Characterization of the HD 108236 system with CHEOPS and TESS confirmation of a fifth transiting planet

S. Hoyer; A. Bonfanti; A. Leleu; L. Acuña; L.M. Serrano; M. Deleuil; A. Bekkelien; C. Broeg; H.-G. Florén; D. Queloz; T.G. Wilson; S.G. Sousa; M.J. Hooton; V. Adibekyan; Y. Alibert; R. Alonso; G. Anglada; J. Asquier; T. Bárczy; D. Barrado; S.C.C. Barros; W. Baumjohann; M. Beck; T. Beck; W. Benz; N. Billot; F. Biondi; X. Bonfils; A. Brandeker; J. Cabrera; S. Charnoz; A. Collier Cameron; S. Csizmadia; M.B. Davies; L. Delrez; O.D.S. Demangeon; B.-O. Demory; D. Ehrenreich; A. Erikson; A. Fortier; L. Fossati; M. Fridlund; D. Gandolfi; M. Gillon; M. Güdel; N. Hara; K. Heng; K.G. Isaak; J.M. Jenkins; L.L. Kiss; J. Laskar; D.W. Latham; A. Lecavelier Des Etangs; M. Lendl; C. Lovis; A. Luntzer; D. Magrin; P.F.L. Maxted; V. Nascimbeni; G. Olofsson; R. Ottensamer; I. Pagano; E. Pallé; C.M. Persson; G. Peter; D. Piazza; G. Piotto; D. Pollacco; R. Ragazzoni; N. Rando; H. Rauer; I. Ribas; G.R. Ricker; S. Salmon; N.C. Santos; G. Scandariato; S. Seager; D. Ségransan; A.E. Simon; A.M.S. Smith; M. Steller; G.M. Szabó; N. Thomas; J.D. Twicken; S. Udry; V. Van Grootel; R.K. Vanderspek; N.A. Walton; K. Westerdorff; J.N. Winn

doi:10.1051/0004-6361/202243720

Characterization of the HD 108236 system with CHEOPS and TESS confirmation of a fifth transiting planet

S. Hoyer^*, A. Bonfanti, A. Leleu, L. Acuña, L.M. Serrano, M. Deleuil, A. Bekkelien, C. Broeg, H.-G. Florén, D. Queloz, T.G. Wilson, S.G. Sousa, M.J. Hooton, V. Adibekyan, Y. Alibert, R. Alonso, G. Anglada, J. Asquier, T. Bárczy, D. BarradoS.C.C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, F. Biondi, X. Bonfils, A. Brandeker, J. Cabrera, S. Charnoz, A. Collier Cameron, S. Csizmadia, M.B. Davies, L. Delrez, O.D.S. Demangeon, B.-O. Demory, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, N. Hara, K. Heng, K.G. Isaak, J.M. Jenkins, L.L. Kiss, J. Laskar, D.W. Latham, A. Lecavelier Des Etangs, M. Lendl, C. Lovis, A. Luntzer, D. Magrin, P.F.L. Maxted, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, C.M. Persson, G. Peter, D. Piazza, G. Piotto, D. Pollacco, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G.R. Ricker, S. Salmon, N.C. Santos, G. Scandariato, S. Seager, D. Ségransan, A.E. Simon, A.M.S. Smith, M. Steller, G.M. Szabó, N. Thomas, J.D. Twicken, S. Udry, V. Van Grootel, R.K. Vanderspek, N.A. Walton, K. Westerdorff, J.N. Winn

^*Corresponding author for this work

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

Abstract

Context. The HD 108236 system was first announced with the detection of four small planets based on TESS data. Shortly after, the transit of an additional planet with a period of 29.54 d was serendipitously detected by CHEOPS. In this way, HD 108236 (V = 9.2) became one of the brightest stars known to host five small transiting planets (R_p < 3 R_⊕).

Aims. We characterize the planetary system by using all the data available from CHEOPS and TESS space missions. We use the flexible pointing capabilities of CHEOPS to follow up the transits of all the planets in the system, including the fifth transiting body.

Methods. After updating the host star parameters by using the results from Gaia eDR3, we analyzed 16 and 43 transits observed by CHEOPS and TESS, respectively, to derive the planets' physical and orbital parameters. We carried out a timing analysis of the transits of each of the planets of HD 108236 to search for the presence of transit timing variations.

Results. We derived improved values for the radius and mass of the host star (R∗ = 0.876 ± 0.007 R₀ and M∗ = 0.867_-0.046^+0.047M☉). We confirm the presence of the fifth transiting planet f in a 29.54 d orbit. Thus, the HD 108236 system consists of five planets of R_b = 1.587±0.028, R_c = 2.122±0.025, R_d = 2.629 ± 0.031, R_e = 3.008 ± 0.032, and R_f = 1.89 ± 0.04 [R_⊕]. We refine the transit ephemeris for each planet and find no significant transit timing variations for planets c, d, and e. For planets b and f, instead, we measure significant deviations on their transit times (up to 22 and 28 min, respectively) with a non-negligible dispersion of 9.6 and 12.6 min in their time residuals.

Conclusions. We confirm the presence of planet f and find no significant evidence for a potential transiting planet in a 10.9 d orbital period, as previously suggested. Further monitoring of the transits, particularly for planets b and f, would confirm the presence of the observed transit time variations. HD 108236 thus becomes a key multi-planetary system for the study of formation and evolution processes. The reported precise results on the planetary radii - together with a profuse RV monitoring - will allow for an accurate characterization of the internal structure of these planets.

Original language	English
Article number	A117
Number of pages	25
Journal	Astronomy and Astrophysics
Volume	668
DOIs	https://doi.org/10.1051/0004-6361/202243720
Publication status	Published - 13 Dec 2022

Keywords

Planetary systems
Planets and satellites: detection
Planets and satellites: fundamental parameters
Planets and satellites: individual: HD 108236
Planets and satellites: individual: TOI 1233

Access to Document

10.1051/0004-6361/202243720Licence: CC BY

Hoyer_2022_AA_Chararacterization-HD-108236_CC
Copyright © S. Hoyer et al. 2022. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Final published version, 15.8 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

Cite this

Hoyer, S., Bonfanti, A., Leleu, A., Acuña, L., Serrano, L. M., Deleuil, M., Bekkelien, A., Broeg, C., Florén, H.-G., Queloz, D., Wilson, T. G., Sousa, S. G., Hooton, M. J., Adibekyan, V., Alibert, Y., Alonso, R., Anglada, G., Asquier, J., Bárczy, T., ... Winn, J. N. (2022). Characterization of the HD 108236 system with CHEOPS and TESS confirmation of a fifth transiting planet. Astronomy and Astrophysics, 668, Article A117. https://doi.org/10.1051/0004-6361/202243720

@article{4ffd0f3c5b464a07b8dd223dadb92a17,

title = "Characterization of the HD 108236 system with CHEOPS and TESS confirmation of a fifth transiting planet",

abstract = "Context. The HD 108236 system was first announced with the detection of four small planets based on TESS data. Shortly after, the transit of an additional planet with a period of 29.54 d was serendipitously detected by CHEOPS. In this way, HD 108236 (V = 9.2) became one of the brightest stars known to host five small transiting planets (Rp < 3 R⊕). Aims. We characterize the planetary system by using all the data available from CHEOPS and TESS space missions. We use the flexible pointing capabilities of CHEOPS to follow up the transits of all the planets in the system, including the fifth transiting body. Methods. After updating the host star parameters by using the results from Gaia eDR3, we analyzed 16 and 43 transits observed by CHEOPS and TESS, respectively, to derive the planets' physical and orbital parameters. We carried out a timing analysis of the transits of each of the planets of HD 108236 to search for the presence of transit timing variations. Results. We derived improved values for the radius and mass of the host star (R∗ = 0.876 ± 0.007 R0 and M∗ = 0.867-0.046+0.047M☉). We confirm the presence of the fifth transiting planet f in a 29.54 d orbit. Thus, the HD 108236 system consists of five planets of Rb = 1.587±0.028, Rc = 2.122±0.025, Rd = 2.629 ± 0.031, Re = 3.008 ± 0.032, and Rf = 1.89 ± 0.04 [R⊕]. We refine the transit ephemeris for each planet and find no significant transit timing variations for planets c, d, and e. For planets b and f, instead, we measure significant deviations on their transit times (up to 22 and 28 min, respectively) with a non-negligible dispersion of 9.6 and 12.6 min in their time residuals. Conclusions. We confirm the presence of planet f and find no significant evidence for a potential transiting planet in a 10.9 d orbital period, as previously suggested. Further monitoring of the transits, particularly for planets b and f, would confirm the presence of the observed transit time variations. HD 108236 thus becomes a key multi-planetary system for the study of formation and evolution processes. The reported precise results on the planetary radii - together with a profuse RV monitoring - will allow for an accurate characterization of the internal structure of these planets.",

keywords = "Planetary systems, Planets and satellites: detection, Planets and satellites: fundamental parameters, Planets and satellites: individual: HD 108236, Planets and satellites: individual: TOI 1233",

author = "S. Hoyer and A. Bonfanti and A. Leleu and L. Acu{\~n}a and L.M. Serrano and M. Deleuil and A. Bekkelien and C. Broeg and H.-G. Flor{\'e}n and D. Queloz and T.G. Wilson and S.G. Sousa and M.J. Hooton and V. Adibekyan and Y. Alibert and R. Alonso and G. Anglada and J. Asquier and T. B{\'a}rczy and D. Barrado and S.C.C. Barros and W. Baumjohann and M. Beck and T. Beck and W. Benz and N. Billot and F. Biondi and X. Bonfils and A. Brandeker and J. Cabrera and S. Charnoz and {Collier Cameron}, A. and S. Csizmadia and M.B. Davies and L. Delrez and O.D.S. Demangeon and B.-O. Demory and D. Ehrenreich and A. Erikson and A. Fortier and L. Fossati and M. Fridlund and D. Gandolfi and M. Gillon and M. G{\"u}del and N. Hara and K. Heng and K.G. Isaak and J.M. Jenkins and L.L. Kiss and J. Laskar and D.W. Latham and {Lecavelier Des Etangs}, A. and M. Lendl and C. Lovis and A. Luntzer and D. Magrin and P.F.L. Maxted and V. Nascimbeni and G. Olofsson and R. Ottensamer and I. Pagano and E. Pall{\'e} and C.M. Persson and G. Peter and D. Piazza and G. Piotto and D. Pollacco and R. Ragazzoni and N. Rando and H. Rauer and I. Ribas and G.R. Ricker and S. Salmon and N.C. Santos and G. Scandariato and S. Seager and D. S{\'e}gransan and A.E. Simon and A.M.S. Smith and M. Steller and G.M. Szab{\'o} and N. Thomas and J.D. Twicken and S. Udry and {Van Grootel}, V. and R.K. Vanderspek and N.A. Walton and K. Westerdorff and J.N. Winn",

note = "Funding: SH gratefully acknowledges CNES funding through the grant 837319. The authors acknowledge support from the Swiss NCCR PlanetS and the Swiss National Science Foundation. LMS gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 {\textquoteleft}Gaseous or rocky? Unveiling the nature of small worlds{\textquoteright}. This project was supported by the CNES. This work was also partially supported by a grant from the Simons Foundation (PI Queloz, grant number 327127). ACC and TW acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. S.G.S. acknowledges support from FCT through FCT contract nr. CEECIND/00826/2018 and POPH/FSE (EC). YA and MJH acknowledge the support of the Swiss National Fund under grant 200020_172746. We acknowledge support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grants ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R, MDM-2017-0737 Unidad de Excelencia Maria de Maeztu-Centro de Astrobiolog{\'i}a (INTA-CSIC), as well as the support of the Generalitat de Catalunya/CERCA programme. The MOC activities have been supported by the ESA contract No. 4000124370. S.C.C.B. acknowledges support from FCT through FCT contracts nr. IF/01312/2014/CP1215/CT0004. XB, SC, DG, MF and JL acknowledge their role as ESA-appointed CHEOPS science team members. ABr was supported by the SNSA. ACC acknowledges support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Li{\`e}ge through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. L.D. is an F.R.S.-FNRS Postdoctoral Researcher. This work was supported by FCT – Funda{\c c}{\~a}o para a Ci{\^e}ncia e a Tecnologia through national funds and by FEDER through COMPETE2020 – Programa Operacional Competitividade e Internacionalizac{\~a}o by these grants: UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 & POCI-01-0145-FEDER-028953, PTDC/FIS-AST/28987/2017 & POCI-01-0145-FEDER-028987, O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through FCT. B.-O.D. acknowledges support from the Swiss National Science Foundation (PP00P2-190080). This project has received funding from the European Research Council (ERC) under the European Union{\textquoteright}s Horizon 2020 research and innovation programme (project FOUR ACES. grant agreement No 724427). It has also been carried out in the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). D.E. acknowledges financial support from the Swiss National Science Foundation for project 200021_200726. M.F. and C.M.P. gratefully acknowledge the support of the Swedish National Space Agency (DNR 65/19, 174/18). D.G. gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 “Gaseousor rocky? Unveiling the nature of small worlds”. M.G. is an F.R.S.-FNRS Senior Research Associate. KGI is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme. She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection for the programme. This work was granted access to the HPC resources of MesoPSL financed by the Rgion {\^I}le-de-France and the project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme Investissements d{\textquoteright}Avenir supervised by the Agence Nationale pour la Recherche. M.L. acknowledges support of the Swiss National Science Foundation under grant number PCEFP2_194576. P.M. acknowledges support from STFC research grant number ST/M001040/1. G.Sc., G.Pi., I.Pa., L.Bo., V.Na. and R.Ra. acknowledge the funding support from Italian Space Agency (ASI) regulated by “Accordo ASI-INAF n. 2013-016-R.0 del 9 luglio 2013 e integrazione del 9 luglio 2015 CHEOPS Fasi A/B/C”. I.R.I. acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant PGC2018-098153-B-C33, as well as the support of the Generalitat de Catalunya/CERCA programme. S.S. has received funding from the EuropeanResearch Council (ERC) under the European Union{\textquoteright}s Horizon 2020 research and innovation program (grant agreement No 833925, project STAREX). Gy.M.Sz. acknowledges the support of the Hungarian National Research, Development and Innovation Office (NKFIH) grant K-125015, a PRODEX Institute Agreement between the ELTE E{\"o}tv{\"o}s Lor{\'a}nd University and the European Space Agency (ESA-D/SCI-LE-2021-0025), the Lend{\"u}let LP2018-7/2021 grant of the Hungarian Academy of Science and the support of the city of Szombathely. V.V.G. is an F.R.S-FNRS Research Associate. N.A.W. acknowledges UKSA grant ST/R004838/1. This research has made use of computing facilities operated by CeSAM data center at LAM, Marseille, France. We also thank J.C. Meunier and J.C. Lamber for the support provided in the use of these facilities. Software: We gratefully acknowledge the open-source software which made this work possible: astropy (Astropy Collaboration 2013, 2018), ipython (P{\'e}rez & Granger 2007), numpy (Harris et al. 2020), scipy (Jones et al. 2001), matplotlib (Hunter 2007), jupyter (Kluyver et al. 2016).",

year = "2022",

month = dec,

day = "13",

doi = "10.1051/0004-6361/202243720",

language = "English",

volume = "668",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP SCIENCES S A",

}

Hoyer, S, Bonfanti, A, Leleu, A, Acuña, L, Serrano, LM, Deleuil, M, Bekkelien, A, Broeg, C, Florén, H-G, Queloz, D, Wilson, TG, Sousa, SG, Hooton, MJ, Adibekyan, V, Alibert, Y, Alonso, R, Anglada, G, Asquier, J, Bárczy, T, Barrado, D, Barros, SCC, Baumjohann, W, Beck, M, Beck, T, Benz, W, Billot, N, Biondi, F, Bonfils, X, Brandeker, A, Cabrera, J, Charnoz, S, Collier Cameron, A, Csizmadia, S, Davies, MB, Delrez, L, Demangeon, ODS, Demory, B-O, Ehrenreich, D, Erikson, A, Fortier, A, Fossati, L, Fridlund, M, Gandolfi, D, Gillon, M, Güdel, M, Hara, N, Heng, K, Isaak, KG, Jenkins, JM, Kiss, LL, Laskar, J, Latham, DW, Lecavelier Des Etangs, A, Lendl, M, Lovis, C, Luntzer, A, Magrin, D, Maxted, PFL, Nascimbeni, V, Olofsson, G, Ottensamer, R, Pagano, I, Pallé, E, Persson, CM, Peter, G, Piazza, D, Piotto, G, Pollacco, D, Ragazzoni, R, Rando, N, Rauer, H, Ribas, I, Ricker, GR, Salmon, S, Santos, NC, Scandariato, G, Seager, S, Ségransan, D, Simon, AE, Smith, AMS, Steller, M, Szabó, GM, Thomas, N, Twicken, JD, Udry, S, Van Grootel, V, Vanderspek, RK, Walton, NA, Westerdorff, K & Winn, JN 2022, 'Characterization of the HD 108236 system with CHEOPS and TESS confirmation of a fifth transiting planet', Astronomy and Astrophysics, vol. 668, A117. https://doi.org/10.1051/0004-6361/202243720

TY - JOUR

T1 - Characterization of the HD 108236 system with CHEOPS and TESS confirmation of a fifth transiting planet

AU - Hoyer, S.

AU - Bonfanti, A.

AU - Leleu, A.

AU - Acuña, L.

AU - Serrano, L.M.

AU - Deleuil, M.

AU - Bekkelien, A.

AU - Broeg, C.

AU - Florén, H.-G.

AU - Queloz, D.

AU - Wilson, T.G.

AU - Sousa, S.G.

AU - Hooton, M.J.

AU - Adibekyan, V.

AU - Alibert, Y.

AU - Alonso, R.

AU - Anglada, G.

AU - Asquier, J.

AU - Bárczy, T.

AU - Barrado, D.

AU - Barros, S.C.C.

AU - Baumjohann, W.

AU - Beck, M.

AU - Beck, T.

AU - Benz, W.

AU - Billot, N.

AU - Biondi, F.

AU - Bonfils, X.

AU - Brandeker, A.

AU - Cabrera, J.

AU - Charnoz, S.

AU - Collier Cameron, A.

AU - Csizmadia, S.

AU - Davies, M.B.

AU - Delrez, L.

AU - Demangeon, O.D.S.

AU - Demory, B.-O.

AU - Ehrenreich, D.

AU - Erikson, A.

AU - Fortier, A.

AU - Fossati, L.

AU - Fridlund, M.

AU - Gandolfi, D.

AU - Gillon, M.

AU - Güdel, M.

AU - Hara, N.

AU - Heng, K.

AU - Isaak, K.G.

AU - Jenkins, J.M.

AU - Kiss, L.L.

AU - Laskar, J.

AU - Latham, D.W.

AU - Lecavelier Des Etangs, A.

AU - Lendl, M.

AU - Lovis, C.

AU - Luntzer, A.

AU - Magrin, D.

AU - Maxted, P.F.L.

AU - Nascimbeni, V.

AU - Olofsson, G.

AU - Ottensamer, R.

AU - Pagano, I.

AU - Pallé, E.

AU - Persson, C.M.

AU - Peter, G.

AU - Piazza, D.

AU - Piotto, G.

AU - Pollacco, D.

AU - Ragazzoni, R.

AU - Rando, N.

AU - Rauer, H.

AU - Ribas, I.

AU - Ricker, G.R.

AU - Salmon, S.

AU - Santos, N.C.

AU - Scandariato, G.

AU - Seager, S.

AU - Ségransan, D.

AU - Simon, A.E.

AU - Smith, A.M.S.

AU - Steller, M.

AU - Szabó, G.M.

AU - Thomas, N.

AU - Twicken, J.D.

AU - Udry, S.

AU - Van Grootel, V.

AU - Vanderspek, R.K.

AU - Walton, N.A.

AU - Westerdorff, K.

AU - Winn, J.N.

N1 - Funding: SH gratefully acknowledges CNES funding through the grant 837319. The authors acknowledge support from the Swiss NCCR PlanetS and the Swiss National Science Foundation. LMS gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 ‘Gaseous or rocky? Unveiling the nature of small worlds’. This project was supported by the CNES. This work was also partially supported by a grant from the Simons Foundation (PI Queloz, grant number 327127). ACC and TW acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. S.G.S. acknowledges support from FCT through FCT contract nr. CEECIND/00826/2018 and POPH/FSE (EC). YA and MJH acknowledge the support of the Swiss National Fund under grant 200020_172746. We acknowledge support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grants ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R, MDM-2017-0737 Unidad de Excelencia Maria de Maeztu-Centro de Astrobiología (INTA-CSIC), as well as the support of the Generalitat de Catalunya/CERCA programme. The MOC activities have been supported by the ESA contract No. 4000124370. S.C.C.B. acknowledges support from FCT through FCT contracts nr. IF/01312/2014/CP1215/CT0004. XB, SC, DG, MF and JL acknowledge their role as ESA-appointed CHEOPS science team members. ABr was supported by the SNSA. ACC acknowledges support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Liège through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. L.D. is an F.R.S.-FNRS Postdoctoral Researcher. 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 Internacionalizacão by these grants: UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 & POCI-01-0145-FEDER-028953, PTDC/FIS-AST/28987/2017 & POCI-01-0145-FEDER-028987, O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through FCT. B.-O.D. acknowledges support from the Swiss National Science Foundation (PP00P2-190080). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES. grant agreement No 724427). It has also been carried out in the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). D.E. acknowledges financial support from the Swiss National Science Foundation for project 200021_200726. M.F. and C.M.P. gratefully acknowledge the support of the Swedish National Space Agency (DNR 65/19, 174/18). D.G. gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 “Gaseousor rocky? Unveiling the nature of small worlds”. M.G. is an F.R.S.-FNRS Senior Research Associate. KGI is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme. She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection for the programme. This work was granted access to the HPC resources of MesoPSL financed by the Rgion Île-de-France and the project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme Investissements d’Avenir supervised by the Agence Nationale pour la Recherche. M.L. acknowledges support of the Swiss National Science Foundation under grant number PCEFP2_194576. P.M. acknowledges support from STFC research grant number ST/M001040/1. G.Sc., G.Pi., I.Pa., L.Bo., V.Na. and R.Ra. acknowledge the funding support from Italian Space Agency (ASI) regulated by “Accordo ASI-INAF n. 2013-016-R.0 del 9 luglio 2013 e integrazione del 9 luglio 2015 CHEOPS Fasi A/B/C”. I.R.I. acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant PGC2018-098153-B-C33, as well as the support of the Generalitat de Catalunya/CERCA programme. S.S. has received funding from the EuropeanResearch Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No 833925, project STAREX). Gy.M.Sz. acknowledges the support of the Hungarian National Research, Development and Innovation Office (NKFIH) grant K-125015, a PRODEX Institute Agreement between the ELTE Eötvös Loránd University and the European Space Agency (ESA-D/SCI-LE-2021-0025), the Lendület LP2018-7/2021 grant of the Hungarian Academy of Science and the support of the city of Szombathely. V.V.G. is an F.R.S-FNRS Research Associate. N.A.W. acknowledges UKSA grant ST/R004838/1. This research has made use of computing facilities operated by CeSAM data center at LAM, Marseille, France. We also thank J.C. Meunier and J.C. Lamber for the support provided in the use of these facilities. Software: We gratefully acknowledge the open-source software which made this work possible: astropy (Astropy Collaboration 2013, 2018), ipython (Pérez & Granger 2007), numpy (Harris et al. 2020), scipy (Jones et al. 2001), matplotlib (Hunter 2007), jupyter (Kluyver et al. 2016).

PY - 2022/12/13

Y1 - 2022/12/13

N2 - Context. The HD 108236 system was first announced with the detection of four small planets based on TESS data. Shortly after, the transit of an additional planet with a period of 29.54 d was serendipitously detected by CHEOPS. In this way, HD 108236 (V = 9.2) became one of the brightest stars known to host five small transiting planets (Rp < 3 R⊕). Aims. We characterize the planetary system by using all the data available from CHEOPS and TESS space missions. We use the flexible pointing capabilities of CHEOPS to follow up the transits of all the planets in the system, including the fifth transiting body. Methods. After updating the host star parameters by using the results from Gaia eDR3, we analyzed 16 and 43 transits observed by CHEOPS and TESS, respectively, to derive the planets' physical and orbital parameters. We carried out a timing analysis of the transits of each of the planets of HD 108236 to search for the presence of transit timing variations. Results. We derived improved values for the radius and mass of the host star (R∗ = 0.876 ± 0.007 R0 and M∗ = 0.867-0.046+0.047M☉). We confirm the presence of the fifth transiting planet f in a 29.54 d orbit. Thus, the HD 108236 system consists of five planets of Rb = 1.587±0.028, Rc = 2.122±0.025, Rd = 2.629 ± 0.031, Re = 3.008 ± 0.032, and Rf = 1.89 ± 0.04 [R⊕]. We refine the transit ephemeris for each planet and find no significant transit timing variations for planets c, d, and e. For planets b and f, instead, we measure significant deviations on their transit times (up to 22 and 28 min, respectively) with a non-negligible dispersion of 9.6 and 12.6 min in their time residuals. Conclusions. We confirm the presence of planet f and find no significant evidence for a potential transiting planet in a 10.9 d orbital period, as previously suggested. Further monitoring of the transits, particularly for planets b and f, would confirm the presence of the observed transit time variations. HD 108236 thus becomes a key multi-planetary system for the study of formation and evolution processes. The reported precise results on the planetary radii - together with a profuse RV monitoring - will allow for an accurate characterization of the internal structure of these planets.

AB - Context. The HD 108236 system was first announced with the detection of four small planets based on TESS data. Shortly after, the transit of an additional planet with a period of 29.54 d was serendipitously detected by CHEOPS. In this way, HD 108236 (V = 9.2) became one of the brightest stars known to host five small transiting planets (Rp < 3 R⊕). Aims. We characterize the planetary system by using all the data available from CHEOPS and TESS space missions. We use the flexible pointing capabilities of CHEOPS to follow up the transits of all the planets in the system, including the fifth transiting body. Methods. After updating the host star parameters by using the results from Gaia eDR3, we analyzed 16 and 43 transits observed by CHEOPS and TESS, respectively, to derive the planets' physical and orbital parameters. We carried out a timing analysis of the transits of each of the planets of HD 108236 to search for the presence of transit timing variations. Results. We derived improved values for the radius and mass of the host star (R∗ = 0.876 ± 0.007 R0 and M∗ = 0.867-0.046+0.047M☉). We confirm the presence of the fifth transiting planet f in a 29.54 d orbit. Thus, the HD 108236 system consists of five planets of Rb = 1.587±0.028, Rc = 2.122±0.025, Rd = 2.629 ± 0.031, Re = 3.008 ± 0.032, and Rf = 1.89 ± 0.04 [R⊕]. We refine the transit ephemeris for each planet and find no significant transit timing variations for planets c, d, and e. For planets b and f, instead, we measure significant deviations on their transit times (up to 22 and 28 min, respectively) with a non-negligible dispersion of 9.6 and 12.6 min in their time residuals. Conclusions. We confirm the presence of planet f and find no significant evidence for a potential transiting planet in a 10.9 d orbital period, as previously suggested. Further monitoring of the transits, particularly for planets b and f, would confirm the presence of the observed transit time variations. HD 108236 thus becomes a key multi-planetary system for the study of formation and evolution processes. The reported precise results on the planetary radii - together with a profuse RV monitoring - will allow for an accurate characterization of the internal structure of these planets.

KW - Planetary systems

KW - Planets and satellites: detection

KW - Planets and satellites: fundamental parameters

KW - Planets and satellites: individual: HD 108236

KW - Planets and satellites: individual: TOI 1233

U2 - 10.1051/0004-6361/202243720

DO - 10.1051/0004-6361/202243720

M3 - Article

SN - 0004-6361

VL - 668

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A117

ER -

Characterization of the HD 108236 system with CHEOPS and TESS confirmation of a fifth transiting planet

Abstract

Keywords

Access to Document

Fingerprint

Projects

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

Cite this