A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS

Thomas G Wilson; Elisa Goffo; Yann Alibert; Davide Gandolfi; Andrea Bonfanti; Carina M Persson; Andrew Collier Cameron; Malcolm Fridlund; Luca Fossati; Judith Korth; Willy Benz; Adrien Deline; Hans-Gustav Florén; Pascal Guterman; Vardan Adibekyan; Matthew J Hooton; Sergio Hoyer; Adrien Leleu; Alexander James Mustill; Sébastien Salmon; Sérgio G Sousa; Olga Suarez; Lyu Abe; Abdelkrim Agabi; Roi Alonso; Guillem Anglada; Joel Asquier; Tamas Bárczy; David Barrado y Navascues; Susana C C Barros; Wolfgang Baumjohann; Mathias Beck; Thomas Beck; Nicolas Billot; Xavier Bonfils; Alexis Brandeker; Christopher Broeg; Edward M Bryant; Matthew R Burleigh; Marco Buttu; Juan Cabrera; Sébastien Charnoz; David R Ciardi; Ryan Cloutier; William D Cochran; Karen A Collins; Knicole D Colón; Nicolas Crouzet; Szilard Csizmadia; Melvyn B Davies; Magali Deleuil; Laetitia Delrez; Olivier Demangeon; Brice-Olivier Demory; Diana Dragomir; Georgina Dransfield; David Ehrenreich; Anders Erikson; Andrea Fortier; Tianjun Gan; Samuel Gill; Michaël Gillon; Crystal L Gnilka; Nolan Grieves; Sascha Grziwa; Manuel Güdel; Tristan Guillot; Jonas Haldemann; Kevin Heng; Keith Horne; Steve B Howell; Kate G Isaak; Jon M Jenkins; Eric L N Jensen; Laszlo Kiss; Gaia Lacedelli; Kristine Lam; Jacques Laskar; David W Latham; Alain  Lecavelier des Etangs; Monika Lendl; Kathryn V Lester; Alan M Levine; John Livingston; Christophe Lovis; Rafael Luque; Demetrio Magrin; Wenceslas Marie-Sainte; Pierre F L Maxted; Andrew W Mayo; Brian McLean; Marko Mecina; Djamel Mékarnia; Valerio Nascimbeni; Louise D Nielsen; Göran Olofsson; Hugh P Osborn; Hannah L M Osborne; Roland Ottensamer; Isabella Pagano; Enric Pallé; Gisbert Peter; Giampaolo Piotto; Don Pollacco; Didier Queloz; Roberto Ragazzoni; Nicola Rando; Heike Rauer; Seth Redfield; Ignasi Ribas; George R Ricker; Martin Rieder; Nuno C Santos; Gaetano Scandariato; François-Xavier Schmider; Richard P Schwarz; Nicholas J Scott; Sara Seager; Damien Ségransan; Luisa Maria Serrano; Attila E Simon; Alexis M S Smith; Manfred Steller; Chris Stockdale; Gyula Szabó; Nicolas Thomas; Eric B Ting; Amaury H M J Triaud; Stéphane Udry; Vincent Van Eylen; Valérie Van Grootel; Roland K Vanderspek; Valentina Viotto; Nicholas Walton; Joshua N Winn

doi:10.1093/mnras/stab3799

A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS

Thomas G Wilson^*, Elisa Goffo, Yann Alibert, Davide Gandolfi, Andrea Bonfanti, Carina M Persson, Andrew Collier Cameron, Malcolm Fridlund, Luca Fossati, Judith Korth, Willy Benz, Adrien Deline, Hans-Gustav Florén, Pascal Guterman, Vardan Adibekyan, Matthew J Hooton, Sergio Hoyer, Adrien Leleu, Alexander James Mustill, Sébastien SalmonSérgio G Sousa, Olga Suarez, Lyu Abe, Abdelkrim Agabi, Roi Alonso, Guillem Anglada, Joel Asquier, Tamas Bárczy, David Barrado y Navascues, Susana C C Barros, Wolfgang Baumjohann, Mathias Beck, Thomas Beck, Nicolas Billot, Xavier Bonfils, Alexis Brandeker, Christopher Broeg, Edward M Bryant, Matthew R Burleigh, Marco Buttu, Juan Cabrera, Sébastien Charnoz, David R Ciardi, Ryan Cloutier, William D Cochran, Karen A Collins, Knicole D Colón, Nicolas Crouzet, Szilard Csizmadia, Melvyn B Davies, Magali Deleuil, Laetitia Delrez, Olivier Demangeon, Brice-Olivier Demory, Diana Dragomir, Georgina Dransfield, David Ehrenreich, Anders Erikson, Andrea Fortier, Tianjun Gan, Samuel Gill, Michaël Gillon, Crystal L Gnilka, Nolan Grieves, Sascha Grziwa, Manuel Güdel, Tristan Guillot, Jonas Haldemann, Kevin Heng, Keith Horne, Steve B Howell, Kate G Isaak, Jon M Jenkins, Eric L N Jensen, Laszlo Kiss, Gaia Lacedelli, Kristine Lam, Jacques Laskar, David W Latham, Alain Lecavelier des Etangs, Monika Lendl, Kathryn V Lester, Alan M Levine, John Livingston, Christophe Lovis, Rafael Luque, Demetrio Magrin, Wenceslas Marie-Sainte, Pierre F L Maxted, Andrew W Mayo, Brian McLean, Marko Mecina, Djamel Mékarnia, Valerio Nascimbeni, Louise D Nielsen, Göran Olofsson, Hugh P Osborn, Hannah L M Osborne, Roland Ottensamer, Isabella Pagano, Enric Pallé, Gisbert Peter, Giampaolo Piotto, Don Pollacco, Didier Queloz, Roberto Ragazzoni, Nicola Rando, Heike Rauer, Seth Redfield, Ignasi Ribas, George R Ricker, Martin Rieder, Nuno C Santos, Gaetano Scandariato, François-Xavier Schmider, Richard P Schwarz, Nicholas J Scott, Sara Seager, Damien Ségransan, Luisa Maria Serrano, Attila E Simon, Alexis M S Smith, Manfred Steller, Chris Stockdale, Gyula Szabó, Nicolas Thomas, Eric B Ting, Amaury H M J Triaud, Stéphane Udry, Vincent Van Eylen, Valérie Van Grootel, Roland K Vanderspek, Valentina Viotto, Nicholas Walton, Joshua N Winn

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

We report the discovery and characterization of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in the Transiting Exoplanet Survey Satellite (TESS) photometry. To characterize the system, we performed and retrieved the CHaracterising ExOPlanets Satellite (CHEOPS), TESS, and ground-based photometry, the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectroscopy, and Gemini speckle imaging. We characterize the host star and determine T_eff,⋆=4734±67K⁠, R_⋆=0.726±0.007R⊙⁠, and M_⋆=0.748±0.032M⊙⁠. We present a novel detrending method based on point spread function shape-change modelling and demonstrate its suitability to correct flux variations in CHEOPS data. We confirm the planetary nature of both bodies and find that TOI-1064 b has an orbital period of P_b = 6.44387 ± 0.00003 d, a radius of R_b = 2.59 ± 0.04 R⊕, and a mass of M_b=13.5^+1.7_−1.8 M⊕, whilst TOI-1064 c has an orbital period of P_c=12.22657^+0.00005_−0.00004 d, a radius of R_c = 2.65 ± 0.04 R⊕, and a 3σ upper mass limit of 8.5 M⊕. From the high-precision photometry we obtain radius uncertainties of ∼1.6 per cent, allowing us to conduct internal structure and atmospheric escape modelling. TOI-1064 b is one of the densest, well-characterized sub-Neptunes, with a tenuous atmosphere that can be explained by the loss of a primordial envelope following migration through the protoplanetary disc. It is likely that TOI-1064 c has an extended atmosphere due to the tentative low density, however further radial velocities are needed to confirm this scenario and the similar radii, different masses nature of this system. The high-precision data and modelling of TOI-1064 b are important for planets in this region of mass–radius space, and it allow us to identify a trend in bulk density–stellar metallicity for massive sub-Neptunes that may hint at the formation of this population of planets.

Original language	English
Pages (from-to)	1043–1071
Number of pages	29
Journal	Monthly Notices of the Royal Astronomical Society
Volume	511
Issue number	1
Early online date	13 Jan 2022
DOIs	https://doi.org/10.1093/mnras/stab3799
Publication status	Published - 1 Mar 2022

Keywords

Planets and satellites: detection
Planets and satellites: composition
Planets and satellites: interiors
Stars: individual: TOI-1064 (TIC 79748331
Gaia EDR3 6683371847364921088)
Techniques: photometric
Techniques: radial velocities

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10.1093/mnras/stab3799Licence: CC BY

Wilson-2022-A-pair-of-sub-Neptunes-MNRAS-511-1-1043-CCBY
Copyright © The Author(s) 2022. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Final published version, 5.47 MBLicence: CC BY

Astronomy at St Andrews 2018-2021: Astronomy at St Andrews 2018-2021
Jardine, M. M. (PI), Bonnell, I. A. (CoI), Cameron, A. C. (CoI), Cyganowski, C. J. (CoI), Dominik, M. (CoI), Helling, C. (CoI), Horne, K. D. (CoI), Scholz, A. (CoI), Tojeiro, R. (CoI), Weijmans, A.-M. (CoI), Wild, V. (CoI), Woitke, P. (CoI), Wood, K. (CoI) & Zhao, H. (CoI)
1/04/18 → 31/03/22
Project: Standard
Support for the PLATO Development: Support for the PLATO Development Phase 2017-2022: Planet candidate ranking and validation
Cameron, A. C. (PI)
Science & Technology Facilities Council
1/08/17 → 31/12/22
Project: Standard

Cite this

Wilson, T. G., Goffo, E., Alibert, Y., Gandolfi, D., Bonfanti, A., Persson, C. M., Cameron, A. C., Fridlund, M., Fossati, L., Korth, J., Benz, W., Deline, A., Florén, H.-G., Guterman, P., Adibekyan, V., Hooton, M. J., Hoyer, S., Leleu, A., Mustill, A. J., ... Winn, J. N. (2022). A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS. Monthly Notices of the Royal Astronomical Society, 511(1), 1043–1071. https://doi.org/10.1093/mnras/stab3799

@article{4ab5ca705e6a4c4096a158d0d57f42ed,

title = "A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS",

abstract = "We report the discovery and characterization of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in the Transiting Exoplanet Survey Satellite (TESS) photometry. To characterize the system, we performed and retrieved the CHaracterising ExOPlanets Satellite (CHEOPS), TESS, and ground-based photometry, the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectroscopy, and Gemini speckle imaging. We characterize the host star and determine Teff,⋆=4734±67K⁠, R⋆=0.726±0.007R⊙⁠, and M⋆=0.748±0.032M⊙⁠. We present a novel detrending method based on point spread function shape-change modelling and demonstrate its suitability to correct flux variations in CHEOPS data. We confirm the planetary nature of both bodies and find that TOI-1064 b has an orbital period of Pb = 6.44387 ± 0.00003 d, a radius of Rb = 2.59 ± 0.04 R⊕, and a mass of Mb=13.5+1.7−1.8 M⊕, whilst TOI-1064 c has an orbital period of Pc=12.22657+0.00005−0.00004 d, a radius of Rc = 2.65 ± 0.04 R⊕, and a 3σ upper mass limit of 8.5 M⊕. From the high-precision photometry we obtain radius uncertainties of ∼1.6 per cent, allowing us to conduct internal structure and atmospheric escape modelling. TOI-1064 b is one of the densest, well-characterized sub-Neptunes, with a tenuous atmosphere that can be explained by the loss of a primordial envelope following migration through the protoplanetary disc. It is likely that TOI-1064 c has an extended atmosphere due to the tentative low density, however further radial velocities are needed to confirm this scenario and the similar radii, different masses nature of this system. The high-precision data and modelling of TOI-1064 b are important for planets in this region of mass–radius space, and it allow us to identify a trend in bulk density–stellar metallicity for massive sub-Neptunes that may hint at the formation of this population of planets.",

keywords = "Planets and satellites: detection, Planets and satellites: composition, Planets and satellites: interiors, Stars: individual: TOI-1064 (TIC 79748331, Gaia EDR3 6683371847364921088), Techniques: photometric, Techniques: radial velocities",

author = "Wilson, {Thomas G} and Elisa Goffo and Yann Alibert and Davide Gandolfi and Andrea Bonfanti and Persson, {Carina M} and Cameron, {Andrew Collier} and Malcolm Fridlund and Luca Fossati and Judith Korth and Willy Benz and Adrien Deline and Hans-Gustav Flor{\'e}n and Pascal Guterman and Vardan Adibekyan and Hooton, {Matthew J} and Sergio Hoyer and Adrien Leleu and Mustill, {Alexander James} and S{\'e}bastien Salmon and Sousa, {S{\'e}rgio G} and Olga Suarez and Lyu Abe and Abdelkrim Agabi and Roi Alonso and Guillem Anglada and Joel Asquier and Tamas B{\'a}rczy and Navascues, {David Barrado y} and Barros, {Susana C C} and Wolfgang Baumjohann and Mathias Beck and Thomas Beck and Nicolas Billot and Xavier Bonfils and Alexis Brandeker and Christopher Broeg and Bryant, {Edward M} and Burleigh, {Matthew R} and Marco Buttu and Juan Cabrera and S{\'e}bastien Charnoz and Ciardi, {David R} and Ryan Cloutier and Cochran, {William D} and Collins, {Karen A} and Col{\'o}n, {Knicole D} and Nicolas Crouzet and Szilard Csizmadia and Davies, {Melvyn B} and Magali Deleuil and Laetitia Delrez and Olivier Demangeon and Brice-Olivier Demory and Diana Dragomir and Georgina Dransfield and David Ehrenreich and Anders Erikson and Andrea Fortier and Tianjun Gan and Samuel Gill and Micha{\"e}l Gillon and Gnilka, {Crystal L} and Nolan Grieves and Sascha Grziwa and Manuel G{\"u}del and Tristan Guillot and Jonas Haldemann and Kevin Heng and Keith Horne and Howell, {Steve B} and Isaak, {Kate G} and Jenkins, {Jon M} and Jensen, {Eric L N} and Laszlo Kiss and Gaia Lacedelli and Kristine Lam and Jacques Laskar and Latham, {David W} and {Lecavelier des Etangs}, Alain and Monika Lendl and Lester, {Kathryn V} and Levine, {Alan M} and John Livingston and Christophe Lovis and Rafael Luque and Demetrio Magrin and Wenceslas Marie-Sainte and Maxted, {Pierre F L} and Mayo, {Andrew W} and Brian McLean and Marko Mecina and Djamel M{\'e}karnia and Valerio Nascimbeni and Nielsen, {Louise D} and G{\"o}ran Olofsson and Osborn, {Hugh P} and Osborne, {Hannah L M} and Roland Ottensamer and Isabella Pagano and Enric Pall{\'e} and Gisbert Peter and Giampaolo Piotto and Don Pollacco and Didier Queloz and Roberto Ragazzoni and Nicola Rando and Heike Rauer and Seth Redfield and Ignasi Ribas and Ricker, {George R} and Martin Rieder and Santos, {Nuno C} and Gaetano Scandariato and Fran{\c c}ois-Xavier Schmider and Schwarz, {Richard P} and Scott, {Nicholas J} and Sara Seager and Damien S{\'e}gransan and Serrano, {Luisa Maria} and Simon, {Attila E} and Smith, {Alexis M S} and Manfred Steller and Chris Stockdale and Gyula Szab{\'o} and Nicolas Thomas and Ting, {Eric B} and Triaud, {Amaury H M J} and St{\'e}phane Udry and {Van Eylen}, Vincent and {Van Grootel}, Val{\'e}rie and Vanderspek, {Roland K} and Valentina Viotto and Nicholas Walton and Winn, {Joshua N}",

note = "Funding: TGW, ACC, and KH acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant ST/R003203/1.",

year = "2022",

month = mar,

day = "1",

doi = "10.1093/mnras/stab3799",

language = "English",

volume = "511",

pages = "1043–1071",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "1",

}

Wilson, TG, Goffo, E, Alibert, Y, Gandolfi, D, Bonfanti, A, Persson, CM, Cameron, AC, Fridlund, M, Fossati, L, Korth, J, Benz, W, Deline, A, Florén, H-G, Guterman, P, Adibekyan, V, Hooton, MJ, Hoyer, S, Leleu, A, Mustill, AJ, Salmon, S, Sousa, SG, Suarez, O, Abe, L, Agabi, A, Alonso, R, Anglada, G, Asquier, J, Bárczy, T, Navascues, DBY, Barros, SCC, Baumjohann, W, Beck, M, Beck, T, Billot, N, Bonfils, X, Brandeker, A, Broeg, C, Bryant, EM, Burleigh, MR, Buttu, M, Cabrera, J, Charnoz, S, Ciardi, DR, Cloutier, R, Cochran, WD, Collins, KA, Colón, KD, Crouzet, N, Csizmadia, S, Davies, MB, Deleuil, M, Delrez, L, Demangeon, O, Demory, B-O, Dragomir, D, Dransfield, G, Ehrenreich, D, Erikson, A, Fortier, A, Gan, T, Gill, S, Gillon, M, Gnilka, CL, Grieves, N, Grziwa, S, Güdel, M, Guillot, T, Haldemann, J, Heng, K, Horne, K, Howell, SB, Isaak, KG, Jenkins, JM, Jensen, ELN, Kiss, L, Lacedelli, G, Lam, K, Laskar, J, Latham, DW, Lecavelier des Etangs, A, Lendl, M, Lester, KV, Levine, AM, Livingston, J, Lovis, C, Luque, R, Magrin, D, Marie-Sainte, W, Maxted, PFL, Mayo, AW, McLean, B, Mecina, M, Mékarnia, D, Nascimbeni, V, Nielsen, LD, Olofsson, G, Osborn, HP, Osborne, HLM, Ottensamer, R, Pagano, I, Pallé, E, Peter, G, Piotto, G, Pollacco, D, Queloz, D, Ragazzoni, R, Rando, N, Rauer, H, Redfield, S, Ribas, I, Ricker, GR, Rieder, M, Santos, NC, Scandariato, G, Schmider, F-X, Schwarz, RP, Scott, NJ, Seager, S, Ségransan, D, Serrano, LM, Simon, AE, Smith, AMS, Steller, M, Stockdale, C, Szabó, G, Thomas, N, Ting, EB, Triaud, AHMJ, Udry, S, Van Eylen, V, Van Grootel, V, Vanderspek, RK, Viotto, V, Walton, N & Winn, JN 2022, 'A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS', Monthly Notices of the Royal Astronomical Society, vol. 511, no. 1, pp. 1043–1071. https://doi.org/10.1093/mnras/stab3799

TY - JOUR

T1 - A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS

AU - Wilson, Thomas G

AU - Goffo, Elisa

AU - Alibert, Yann

AU - Gandolfi, Davide

AU - Bonfanti, Andrea

AU - Persson, Carina M

AU - Cameron, Andrew Collier

AU - Fridlund, Malcolm

AU - Fossati, Luca

AU - Korth, Judith

AU - Benz, Willy

AU - Deline, Adrien

AU - Florén, Hans-Gustav

AU - Guterman, Pascal

AU - Adibekyan, Vardan

AU - Hooton, Matthew J

AU - Hoyer, Sergio

AU - Leleu, Adrien

AU - Mustill, Alexander James

AU - Salmon, Sébastien

AU - Sousa, Sérgio G

AU - Suarez, Olga

AU - Abe, Lyu

AU - Agabi, Abdelkrim

AU - Alonso, Roi

AU - Anglada, Guillem

AU - Asquier, Joel

AU - Bárczy, Tamas

AU - Navascues, David Barrado y

AU - Barros, Susana C C

AU - Baumjohann, Wolfgang

AU - Beck, Mathias

AU - Beck, Thomas

AU - Billot, Nicolas

AU - Bonfils, Xavier

AU - Brandeker, Alexis

AU - Broeg, Christopher

AU - Bryant, Edward M

AU - Burleigh, Matthew R

AU - Buttu, Marco

AU - Cabrera, Juan

AU - Charnoz, Sébastien

AU - Ciardi, David R

AU - Cloutier, Ryan

AU - Cochran, William D

AU - Collins, Karen A

AU - Colón, Knicole D

AU - Crouzet, Nicolas

AU - Csizmadia, Szilard

AU - Davies, Melvyn B

AU - Deleuil, Magali

AU - Delrez, Laetitia

AU - Demangeon, Olivier

AU - Demory, Brice-Olivier

AU - Dragomir, Diana

AU - Dransfield, Georgina

AU - Ehrenreich, David

AU - Erikson, Anders

AU - Fortier, Andrea

AU - Gan, Tianjun

AU - Gill, Samuel

AU - Gillon, Michaël

AU - Gnilka, Crystal L

AU - Grieves, Nolan

AU - Grziwa, Sascha

AU - Güdel, Manuel

AU - Guillot, Tristan

AU - Haldemann, Jonas

AU - Heng, Kevin

AU - Horne, Keith

AU - Howell, Steve B

AU - Isaak, Kate G

AU - Jenkins, Jon M

AU - Jensen, Eric L N

AU - Kiss, Laszlo

AU - Lacedelli, Gaia

AU - Lam, Kristine

AU - Laskar, Jacques

AU - Latham, David W

AU - Lecavelier des Etangs, Alain

AU - Lendl, Monika

AU - Lester, Kathryn V

AU - Levine, Alan M

AU - Livingston, John

AU - Lovis, Christophe

AU - Luque, Rafael

AU - Magrin, Demetrio

AU - Marie-Sainte, Wenceslas

AU - Maxted, Pierre F L

AU - Mayo, Andrew W

AU - McLean, Brian

AU - Mecina, Marko

AU - Mékarnia, Djamel

AU - Nascimbeni, Valerio

AU - Nielsen, Louise D

AU - Olofsson, Göran

AU - Osborn, Hugh P

AU - Osborne, Hannah L M

AU - Ottensamer, Roland

AU - Pagano, Isabella

AU - Pallé, Enric

AU - Peter, Gisbert

AU - Piotto, Giampaolo

AU - Pollacco, Don

AU - Queloz, Didier

AU - Ragazzoni, Roberto

AU - Rando, Nicola

AU - Rauer, Heike

AU - Redfield, Seth

AU - Ribas, Ignasi

AU - Ricker, George R

AU - Rieder, Martin

AU - Santos, Nuno C

AU - Scandariato, Gaetano

AU - Schmider, François-Xavier

AU - Schwarz, Richard P

AU - Scott, Nicholas J

AU - Seager, Sara

AU - Ségransan, Damien

AU - Serrano, Luisa Maria

AU - Simon, Attila E

AU - Smith, Alexis M S

AU - Steller, Manfred

AU - Stockdale, Chris

AU - Szabó, Gyula

AU - Thomas, Nicolas

AU - Ting, Eric B

AU - Triaud, Amaury H M J

AU - Udry, Stéphane

AU - Van Eylen, Vincent

AU - Van Grootel, Valérie

AU - Vanderspek, Roland K

AU - Viotto, Valentina

AU - Walton, Nicholas

AU - Winn, Joshua N

N1 - Funding: TGW, ACC, and KH acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant ST/R003203/1.

PY - 2022/3/1

Y1 - 2022/3/1

N2 - We report the discovery and characterization of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in the Transiting Exoplanet Survey Satellite (TESS) photometry. To characterize the system, we performed and retrieved the CHaracterising ExOPlanets Satellite (CHEOPS), TESS, and ground-based photometry, the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectroscopy, and Gemini speckle imaging. We characterize the host star and determine Teff,⋆=4734±67K⁠, R⋆=0.726±0.007R⊙⁠, and M⋆=0.748±0.032M⊙⁠. We present a novel detrending method based on point spread function shape-change modelling and demonstrate its suitability to correct flux variations in CHEOPS data. We confirm the planetary nature of both bodies and find that TOI-1064 b has an orbital period of Pb = 6.44387 ± 0.00003 d, a radius of Rb = 2.59 ± 0.04 R⊕, and a mass of Mb=13.5+1.7−1.8 M⊕, whilst TOI-1064 c has an orbital period of Pc=12.22657+0.00005−0.00004 d, a radius of Rc = 2.65 ± 0.04 R⊕, and a 3σ upper mass limit of 8.5 M⊕. From the high-precision photometry we obtain radius uncertainties of ∼1.6 per cent, allowing us to conduct internal structure and atmospheric escape modelling. TOI-1064 b is one of the densest, well-characterized sub-Neptunes, with a tenuous atmosphere that can be explained by the loss of a primordial envelope following migration through the protoplanetary disc. It is likely that TOI-1064 c has an extended atmosphere due to the tentative low density, however further radial velocities are needed to confirm this scenario and the similar radii, different masses nature of this system. The high-precision data and modelling of TOI-1064 b are important for planets in this region of mass–radius space, and it allow us to identify a trend in bulk density–stellar metallicity for massive sub-Neptunes that may hint at the formation of this population of planets.

AB - We report the discovery and characterization of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in the Transiting Exoplanet Survey Satellite (TESS) photometry. To characterize the system, we performed and retrieved the CHaracterising ExOPlanets Satellite (CHEOPS), TESS, and ground-based photometry, the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectroscopy, and Gemini speckle imaging. We characterize the host star and determine Teff,⋆=4734±67K⁠, R⋆=0.726±0.007R⊙⁠, and M⋆=0.748±0.032M⊙⁠. We present a novel detrending method based on point spread function shape-change modelling and demonstrate its suitability to correct flux variations in CHEOPS data. We confirm the planetary nature of both bodies and find that TOI-1064 b has an orbital period of Pb = 6.44387 ± 0.00003 d, a radius of Rb = 2.59 ± 0.04 R⊕, and a mass of Mb=13.5+1.7−1.8 M⊕, whilst TOI-1064 c has an orbital period of Pc=12.22657+0.00005−0.00004 d, a radius of Rc = 2.65 ± 0.04 R⊕, and a 3σ upper mass limit of 8.5 M⊕. From the high-precision photometry we obtain radius uncertainties of ∼1.6 per cent, allowing us to conduct internal structure and atmospheric escape modelling. TOI-1064 b is one of the densest, well-characterized sub-Neptunes, with a tenuous atmosphere that can be explained by the loss of a primordial envelope following migration through the protoplanetary disc. It is likely that TOI-1064 c has an extended atmosphere due to the tentative low density, however further radial velocities are needed to confirm this scenario and the similar radii, different masses nature of this system. The high-precision data and modelling of TOI-1064 b are important for planets in this region of mass–radius space, and it allow us to identify a trend in bulk density–stellar metallicity for massive sub-Neptunes that may hint at the formation of this population of planets.

KW - Planets and satellites: detection

KW - Planets and satellites: composition

KW - Planets and satellites: interiors

KW - Stars: individual: TOI-1064 (TIC 79748331

KW - Gaia EDR3 6683371847364921088)

KW - Techniques: photometric

KW - Techniques: radial velocities

U2 - 10.1093/mnras/stab3799

DO - 10.1093/mnras/stab3799

M3 - Article

SN - 0035-8711

VL - 511

SP - 1043

EP - 1071

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 1

ER -

A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS

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Astronomy at St Andrews 2018-2021: Astronomy at St Andrews 2018-2021

Support for the PLATO Development: Support for the PLATO Development Phase 2017-2022: Planet candidate ranking and validation

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