Saved in:
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2026
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2605.12324 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866918497823490048 |
|---|---|
| author | Eschen, Yoshi Nike Emilia Wilson, Thomas G. Cameron, Andrew Collier Mustill, Alexander James Egger, Jo Ann Ulmer-Moll, Solène Gandolfi, Davide Smith, Alexis M. S. Demangeon, Olivier D. S. Sousa, Sérgio G. Bonfanti, Andrea Correia, Alexandre C. M. Adibekyan, Vardan Lacedelli, Gaia Brandeker, Alexis Pezzotti, Camilla Akinsanmi, Babatunde Alibert, Yann Alonso, Roi Bárczy, Tamas Barrado, David Barros, Susana C. C. Baumjohann, Wolfgang Benz, Willy Billot, Nicolas Borsato, Luca Broeg, Christopher Castro-González, Amadeo Csizmadia, Szilard Cubillos, Patricio E. Davies, Melvyn B. Deleuil, Magali Deline, Adrien Demory, Brice-Olivier Derekas, Aliz Di Persio, Giuseppe Edwards, Billy Ehrenreich, David Erikson, Anders Fortier, Andrea Fossati, Luca Fridlund, Malcolm Gazeas, Kosmas Gillon, Michaël Güdel, Manuel Günther, Maximilian N. Heitzmann, Alexis Helling, Ch. Isaak, Kate G. Jenkins, Jon M. Keller, Tatiana Kiss, Laszlo L. Kitzmann, Daniel Korth, Judith Lam, Kristine W. F. Laskar, Jacques Etangs, Alain Lecavelier des Leleu, Adrien Lendl, Monika Magrin, Demetrio Maxted, Pierre F. L. Merín, Bruno Mordasini, Christoph Nascimbeni, Valerio Olofsson, Göran Osborn, Hugh P. Ottensamer, Roland Pagano, Isabella Pallé, Enric Peter, Gisbert Petitpas, Glen Piazza, Daniele Piotto, Giampaolo Pollacco, Don Queloz, Didier Ragazzoni, Roberto Rando, Nicola Rauer, Heike Ribas, Ignasi Santos, Nuno C. Scandariato, Gaetano Ségransan, Damien Shporer, Avi Silva, André M. Simon, Attila E. Southworth, Richard Stalport, Manu Sulis, Sophia Szabó, Gyula M. Udry, Stéphane Ulmer, Bernd Van Grootel, Valérie Venturini, Julia Villaver, Eva Walton, Nicholas A. Wolf, Sebastian Ziegler, Carl Zingales, Tiziano |
| author_facet | Eschen, Yoshi Nike Emilia Wilson, Thomas G. Cameron, Andrew Collier Mustill, Alexander James Egger, Jo Ann Ulmer-Moll, Solène Gandolfi, Davide Smith, Alexis M. S. Demangeon, Olivier D. S. Sousa, Sérgio G. Bonfanti, Andrea Correia, Alexandre C. M. Adibekyan, Vardan Lacedelli, Gaia Brandeker, Alexis Pezzotti, Camilla Akinsanmi, Babatunde Alibert, Yann Alonso, Roi Bárczy, Tamas Barrado, David Barros, Susana C. C. Baumjohann, Wolfgang Benz, Willy Billot, Nicolas Borsato, Luca Broeg, Christopher Castro-González, Amadeo Csizmadia, Szilard Cubillos, Patricio E. Davies, Melvyn B. Deleuil, Magali Deline, Adrien Demory, Brice-Olivier Derekas, Aliz Di Persio, Giuseppe Edwards, Billy Ehrenreich, David Erikson, Anders Fortier, Andrea Fossati, Luca Fridlund, Malcolm Gazeas, Kosmas Gillon, Michaël Güdel, Manuel Günther, Maximilian N. Heitzmann, Alexis Helling, Ch. Isaak, Kate G. Jenkins, Jon M. Keller, Tatiana Kiss, Laszlo L. Kitzmann, Daniel Korth, Judith Lam, Kristine W. F. Laskar, Jacques Etangs, Alain Lecavelier des Leleu, Adrien Lendl, Monika Magrin, Demetrio Maxted, Pierre F. L. Merín, Bruno Mordasini, Christoph Nascimbeni, Valerio Olofsson, Göran Osborn, Hugh P. Ottensamer, Roland Pagano, Isabella Pallé, Enric Peter, Gisbert Petitpas, Glen Piazza, Daniele Piotto, Giampaolo Pollacco, Don Queloz, Didier Ragazzoni, Roberto Rando, Nicola Rauer, Heike Ribas, Ignasi Santos, Nuno C. Scandariato, Gaetano Ségransan, Damien Shporer, Avi Silva, André M. Simon, Attila E. Southworth, Richard Stalport, Manu Sulis, Sophia Szabó, Gyula M. Udry, Stéphane Ulmer, Bernd Van Grootel, Valérie Venturini, Julia Villaver, Eva Walton, Nicholas A. Wolf, Sebastian Ziegler, Carl Zingales, Tiziano |
| contents | We report the discovery and characterisation of the multi-planetary system around TOI-4311, a K dwarf kinematically between the Galactic thick disk and Hercules stream. TOI-4311 hosts an ultra-short-period super-Earth (P$\sim$0.99 d, $1.376\substack{+0.077\\-0.080}$ R$_\oplus$) and a longer period sub-Neptune (P$\sim$15 d, $2.47\substack{+0.12\\-0.11}$ R$_\oplus$) that was first detected in the TESS photometry. Using follow-up observations with CHEOPS and HARPS, we refine the planetary radius of both planets, derive the mass of planet b ($4.5\substack{+1.5\\-1.4}$ M$_\oplus$) and confirm the planetary nature of planet c. Intriguingly, a third periodic signal is clearly detected in our HARPS RVs that we cannot link to stellar activity. This signal could be attributed to a third planet (P$\sim$38 d, Msin(i)=$26.4\substack{+6.3\\-6.8}$ M$_\oplus$) in the system, however with the current photometric dataset we do not find a transit. Our dynamical analysis highlights that this potential outer planet would remain stable. Using the precise radius and mass for TOI-4311 b we model its interior structure and find that it is very dense given the host star's galactic kinematics and chemistry. Hence this system could challenge current formation theories and provide insights into planet formation across the galaxy. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_12324 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | An Ultra-Short Period Super-Earth and a Sub-Neptune Orbiting the K dwarf TOI-4311 Eschen, Yoshi Nike Emilia Wilson, Thomas G. Cameron, Andrew Collier Mustill, Alexander James Egger, Jo Ann Ulmer-Moll, Solène Gandolfi, Davide Smith, Alexis M. S. Demangeon, Olivier D. S. Sousa, Sérgio G. Bonfanti, Andrea Correia, Alexandre C. M. Adibekyan, Vardan Lacedelli, Gaia Brandeker, Alexis Pezzotti, Camilla Akinsanmi, Babatunde Alibert, Yann Alonso, Roi Bárczy, Tamas Barrado, David Barros, Susana C. C. Baumjohann, Wolfgang Benz, Willy Billot, Nicolas Borsato, Luca Broeg, Christopher Castro-González, Amadeo Csizmadia, Szilard Cubillos, Patricio E. Davies, Melvyn B. Deleuil, Magali Deline, Adrien Demory, Brice-Olivier Derekas, Aliz Di Persio, Giuseppe Edwards, Billy Ehrenreich, David Erikson, Anders Fortier, Andrea Fossati, Luca Fridlund, Malcolm Gazeas, Kosmas Gillon, Michaël Güdel, Manuel Günther, Maximilian N. Heitzmann, Alexis Helling, Ch. Isaak, Kate G. Jenkins, Jon M. Keller, Tatiana Kiss, Laszlo L. Kitzmann, Daniel Korth, Judith Lam, Kristine W. F. Laskar, Jacques Etangs, Alain Lecavelier des Leleu, Adrien Lendl, Monika Magrin, Demetrio Maxted, Pierre F. L. Merín, Bruno Mordasini, Christoph Nascimbeni, Valerio Olofsson, Göran Osborn, Hugh P. Ottensamer, Roland Pagano, Isabella Pallé, Enric Peter, Gisbert Petitpas, Glen Piazza, Daniele Piotto, Giampaolo Pollacco, Don Queloz, Didier Ragazzoni, Roberto Rando, Nicola Rauer, Heike Ribas, Ignasi Santos, Nuno C. Scandariato, Gaetano Ségransan, Damien Shporer, Avi Silva, André M. Simon, Attila E. Southworth, Richard Stalport, Manu Sulis, Sophia Szabó, Gyula M. Udry, Stéphane Ulmer, Bernd Van Grootel, Valérie Venturini, Julia Villaver, Eva Walton, Nicholas A. Wolf, Sebastian Ziegler, Carl Zingales, Tiziano Earth and Planetary Astrophysics We report the discovery and characterisation of the multi-planetary system around TOI-4311, a K dwarf kinematically between the Galactic thick disk and Hercules stream. TOI-4311 hosts an ultra-short-period super-Earth (P$\sim$0.99 d, $1.376\substack{+0.077\\-0.080}$ R$_\oplus$) and a longer period sub-Neptune (P$\sim$15 d, $2.47\substack{+0.12\\-0.11}$ R$_\oplus$) that was first detected in the TESS photometry. Using follow-up observations with CHEOPS and HARPS, we refine the planetary radius of both planets, derive the mass of planet b ($4.5\substack{+1.5\\-1.4}$ M$_\oplus$) and confirm the planetary nature of planet c. Intriguingly, a third periodic signal is clearly detected in our HARPS RVs that we cannot link to stellar activity. This signal could be attributed to a third planet (P$\sim$38 d, Msin(i)=$26.4\substack{+6.3\\-6.8}$ M$_\oplus$) in the system, however with the current photometric dataset we do not find a transit. Our dynamical analysis highlights that this potential outer planet would remain stable. Using the precise radius and mass for TOI-4311 b we model its interior structure and find that it is very dense given the host star's galactic kinematics and chemistry. Hence this system could challenge current formation theories and provide insights into planet formation across the galaxy. |
| title | An Ultra-Short Period Super-Earth and a Sub-Neptune Orbiting the K dwarf TOI-4311 |
| topic | Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2605.12324 |