The HARPS search for southern extra-solar planets: XXXV. the interesting case of HD 41248: Stellar activity, no planets?

N. C. Santos; A. Mortier; J. P. Faria; X. Dumusque; V. Zh Adibekyan; E. Delgado-Mena; P. Figueira; L. Benamati; I. Boisse; D. Cunha; J. Gomes Da Silva; G. Lo Curto; C. Lovis; J. H.C. Martins; M. Mayor; C. Melo; M. Oshagh; F. Pepe; D. Queloz; A. Santerne; D. Segransan; A. Sozzetti; S. G. Sousa; S. Udry

doi:10.1051/0004-6361/201423808

The HARPS search for southern extra-solar planets: XXXV. the interesting case of HD 41248: Stellar activity, no planets?

N. C. Santos, A. Mortier, J. P. Faria, X. Dumusque, V. Zh Adibekyan, E. Delgado-Mena, P. Figueira, L. Benamati, I. Boisse, D. Cunha, J. Gomes Da Silva, G. Lo Curto, C. Lovis, J. H.C. Martins, M. Mayor, C. Melo, M. Oshagh, F. Pepe, D. Queloz, A. SanterneD. Segransan, A. Sozzetti, S. G. Sousa, S. Udry

Physics and Astronomy

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68 Citations (Scopus)

Abstract

Context. The search for planets orbiting metal-poor stars is of utmost importance for our understanding of planet formation models. However, no dedicated searches have been conducted so far for very low mass planets orbiting such objects. Only a few cases of low-mass planets orbiting metal-poor stars are thus known. Amongst these, HD 41248 is a metal-poor, solar-type star on the orbit of which a resonant pair of super-Earth-like planets has been announced. This detection was based on 62 radial velocity measurements obtained with the HARPS spectrograph (public data). Aims. We present a new planet search program that is using the HARPS spectrograph to search for Neptunes and super-Earths that orbit a sample of metal-poor FGK dwarfs. We then present a detailed analysis of 162 additional radial velocity measurements of HD 41248, obtained within this program, with the goal of confirming the existence of the proposed planetary system. Methods. We analysed the precise radial velocities, obtained with the HARPS spectrograph, together with several stellar activity diagnostics and line profile indicators. Results. A careful analysis shows no evidence for the planetary system. One of the signals, with a period of ∼25 days, is shown to be related to the rotational period of the star, and is clearly seen in some of the activity proxies. We were unable to convincingly retrieve the remaining signal (P ∼ 18 days) in the new dataset. Conclusions. We discuss possible causes for the complex (evolving) signals observed in the data of HD 41248, proposing that they might be explained by the appearance and disappearance of active regions on the surface of a star with strong differential rotation, or by a combination of the sparse data sampling and active region evolution.

Original language	English
Article number	A35
Journal	Astronomy and Astrophysics
Volume	566
DOIs	https://doi.org/10.1051/0004-6361/201423808
Publication status	Published - 1 Jun 2014

Bibliographical note

Funding Information:
We would like to thank N. Lanza for fruitful discussions. We acknowledge support from Fundação para a Ciência e a Tecnologia (FCT, Portugal) through FEDER funds in program COMPETE, as well as through national funds, in the form of grants reference PTDC/CTE-AST/120251/2010 (COMPETE reference FCOMP-01-0124-FEDER-019884), RECI/FIS-AST/0176/2012 (FCOMP-01-0124-FEDER-027493), and RECI/FIS-AST/0163/2012 (FCOMP-01-0124-FEDER-027492). This work was supported by the European Research Council/European Community under the FP7 through Starting Grant agreement number 239953. N.C.S. and P.F. were supported by FCT through the Investigador FCT contract references IF/00169/2012 and IF/01037/2013 and POPH/FSE (EC) by FEDER funding through the program Programa Operacional de Factores de Competitividade COMPETE. X. Dumusque was supported by the Swiss National Science Foundation. This work made use of the SIMBAD database.

Keywords

Planetary systems
Stars: abundances
Stars: activity
Stars: individual: HD 41248
Stars: solar-type
Surveys

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1051/0004-6361/201423808

Cite this

Santos, N. C., Mortier, A., Faria, J. P., Dumusque, X., Adibekyan, V. Z., Delgado-Mena, E., Figueira, P., Benamati, L., Boisse, I., Cunha, D., Gomes Da Silva, J., Lo Curto, G., Lovis, C., Martins, J. H. C., Mayor, M., Melo, C., Oshagh, M., Pepe, F., Queloz, D., ... Udry, S. (2014). The HARPS search for southern extra-solar planets: XXXV. the interesting case of HD 41248: Stellar activity, no planets? Astronomy and Astrophysics, 566, Article A35. https://doi.org/10.1051/0004-6361/201423808

@article{265a603568924a8fa11394ad8dffc028,

title = "The HARPS search for southern extra-solar planets: XXXV. the interesting case of HD 41248: Stellar activity, no planets?",

abstract = "Context. The search for planets orbiting metal-poor stars is of utmost importance for our understanding of planet formation models. However, no dedicated searches have been conducted so far for very low mass planets orbiting such objects. Only a few cases of low-mass planets orbiting metal-poor stars are thus known. Amongst these, HD 41248 is a metal-poor, solar-type star on the orbit of which a resonant pair of super-Earth-like planets has been announced. This detection was based on 62 radial velocity measurements obtained with the HARPS spectrograph (public data). Aims. We present a new planet search program that is using the HARPS spectrograph to search for Neptunes and super-Earths that orbit a sample of metal-poor FGK dwarfs. We then present a detailed analysis of 162 additional radial velocity measurements of HD 41248, obtained within this program, with the goal of confirming the existence of the proposed planetary system. Methods. We analysed the precise radial velocities, obtained with the HARPS spectrograph, together with several stellar activity diagnostics and line profile indicators. Results. A careful analysis shows no evidence for the planetary system. One of the signals, with a period of ∼25 days, is shown to be related to the rotational period of the star, and is clearly seen in some of the activity proxies. We were unable to convincingly retrieve the remaining signal (P ∼ 18 days) in the new dataset. Conclusions. We discuss possible causes for the complex (evolving) signals observed in the data of HD 41248, proposing that they might be explained by the appearance and disappearance of active regions on the surface of a star with strong differential rotation, or by a combination of the sparse data sampling and active region evolution.",

keywords = "Planetary systems, Stars: abundances, Stars: activity, Stars: individual: HD 41248, Stars: solar-type, Surveys",

author = "Santos, {N. C.} and A. Mortier and Faria, {J. P.} and X. Dumusque and Adibekyan, {V. Zh} and E. Delgado-Mena and P. Figueira and L. Benamati and I. Boisse and D. Cunha and {Gomes Da Silva}, J. and {Lo Curto}, G. and C. Lovis and Martins, {J. H.C.} and M. Mayor and C. Melo and M. Oshagh and F. Pepe and D. Queloz and A. Santerne and D. Segransan and A. Sozzetti and Sousa, {S. G.} and S. Udry",

note = "Funding Information: We would like to thank N. Lanza for fruitful discussions. We acknowledge support from Funda{\c c}{\~a}o para a Ci{\^e}ncia e a Tecnologia (FCT, Portugal) through FEDER funds in program COMPETE, as well as through national funds, in the form of grants reference PTDC/CTE-AST/120251/2010 (COMPETE reference FCOMP-01-0124-FEDER-019884), RECI/FIS-AST/0176/2012 (FCOMP-01-0124-FEDER-027493), and RECI/FIS-AST/0163/2012 (FCOMP-01-0124-FEDER-027492). This work was supported by the European Research Council/European Community under the FP7 through Starting Grant agreement number 239953. N.C.S. and P.F. were supported by FCT through the Investigador FCT contract references IF/00169/2012 and IF/01037/2013 and POPH/FSE (EC) by FEDER funding through the program Programa Operacional de Factores de Competitividade COMPETE. X. Dumusque was supported by the Swiss National Science Foundation. This work made use of the SIMBAD database.",

year = "2014",

month = jun,

day = "1",

doi = "10.1051/0004-6361/201423808",

language = "English",

volume = "566",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

}

Santos, NC, Mortier, A, Faria, JP, Dumusque, X, Adibekyan, VZ, Delgado-Mena, E, Figueira, P, Benamati, L, Boisse, I, Cunha, D, Gomes Da Silva, J, Lo Curto, G, Lovis, C, Martins, JHC, Mayor, M, Melo, C, Oshagh, M, Pepe, F, Queloz, D, Santerne, A, Segransan, D, Sozzetti, A, Sousa, SG & Udry, S 2014, 'The HARPS search for southern extra-solar planets: XXXV. the interesting case of HD 41248: Stellar activity, no planets?', Astronomy and Astrophysics, vol. 566, A35. https://doi.org/10.1051/0004-6361/201423808

TY - JOUR

T1 - The HARPS search for southern extra-solar planets

T2 - XXXV. the interesting case of HD 41248: Stellar activity, no planets?

AU - Santos, N. C.

AU - Mortier, A.

AU - Faria, J. P.

AU - Dumusque, X.

AU - Adibekyan, V. Zh

AU - Delgado-Mena, E.

AU - Figueira, P.

AU - Benamati, L.

AU - Boisse, I.

AU - Cunha, D.

AU - Gomes Da Silva, J.

AU - Lo Curto, G.

AU - Lovis, C.

AU - Martins, J. H.C.

AU - Mayor, M.

AU - Melo, C.

AU - Oshagh, M.

AU - Pepe, F.

AU - Queloz, D.

AU - Santerne, A.

AU - Segransan, D.

AU - Sozzetti, A.

AU - Sousa, S. G.

AU - Udry, S.

N1 - Funding Information: We would like to thank N. Lanza for fruitful discussions. We acknowledge support from Fundação para a Ciência e a Tecnologia (FCT, Portugal) through FEDER funds in program COMPETE, as well as through national funds, in the form of grants reference PTDC/CTE-AST/120251/2010 (COMPETE reference FCOMP-01-0124-FEDER-019884), RECI/FIS-AST/0176/2012 (FCOMP-01-0124-FEDER-027493), and RECI/FIS-AST/0163/2012 (FCOMP-01-0124-FEDER-027492). This work was supported by the European Research Council/European Community under the FP7 through Starting Grant agreement number 239953. N.C.S. and P.F. were supported by FCT through the Investigador FCT contract references IF/00169/2012 and IF/01037/2013 and POPH/FSE (EC) by FEDER funding through the program Programa Operacional de Factores de Competitividade COMPETE. X. Dumusque was supported by the Swiss National Science Foundation. This work made use of the SIMBAD database.

PY - 2014/6/1

Y1 - 2014/6/1

N2 - Context. The search for planets orbiting metal-poor stars is of utmost importance for our understanding of planet formation models. However, no dedicated searches have been conducted so far for very low mass planets orbiting such objects. Only a few cases of low-mass planets orbiting metal-poor stars are thus known. Amongst these, HD 41248 is a metal-poor, solar-type star on the orbit of which a resonant pair of super-Earth-like planets has been announced. This detection was based on 62 radial velocity measurements obtained with the HARPS spectrograph (public data). Aims. We present a new planet search program that is using the HARPS spectrograph to search for Neptunes and super-Earths that orbit a sample of metal-poor FGK dwarfs. We then present a detailed analysis of 162 additional radial velocity measurements of HD 41248, obtained within this program, with the goal of confirming the existence of the proposed planetary system. Methods. We analysed the precise radial velocities, obtained with the HARPS spectrograph, together with several stellar activity diagnostics and line profile indicators. Results. A careful analysis shows no evidence for the planetary system. One of the signals, with a period of ∼25 days, is shown to be related to the rotational period of the star, and is clearly seen in some of the activity proxies. We were unable to convincingly retrieve the remaining signal (P ∼ 18 days) in the new dataset. Conclusions. We discuss possible causes for the complex (evolving) signals observed in the data of HD 41248, proposing that they might be explained by the appearance and disappearance of active regions on the surface of a star with strong differential rotation, or by a combination of the sparse data sampling and active region evolution.

AB - Context. The search for planets orbiting metal-poor stars is of utmost importance for our understanding of planet formation models. However, no dedicated searches have been conducted so far for very low mass planets orbiting such objects. Only a few cases of low-mass planets orbiting metal-poor stars are thus known. Amongst these, HD 41248 is a metal-poor, solar-type star on the orbit of which a resonant pair of super-Earth-like planets has been announced. This detection was based on 62 radial velocity measurements obtained with the HARPS spectrograph (public data). Aims. We present a new planet search program that is using the HARPS spectrograph to search for Neptunes and super-Earths that orbit a sample of metal-poor FGK dwarfs. We then present a detailed analysis of 162 additional radial velocity measurements of HD 41248, obtained within this program, with the goal of confirming the existence of the proposed planetary system. Methods. We analysed the precise radial velocities, obtained with the HARPS spectrograph, together with several stellar activity diagnostics and line profile indicators. Results. A careful analysis shows no evidence for the planetary system. One of the signals, with a period of ∼25 days, is shown to be related to the rotational period of the star, and is clearly seen in some of the activity proxies. We were unable to convincingly retrieve the remaining signal (P ∼ 18 days) in the new dataset. Conclusions. We discuss possible causes for the complex (evolving) signals observed in the data of HD 41248, proposing that they might be explained by the appearance and disappearance of active regions on the surface of a star with strong differential rotation, or by a combination of the sparse data sampling and active region evolution.

KW - Planetary systems

KW - Stars: abundances

KW - Stars: activity

KW - Stars: individual: HD 41248

KW - Stars: solar-type

KW - Surveys

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DO - 10.1051/0004-6361/201423808

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SN - 0004-6361

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JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

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ER -

The HARPS search for southern extra-solar planets: XXXV. the interesting case of HD 41248: Stellar activity, no planets?

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

Access to Document

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