_version_ 1866908765073178624
author Barragán, Oscar
Mallorquín, Manuel
Fernández-Fernández, Jorge
Hawthorn, Faith
Freckelton, Alix V.
Lafarga, Marina
Cretignier, Michael
Eschen, Yoshi N. E.
Gill, Samuel
Béjar, Víctor J. S.
Lodieu, Nicolas
Yu, Haochuan
Wilson, Thomas G.
Anderson, David
Apergis, Ioannis
Battley, Matthew
Bryant, Edward M.
Cortés-Zuleta, Pía
Gillen, Edward
Jenkins, James S.
Klein, Baptiste
McCormac, James
Meech, Annabella
Meier-Valdés, Erik
Moyano, Maximiliano
Mortier, Annelies
Murgas, Felipe
Nielsen, Louise D.
Saha, Suman
Vines, José I.
West, Richard
Wheatley, Peter J.
Aigrain, Suzanne
author_facet Barragán, Oscar
Mallorquín, Manuel
Fernández-Fernández, Jorge
Hawthorn, Faith
Freckelton, Alix V.
Lafarga, Marina
Cretignier, Michael
Eschen, Yoshi N. E.
Gill, Samuel
Béjar, Víctor J. S.
Lodieu, Nicolas
Yu, Haochuan
Wilson, Thomas G.
Anderson, David
Apergis, Ioannis
Battley, Matthew
Bryant, Edward M.
Cortés-Zuleta, Pía
Gillen, Edward
Jenkins, James S.
Klein, Baptiste
McCormac, James
Meech, Annabella
Meier-Valdés, Erik
Moyano, Maximiliano
Mortier, Annelies
Murgas, Felipe
Nielsen, Louise D.
Saha, Suman
Vines, José I.
West, Richard
Wheatley, Peter J.
Aigrain, Suzanne
contents The young TOI-451 planetary system, aged 125 Myr, provides a unique opportunity to test theories of planetary internal structures and atmospheric mass loss through examination of its three transiting planets. We present an exhaustive photometric and spectroscopic follow-up to determine the orbital and physical properties of the system. We perform multidimensional Gaussian Process regression with the code pyaneti on spectroscopic time-series and NGTS/LCO light curves to disentangle the stellar and planetary signal in ESPRESSO radial velocities. We show how contemporaneous photometry serves as an activity indicator to inform RV modelling within a multidimensional Gaussian Processes framework. We argue that this can be exploited when spectroscopic observations are adversely affected by low signal-to-noise and/or poor sampling. We estimate the Doppler semi-amplitudes of Kb = 2.6(+1.1,-1.2) m/s, Kc = 1.2(+1.0,-0.8) m/s and Kd = 2.7 +/- 1.2 m/s. This translates into 2-sigma mass estimates for TOI-451 b and d of Mb = 4.7(+2.1,-2.2) Earth masses and Md = 10.2(+4.6,-4.5) Earth masses, as well as a mass upper limit for TOI-451 c of Mc < 11.5 Earth masses. The derived planetary properties suggest that planets c and d contain significant hydrogen-rich envelopes. The inferred parameters of TOI-451 b are consistent with either a rocky world that still retains a small hydrogen envelope or a water world. These insights make the TOI-451 system an ideal laboratory for future follow-up studies aimed at measuring atmospheric compositions, detecting atmospheric mass-loss signatures, and further exploring planetary formation and evolution processes.
format Preprint
id arxiv_https___arxiv_org_abs_2601_09438
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Mass estimates of the young TOI-451 transiting planets: Multidimensional Gaussian Process on stellar spectroscopic and photometric signals
Barragán, Oscar
Mallorquín, Manuel
Fernández-Fernández, Jorge
Hawthorn, Faith
Freckelton, Alix V.
Lafarga, Marina
Cretignier, Michael
Eschen, Yoshi N. E.
Gill, Samuel
Béjar, Víctor J. S.
Lodieu, Nicolas
Yu, Haochuan
Wilson, Thomas G.
Anderson, David
Apergis, Ioannis
Battley, Matthew
Bryant, Edward M.
Cortés-Zuleta, Pía
Gillen, Edward
Jenkins, James S.
Klein, Baptiste
McCormac, James
Meech, Annabella
Meier-Valdés, Erik
Moyano, Maximiliano
Mortier, Annelies
Murgas, Felipe
Nielsen, Louise D.
Saha, Suman
Vines, José I.
West, Richard
Wheatley, Peter J.
Aigrain, Suzanne
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
The young TOI-451 planetary system, aged 125 Myr, provides a unique opportunity to test theories of planetary internal structures and atmospheric mass loss through examination of its three transiting planets. We present an exhaustive photometric and spectroscopic follow-up to determine the orbital and physical properties of the system. We perform multidimensional Gaussian Process regression with the code pyaneti on spectroscopic time-series and NGTS/LCO light curves to disentangle the stellar and planetary signal in ESPRESSO radial velocities. We show how contemporaneous photometry serves as an activity indicator to inform RV modelling within a multidimensional Gaussian Processes framework. We argue that this can be exploited when spectroscopic observations are adversely affected by low signal-to-noise and/or poor sampling. We estimate the Doppler semi-amplitudes of Kb = 2.6(+1.1,-1.2) m/s, Kc = 1.2(+1.0,-0.8) m/s and Kd = 2.7 +/- 1.2 m/s. This translates into 2-sigma mass estimates for TOI-451 b and d of Mb = 4.7(+2.1,-2.2) Earth masses and Md = 10.2(+4.6,-4.5) Earth masses, as well as a mass upper limit for TOI-451 c of Mc < 11.5 Earth masses. The derived planetary properties suggest that planets c and d contain significant hydrogen-rich envelopes. The inferred parameters of TOI-451 b are consistent with either a rocky world that still retains a small hydrogen envelope or a water world. These insights make the TOI-451 system an ideal laboratory for future follow-up studies aimed at measuring atmospheric compositions, detecting atmospheric mass-loss signatures, and further exploring planetary formation and evolution processes.
title Mass estimates of the young TOI-451 transiting planets: Multidimensional Gaussian Process on stellar spectroscopic and photometric signals
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2601.09438