hubble Space Telescope and photometric data from NASA’s Transiting Exoplanet Survey Satellite showing atmospheric contamination and periodic light fluctuation consistent with a close-in exoplanet.
Candidate Second-Generation Planet:
| Dimension | Key Details |
|---|---|
| Stellar host | HS 0209+0832 comprises a hot, young white dwarf with a cooling age of about 5 million years. |
| Distance | HS 0209+0832 comprises a location of approximately 270 light-years away. |
| Hubble finding | Hubble Space Telescope spectroscopic data comprises extreme photospheric contamination in the white dwarf’s atmosphere. |
| Trans-iron enrichments | The atmospheric contamination comprises massive enrichments of trans-iron elements, including zinc, copper, and niobium, at concentrations over 1,000 times higher than in the Sun. |
| s-process implication | The s-process elements comprise heavy elements created exclusively via the slow neutron-capture process inside giant stars before shedding outer envelopes, and this signature comprises an origin from the star’s own ejected layers rather than terrestrial or rocky asteroids. |
| TESS finding | TESS photometric data comprises a periodic 4.4-day light fluctuation that matches a close-in, gas-giant-sized exoplanet undergoing photo-evaporation and mass transfer onto the white dwarf. |
| First-generation planets (formation mechanism) | First-generation planets comprise planets formed within the initial protoplanetary disc surrounding a main-sequence star. |
| First-generation planets (environment) | It comprise formation in protoplanetary discs of young, hydrogen-fusing stars. |
| Second-generation planets (formation mechanism) | Second-generation planets comprise planets formed out of debris or ejected gas expelled during a star’s Asymptotic Giant Branch (AGB) or Red Giant death phase. |
| Second-generation planets (environment) | It comprise formation in debris discs or post-common envelope envelopes surrounding compact stellar remnants like white dwarfs or pulsars. |
| Significance | The significance comprises: planet formation not being restricted to early stellar life; insights into the distant future of the Solar System around 5 billion years from now; and second-generation planet candidates previously inferred around pulsars like PSR B1257+12 now comprising extension to white dwarfs. |