Abstract
Aims. We report the discovery and characterisation of the transiting mini-Neptune HD 207496 b (TOI-1099) as part of a large programme that aims to characterise naked core planets. Methods. We obtained HARPS spectroscopic observations, one ground-based transit, and high-resolution imaging which we combined with the TESS photometry to confirm and characterise the TESS candidate and its host star. Results. The host star is an active early K dwarf with a mass of 0.80 ± 0.04 M⊙, a radius of 0.769 ± 0.026 R⊙, and a G magnitude of 8. We found that the host star is young, ~0.52 Gyr, allowing us to gain insight into planetary evolution. We derived a planetary mass of 6.1 ± 1.6 M⊕, a planetary radius of 2.25 ± 0.12 R⊕, and a planetary density of ρp = 3.27-0.91+0.97 g cm-3. Conclusions. From internal structure modelling of the planet, we conclude that the planet has either a water-rich envelope, a gas-rich envelope, or a mixture of both. We have performed evaporation modelling of the planet. If we assume the planet has a gas-rich envelope, we find that the planet has lost a significant fraction of its envelope and its radius has shrunk. Furthermore, we estimate it will lose all its remaining gaseous envelope in ~0.52 Gyr. Otherwise, the planet could have already lost all its primordial gas and is now a bare ocean planet. Further observations of its possible atmosphere and/or mass-loss rate would allow us to distinguish between these two hypotheses. Such observations would determine if the planet remains above the radius gap or if it will shrink and be below the gap.
| Original language | English (US) |
|---|---|
| Article number | A4 |
| Journal | Astronomy and Astrophysics |
| Volume | 673 |
| DOIs | |
| State | Published - May 1 2023 |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
Keywords
- Methods: data analysis
- Planets and satellites: composition
- Planets and satellites: detection
- Planets and satellites: fundamental parameters
- Techniques: photometric
- Techniques: radial velocities
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In: Astronomy and Astrophysics, Vol. 673, A4, 01.05.2023.
Research output: Contribution to journal › Article › peer-review
TY - JOUR
T1 - The young mini-Neptune HD 207496b that is either a naked core or on the verge of becoming one
AU - Barros, S. C.C.
AU - Demangeon, O. D.S.
AU - Armstrong, D. J.
AU - Delgado Mena, E.
AU - Acuña, L.
AU - Fernández Fernández, J.
AU - Deleuil, M.
AU - Collins, K. A.
AU - Howell, S. B.
AU - Ziegler, C.
AU - Adibekyan, V.
AU - Sousa, S. G.
AU - Stassun, K. G.
AU - Grieves, N.
AU - Lillo-Box, J.
AU - Hellier, C.
AU - Wheatley, P. J.
AU - Briceño, C.
AU - Collins, K. I.
AU - Hawthorn, F.
AU - Hoyer, S.
AU - Jenkins, J.
AU - Law, N.
AU - Mann, A. W.
AU - Matson, R. A.
AU - Mousis, O.
AU - Nielsen, L. D.
AU - Osborn, A.
AU - Osborn, H.
AU - Paegert, M.
AU - Papini, R.
AU - Ricker, G. R.
AU - Rudat, A. A.
AU - Santos, N. C.
AU - Seager, S.
AU - Stockdale, C.
AU - Strøm, P. A.
AU - Twicken, J. D.
AU - Udry, S.
AU - Wang, G.
AU - Vanderspek, R.
AU - Winn, J. N.
N1 - Funding Information: This study is based on observations collected at the European Southern Observatory under ESO programme (NCORES large program, ID 1102.C-0249, PI: D. Armstrong) This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This work has made use of data from the European Space Agency (ESA) mission ( https://www.cosmos.esa.int/web/gaia ), processed by the Gaia Data Processing and Analysis Consortium ( https://www.cosmos.esa.int/web/gaia/dpac/consortium ). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work was supported by FCT – Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 – Programa Operacional Competitividade e Internacionalização by these grants: UIDB/04434/2020; UIDP/04434/2020, 2022.06962.PTDC. The research leading to these results has received funding from the European Research Council through the grant agreement 101052347 (FIERCE). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by FCT. E.D.M. acknowledges the support from FCT through Stimulus FCT contract 2021.01294.CEECIND D.J.A. is supported by UKRI through the STFC (ST/R00384X/1) and EPSRC (EP/X027562/1). J.L.-B. acknowledges financial support received from “la Caixa” Foundation (ID 100010434) and from the European Union’s Horizon 2020 research and innovation programme under the Marie Slodowska-Curie grant agreement No 847648, with fellowship code LCF/BQ/PI20/11760023. This research has also been partly funded by the Spanish State Research Agency (AEI) Projects No.PID2019-107061GB-C61. This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA’s Science Mission Directorate. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This work makes use of observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. This research has made use of the Exoplanet Follow-up Observation Program (ExoFOP; DOI: 10.26134/ExoFOP5 ) website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Some of the observations in the paper made use of the High-Resolution Imaging instrument Zorro obtained under Gemini LLP Proposal Number: GN/S-2021A-LP-105. Zorro was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Zorro was mounted on the Gemini North (and/or South) telescope of the international Gemini Observatory, a program of NSF’s OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). F.H. is supported by an STFC studentship. A.O. is funded by an STFC studentship. J.F.F. acknowledges support from an STFC studentship under grant ST/W507908/1. P.J.W. acknowledges support from STFC under the consolidated grant ST/T000406/1. S.H. acknowledges CNES funding through the grant 837319 This work has been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation under grants 51NF40-182901 and 51NF40-2056. Funding Information: This study is based on observations collected at the European Southern Observatory under ESO programme (NCORES large program, ID 1102.C-0249, PI: D. Armstrong) This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This work has made use of data from the European Space Agency (ESA) mission (https://www.cosmos.esa.int/web/gaia), processed by the Gaia Data Processing and Analysis Consortium (https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work was supported by FCT - Fundação para a Cincia e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização by these grants: UIDB/04434/2020; UIDP/04434/2020, 2022.06962.PTDC. The research leading to these results has received funding from the European Research Council through the grant agreement 101052347 (FIERCE). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by FCT. E.D.M. acknowledges the support from FCT through Stimulus FCT contract 2021.01294.CEECIND D.J.A. is supported by UKRI through the STFC (ST/R00384X/1) and EPSRC (EP/X027562/1). J.L.-B. acknowledges financial support received from "la Caixa" Foundation (ID 100010434) and from the European Union's Horizon 2020 research and innovation programme under the Marie Slodowska-Curie grant agreement No 847648, with fellowship code LCF/BQ/PI20/11760023. This research has also been partly funded by the Spanish State Research Agency (AEI) Projects No.PID2019-107061GB-C61. This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA's Science Mission Directorate. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This work makes use of observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. This research has made use of the Exoplanet Follow-up Observation Program (ExoFOP; https://doi.org/10.26134/ExoFOP5) website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Some of the observations in the paper made use of the High-Resolution Imaging instrument Zorro obtained under Gemini LLP Proposal Number: GN/S-2021A-LP-105. Zorro was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Zorro was mounted on the Gemini North (and/or South) telescope of the international Gemini Observatory, a program of NSF's OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). F.H. is supported by an STFC studentship. A.O. is funded by an STFC studentship. J.F.F. acknowledges support from an STFC studentship under grant ST/W507908/1. P.J.W. acknowledges support from STFC under the consolidated grant ST/T000406/1. S.H. acknowledges CNES funding through the grant 837319 This work has been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation under grants 51NF40-182901 and 51NF40-2056. Publisher Copyright: © 2023 EDP Sciences. All rights reserved.
PY - 2023/5/1
Y1 - 2023/5/1
N2 - Aims. We report the discovery and characterisation of the transiting mini-Neptune HD 207496 b (TOI-1099) as part of a large programme that aims to characterise naked core planets. Methods. We obtained HARPS spectroscopic observations, one ground-based transit, and high-resolution imaging which we combined with the TESS photometry to confirm and characterise the TESS candidate and its host star. Results. The host star is an active early K dwarf with a mass of 0.80 ± 0.04 M⊙, a radius of 0.769 ± 0.026 R⊙, and a G magnitude of 8. We found that the host star is young, ~0.52 Gyr, allowing us to gain insight into planetary evolution. We derived a planetary mass of 6.1 ± 1.6 M⊕, a planetary radius of 2.25 ± 0.12 R⊕, and a planetary density of ρp = 3.27-0.91+0.97 g cm-3. Conclusions. From internal structure modelling of the planet, we conclude that the planet has either a water-rich envelope, a gas-rich envelope, or a mixture of both. We have performed evaporation modelling of the planet. If we assume the planet has a gas-rich envelope, we find that the planet has lost a significant fraction of its envelope and its radius has shrunk. Furthermore, we estimate it will lose all its remaining gaseous envelope in ~0.52 Gyr. Otherwise, the planet could have already lost all its primordial gas and is now a bare ocean planet. Further observations of its possible atmosphere and/or mass-loss rate would allow us to distinguish between these two hypotheses. Such observations would determine if the planet remains above the radius gap or if it will shrink and be below the gap.
AB - Aims. We report the discovery and characterisation of the transiting mini-Neptune HD 207496 b (TOI-1099) as part of a large programme that aims to characterise naked core planets. Methods. We obtained HARPS spectroscopic observations, one ground-based transit, and high-resolution imaging which we combined with the TESS photometry to confirm and characterise the TESS candidate and its host star. Results. The host star is an active early K dwarf with a mass of 0.80 ± 0.04 M⊙, a radius of 0.769 ± 0.026 R⊙, and a G magnitude of 8. We found that the host star is young, ~0.52 Gyr, allowing us to gain insight into planetary evolution. We derived a planetary mass of 6.1 ± 1.6 M⊕, a planetary radius of 2.25 ± 0.12 R⊕, and a planetary density of ρp = 3.27-0.91+0.97 g cm-3. Conclusions. From internal structure modelling of the planet, we conclude that the planet has either a water-rich envelope, a gas-rich envelope, or a mixture of both. We have performed evaporation modelling of the planet. If we assume the planet has a gas-rich envelope, we find that the planet has lost a significant fraction of its envelope and its radius has shrunk. Furthermore, we estimate it will lose all its remaining gaseous envelope in ~0.52 Gyr. Otherwise, the planet could have already lost all its primordial gas and is now a bare ocean planet. Further observations of its possible atmosphere and/or mass-loss rate would allow us to distinguish between these two hypotheses. Such observations would determine if the planet remains above the radius gap or if it will shrink and be below the gap.
KW - Methods: data analysis
KW - Planets and satellites: composition
KW - Planets and satellites: detection
KW - Planets and satellites: fundamental parameters
KW - Techniques: photometric
KW - Techniques: radial velocities
UR - http://www.scopus.com/inward/record.url?scp=85156209760&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85156209760&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/202245741
DO - 10.1051/0004-6361/202245741
M3 - Article
AN - SCOPUS:85156209760
SN - 0004-6361
VL - 673
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A4
ER -