Saved in:
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2507.08464 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866911521359003648 |
|---|---|
| author | Taş, Kaya Han Stefansson, Gudmundur Fariz, Syarief N. M. Garg, Esha Espinoza-Retamal, Juan I. Koo, Elise Bruijne, David Luhn, Jacob Ford, Eric B. Mahadevan, Suvrath Logsdon, Sarah E. Cañas, Caleb I. Han, Te Everett, Mark E. Alvarado-Montes, Jaime A. Blake, Cullen Cochran, William D. Dong, Jiayin Fernandes, Rachel B. Giovinazzi, Mark R. Halverson, Samuel Kanodia, Shubham Krolikowski, Daniel McElwain, Michael Ninan, Joe Paredes, Leonardo A. Robertson, Paul Schwab, Christian |
| author_facet | Taş, Kaya Han Stefansson, Gudmundur Fariz, Syarief N. M. Garg, Esha Espinoza-Retamal, Juan I. Koo, Elise Bruijne, David Luhn, Jacob Ford, Eric B. Mahadevan, Suvrath Logsdon, Sarah E. Cañas, Caleb I. Han, Te Everett, Mark E. Alvarado-Montes, Jaime A. Blake, Cullen Cochran, William D. Dong, Jiayin Fernandes, Rachel B. Giovinazzi, Mark R. Halverson, Samuel Kanodia, Shubham Krolikowski, Daniel McElwain, Michael Ninan, Joe Paredes, Leonardo A. Robertson, Paul Schwab, Christian |
| contents | We present the discovery and confirmation of the ultra-short period (USP) planet TOI-2431 b orbiting a nearby ($d\sim36$ pc) late K star ($T_{\mathrm{eff}}$ = $4109 \pm 28 \, {\rm K}$) using observations from the Transiting Exoplanet Survey Satellite (TESS), precise radial velocities with the NEID and the Habitable-zone Planet Finder (HPF) spectrographs, as well as ground-based high contrast imaging from NESSI. TOI-2431 b has a period of 5 hours and 22 minutes, making it one of the shortest-period exoplanets known to date. TOI-2431 b has a radius of $1.536 \pm 0.033\, \rm{R_\oplus}$, and a mass of $6.2 \pm 1.2\, \rm{M_\oplus}$, suggesting it has a density compatible with an Earth-like composition and, due to its high irradiation, is likely a 'lava-world' with a $T_{\mathrm{eq}}$ = $2063 \pm 30 \, {\rm K}$. We estimate that the current orbital period is only 30% larger than the Roche-limit orbital period, and that it has an expected orbital decay timescale of only $\sim$31 Myr. Finally, due to the brightness of the host star ($V = 10.9$, $K = 7.6$), TOI-2431 b has a high Emission Spectroscopy Metric of 27, making it one of the best USP systems for atmospheric phase-curve analysis. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_08464 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | An Earth-Sized Planet in a 5.4h Orbit Around a Nearby K dwarf Taş, Kaya Han Stefansson, Gudmundur Fariz, Syarief N. M. Garg, Esha Espinoza-Retamal, Juan I. Koo, Elise Bruijne, David Luhn, Jacob Ford, Eric B. Mahadevan, Suvrath Logsdon, Sarah E. Cañas, Caleb I. Han, Te Everett, Mark E. Alvarado-Montes, Jaime A. Blake, Cullen Cochran, William D. Dong, Jiayin Fernandes, Rachel B. Giovinazzi, Mark R. Halverson, Samuel Kanodia, Shubham Krolikowski, Daniel McElwain, Michael Ninan, Joe Paredes, Leonardo A. Robertson, Paul Schwab, Christian Earth and Planetary Astrophysics We present the discovery and confirmation of the ultra-short period (USP) planet TOI-2431 b orbiting a nearby ($d\sim36$ pc) late K star ($T_{\mathrm{eff}}$ = $4109 \pm 28 \, {\rm K}$) using observations from the Transiting Exoplanet Survey Satellite (TESS), precise radial velocities with the NEID and the Habitable-zone Planet Finder (HPF) spectrographs, as well as ground-based high contrast imaging from NESSI. TOI-2431 b has a period of 5 hours and 22 minutes, making it one of the shortest-period exoplanets known to date. TOI-2431 b has a radius of $1.536 \pm 0.033\, \rm{R_\oplus}$, and a mass of $6.2 \pm 1.2\, \rm{M_\oplus}$, suggesting it has a density compatible with an Earth-like composition and, due to its high irradiation, is likely a 'lava-world' with a $T_{\mathrm{eq}}$ = $2063 \pm 30 \, {\rm K}$. We estimate that the current orbital period is only 30% larger than the Roche-limit orbital period, and that it has an expected orbital decay timescale of only $\sim$31 Myr. Finally, due to the brightness of the host star ($V = 10.9$, $K = 7.6$), TOI-2431 b has a high Emission Spectroscopy Metric of 27, making it one of the best USP systems for atmospheric phase-curve analysis. |
| title | An Earth-Sized Planet in a 5.4h Orbit Around a Nearby K dwarf |
| topic | Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2507.08464 |