High-resolution ALMA and HST images of q1 Eri: an asymmetric debris disc with an eccentric Jupiter
Abstract
We present Atacama Large Millimetre/sub-Millimetre Array (ALMA) 1.3 and 0.86 mm observations of the nearby (17.34 pc) F9V star q1 Eri (HD 10647, HR 506). This system, with age ~1.4 Gyr, hosts a ~2 au radial velocity planet and a debris disc with the highest fractional luminosity of the closest 300 FGK type stars. The ALMA images, with resolution ~0${_{.}^{\prime\prime}}$5, reveal a broad (34-134 au) belt of millimetre emission inclined by 76.7 ± 1.0 degrees with maximum brightness at 81.6 ± 0.5 au. The images reveal an asymmetry, with higher flux near the south-west ansa, which is also closer to the star. Scattered light observed with the Hubble Space Telescope is also asymmetric, being more radially extended to the north-east. We fit the millimetre emission with parametric models and place constraints on the disc morphology, radius, width, dust mass, and scale height. We find that the south-west ansa asymmetry is best fitted by an extended clump on the inner edge of the disc, consistent with perturbations from a planet with mass $8\, M_{\oplus } {-} 11\, M_{\rm Jup}$ at ~60 au that may have migrated outwards, similar to Neptune in our Solar system. If the measured vertical aspect ratio of h = 0.04 ± 0.01 is due to dynamical interactions in the disc, then this requires perturbers with sizes >1200 km. We find tentative evidence for a 0.86 mm excess within 10 au, $70{\pm }22\, \mu$Jy, that may be due to an inner planetesimal belt. We find no evidence for CO gas, but set an upper bound on the CO gas mass of 4 × 10-6 M⊕ ($3\sigma$), consistent with cometary abundances in the Solar system.
- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 2021
- DOI:
- arXiv:
- arXiv:2106.05975
- Bibcode:
- 2021MNRAS.506.1978L
- Keywords:
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- techniques: interferometric;
- planets and satellites: dynamical evolution and stability;
- (stars:) circumstellar matter;
- stars: individual: HD 10647;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for publication in MNRAS. Paper: 21 pages, appendix: 4 pages. 16 figures