The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272
We report the discovery of an eccentric hot Neptune and a non-transiting outer planet around TOI-1272. We identified the eccentricity of the inner planet, with an orbital period of 3.3 days and Rp,b = 4.1 ± 0.2 R⊕, based on a mismatch between the observed transit duration and the expected duration f...
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| Format: | Article |
| Language: | English |
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American Astronomical Society
2023
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| Online Access: | https://hdl.handle.net/1721.1/148411 |
| _version_ | 1826216207029633024 |
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| 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 an eccentric hot Neptune and a non-transiting outer planet around TOI-1272. We identified the eccentricity of the inner planet, with an orbital period of 3.3 days and Rp,b = 4.1 ± 0.2 R⊕, based on a mismatch between the observed transit duration and the expected duration for a circular orbit. Using ground-based radial velocity (RV) measurements from the HIRES instrument at the Keck Observatory, we measured the mass of TOI-1272b to be Mp,b = 25 ± 2 M⊕. We also confirmed a high eccentricity of eb = 0.34 ± 0.06, placing TOI-1272b among the most eccentric well-characterized sub-Jovians. We used these RV measurements to also identify a non-transiting outer companion on an 8.7 day orbit with a similar mass of Mp,c sin i = 27 ± 3 M⊕ and ec ≲ 0.35. Dynamically stable planet–planet interactions have likely allowed TOI-1272b to avoid tidal eccentricity decay despite the short circularization timescale expected for a close-in eccentric Neptune. TOI-1272b also maintains an envelope mass fraction of fenv ≈ 11% despite its high equilibrium temperature, implying that it may currently be undergoing photoevaporation. This planet joins a small population of short-period Neptune-like planets within the "Hot Neptune Desert" with a poorly understood formation pathway. |
| first_indexed | 2024-09-23T16:43:40Z |
| format | Article |
| id | mit-1721.1/148411 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T16:43:40Z |
| publishDate | 2023 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1484112023-03-08T03:02:03Z The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272 Seager, Sara Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences We report the discovery of an eccentric hot Neptune and a non-transiting outer planet around TOI-1272. We identified the eccentricity of the inner planet, with an orbital period of 3.3 days and Rp,b = 4.1 ± 0.2 R⊕, based on a mismatch between the observed transit duration and the expected duration for a circular orbit. Using ground-based radial velocity (RV) measurements from the HIRES instrument at the Keck Observatory, we measured the mass of TOI-1272b to be Mp,b = 25 ± 2 M⊕. We also confirmed a high eccentricity of eb = 0.34 ± 0.06, placing TOI-1272b among the most eccentric well-characterized sub-Jovians. We used these RV measurements to also identify a non-transiting outer companion on an 8.7 day orbit with a similar mass of Mp,c sin i = 27 ± 3 M⊕ and ec ≲ 0.35. Dynamically stable planet–planet interactions have likely allowed TOI-1272b to avoid tidal eccentricity decay despite the short circularization timescale expected for a close-in eccentric Neptune. TOI-1272b also maintains an envelope mass fraction of fenv ≈ 11% despite its high equilibrium temperature, implying that it may currently be undergoing photoevaporation. This planet joins a small population of short-period Neptune-like planets within the "Hot Neptune Desert" with a poorly understood formation pathway. 2023-03-07T19:51:01Z 2023-03-07T19:51:01Z 2022 2023-03-07T19:47:23Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/148411 Seager, Sara. 2022. "The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272." Astronomical Journal, 164 (3). en 10.3847/1538-3881/AC7CE1 Astronomical Journal Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf American Astronomical Society The American Astronomical Society |
| spellingShingle | Seager, Sara The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272 |
| title | The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272 |
| title_full | The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272 |
| title_fullStr | The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272 |
| title_full_unstemmed | The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272 |
| title_short | The TESS–Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-mass Outer Companion around TOI-1272 |
| title_sort | tess keck survey xiii an eccentric hot neptune with a similar mass outer companion around toi 1272 |
| url | https://hdl.handle.net/1721.1/148411 |
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