An ablating 2.6 M⊕ planet in an eccentric binary from the Dispersed Matter Planet Project
Abstract
Earth-mass exoplanets are difficult to detect. The Dispersed Matter Planet Project (DMPP) identifies stars that are likely to host the most detectable low-mass exoplanets. The star DMPP-3 (HD 42936) shows signs of circumstellar absorption, indicative of mass loss from ablating planets. Here, we report the radial velocity discovery of a highly eccentric 507 d binary companion and a hot super-Earth-mass planet in a 6.67 d orbit around the primary star. DMPP-3A is a solar-type star while DMPP-3B is just massive enough to fuse hydrogen. The binary, with semi-major axis 1.22 ± 0.02 au, is considerably tighter than others known to host planets orbiting only one of the component stars. The configuration of the DMPP-3 planetary system is rare and indicates dynamical interactions, though the evolutionary history is not entirely clear. DMPP-3A b is possibly the residual core of a giant planet precursor, consistent with the inferred circumstellar gas shroud.
- Publication:
-
Nature Astronomy
- Pub Date:
- January 2020
- DOI:
- 10.1038/s41550-019-0972-z
- arXiv:
- arXiv:1912.10793
- Bibcode:
- 2020NatAs...4..419B
- Keywords:
-
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for publication by Nature Astronomy on 12th November 2019 (Main article, Methods and Supplementary Information