The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166
We report the discovery of HIP-97166b (TOI-1255b), a transiting sub-Neptune on a 10.3 day orbit around a K0 dwarf 68 pc from Earth. This planet was identified in a systematic search of TESS Objects of Interest for planets with eccentric orbits, based on a mismatch between the observed transit durati...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
American Astronomical Society
2023
|
| Online Access: | https://hdl.handle.net/1721.1/148526 |
| _version_ | 1826195756899368960 |
|---|---|
| author | Seager, Sara |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Seager, Sara |
| author_sort | Seager, Sara |
| collection | MIT |
| description | We report the discovery of HIP-97166b (TOI-1255b), a transiting sub-Neptune on a 10.3 day orbit around a K0 dwarf 68 pc from Earth. This planet was identified in a systematic search of TESS Objects of Interest for planets with eccentric orbits, based on a mismatch between the observed transit duration and the expected duration for a circular orbit. We confirmed the planetary nature of HIP-97166b with ground-based radial-velocity measurements and measured a mass of Mb = 20 ± 2 M⊕ along with a radius of Rb = 2.7 ± 0.1 R⊕ from photometry. We detected an additional nontransiting planetary companion with Mc sini = 10 ± 2 M⊕ on a 16.8 day orbit. While the short transit duration of the inner planet initially suggested a high eccentricity, a joint RV-photometry analysis revealed a high impact parameter b = 0.84 ± 0.03 and a moderate eccentricity. Modeling the dynamics with the condition that the system remain stable over >105 orbits yielded eccentricity constraints eb = 0.16 ± 0.03 and ec < 0.25. The eccentricity we find for planet b is above average for the small population of sub-Neptunes with well-measured eccentricities. We explored the plausible formation pathways of this system, proposing an early instability and merger event to explain the high density of the inner planet at 5.3 ± 0.9 g cc−1 as well as its moderate eccentricity and proximity to a 5:3 mean-motion resonance. |
| first_indexed | 2024-09-23T10:14:57Z |
| format | Article |
| id | mit-1721.1/148526 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T10:14:57Z |
| publishDate | 2023 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1485262023-03-14T03:42:46Z The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166 Seager, Sara Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences We report the discovery of HIP-97166b (TOI-1255b), a transiting sub-Neptune on a 10.3 day orbit around a K0 dwarf 68 pc from Earth. This planet was identified in a systematic search of TESS Objects of Interest for planets with eccentric orbits, based on a mismatch between the observed transit duration and the expected duration for a circular orbit. We confirmed the planetary nature of HIP-97166b with ground-based radial-velocity measurements and measured a mass of Mb = 20 ± 2 M⊕ along with a radius of Rb = 2.7 ± 0.1 R⊕ from photometry. We detected an additional nontransiting planetary companion with Mc sini = 10 ± 2 M⊕ on a 16.8 day orbit. While the short transit duration of the inner planet initially suggested a high eccentricity, a joint RV-photometry analysis revealed a high impact parameter b = 0.84 ± 0.03 and a moderate eccentricity. Modeling the dynamics with the condition that the system remain stable over >105 orbits yielded eccentricity constraints eb = 0.16 ± 0.03 and ec < 0.25. The eccentricity we find for planet b is above average for the small population of sub-Neptunes with well-measured eccentricities. We explored the plausible formation pathways of this system, proposing an early instability and merger event to explain the high density of the inner planet at 5.3 ± 0.9 g cc−1 as well as its moderate eccentricity and proximity to a 5:3 mean-motion resonance. 2023-03-13T18:12:19Z 2023-03-13T18:12:19Z 2021 2023-03-13T18:04:08Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/148526 Seager, Sara. 2021. "The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166." Astronomical Journal, 162 (6). en 10.3847/1538-3881/AC295E Astronomical Journal Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf American Astronomical Society arXiv |
| spellingShingle | Seager, Sara The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166 |
| title | The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166 |
| title_full | The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166 |
| title_fullStr | The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166 |
| title_full_unstemmed | The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166 |
| title_short | The TESS–Keck Survey. VI. Two Eccentric Sub-Neptunes Orbiting HIP-97166 |
| title_sort | tess keck survey vi two eccentric sub neptunes orbiting hip 97166 |
| url | https://hdl.handle.net/1721.1/148526 |
| work_keys_str_mv | AT seagersara thetesskecksurveyvitwoeccentricsubneptunesorbitinghip97166 AT seagersara tesskecksurveyvitwoeccentricsubneptunesorbitinghip97166 |