Zobrazeno 1 - 10
of 2 106
pro vyhledávání: '"Lehmann, L."'
Autor:
Donati, J. -F., Cristofari, P. I., Lehmann, L. T., Moutou, C., Alencar, S. H. P., Bouvier, J., Arnold, L., Delfosse, X., Artigau, E., Cook, N., Kóspál, Á., Ménard, F., Baruteau, C., Takami, M., Cabrit, S., Hébrard, G., Doyon, R., team, the SPIRou science
In this paper we report near-infrared observations of the classical T Tauri star TW Hya with the SPIRou high-resolution spectropolarimeter and velocimeter at the 3.6-m Canada-France-Hawaii Telescope in 2019, 2020, 2021 and 2022. By applying Least-Squ
Externí odkaz:
http://arxiv.org/abs/2405.04461
Autor:
Bellotti, S., Morin, J., Lehmann, L. T., Petit, P., Hussain, G. A. J., Donati, J. -F., Folsom, C. P., Carmona, A., Martioli, E., Klein, B., Fouque, P., Moutou, C., Alencar, S., Artigau, E., Boisse, I., Bouchy, F., Bouvier, J., Cook, N. J., Delfosse, X., Doyon, R., Hebrard, G.
Dynamo models of stellar magnetic fields for partly and fully convective stars are guided by observational constraints. Zeeman-Doppler imaging has revealed a variety of magnetic field geometries and, for fully convective stars in particular, a dichot
Externí odkaz:
http://arxiv.org/abs/2403.08590
Autor:
Lehmann, L. T., Donati, J. -F., Fouque, P., Moutou, C., Bellotti, S., Delfosse, X., Petit, P., Carmona, A., Morin, J., Vidotto, A. A., consortium, the SLS
In this paper, we study six slowly rotating mid-to-late M~dwarfs (rotation period $P_{\mathrm{rot}} \approx 40-190\,\mathrm{dy}$) by analysing spectropolarimetric data collected with SPIRou at the Canada-France-Hawaii Telescope as part of the SPIRou
Externí odkaz:
http://arxiv.org/abs/2311.05039
Autor:
Cristofari, P. I., Donati, J. -F., Moutou, C., Lehmann, L. T., Charpentier, P., Fouqué, P., Folsom, C. P., Masseron, T., Carmona, A., Delfosse, X., Petit, P., Artigau, E., Cook, N. J., consortium, the SLS
We present the results of an analysis aimed at probing the small-scale magnetic fields of M dwarfs observed with SPIRou, the nIR high-resolution spectro-polarimeter installed at the Canada-France-Hawaii Telescope, in the context of the SPIRou Legacy
Externí odkaz:
http://arxiv.org/abs/2310.08386
Autor:
Donati, J. -F., Lehmann, L. T., Cristofari, P. I., Fouqué, P., Moutou, C., Charpentier, P., Ould-Elhkim, M., Carmona, A., Delfosse, X., Artigau, E., Alencar, S. H. P., Cadieux, C., Arnold, L., Petit, P., Morin, J., Forveille, T., Cloutier, R., Doyon, R., Hébrard, G., collaboration, the SLS
We present near-infrared spectropolarimetric observations of a sample of 43 weakly- to moderately-active M dwarfs, carried with SPIRou at the Canada-France-Hawaii Telescope in the framework of the SPIRou Legacy Survey from early 2019 to mid 2022. We
Externí odkaz:
http://arxiv.org/abs/2307.14190
Autor:
Bellotti, S., Morin, J., Lehmann, L. T., Folsom, C. P., Hussain, G. A. J., Petit, P., Donati, J. F., Lavail, A., Carmona, A., Martioli, E., Zaire, B. Romano, Alecian, E., Moutou, C., Fouque, P., Alencar, S., Artigau, E., Boisse, I., Bouchy, F., Cadieux, C., Cloutier, R., Cook, N., Delfosse, X., Doyon, R., Hebrard, G., Kochukhov, O., Wade, G.
Publikováno v:
A&A 676, A56 (2023)
One manifestation of dynamo action on the Sun is the 22-yr magnetic cycle, exhibiting a polarity reversal and a periodic conversion between poloidal and toroidal fields. For M dwarfs, several authors claim evidence of activity cycles from photometry
Externí odkaz:
http://arxiv.org/abs/2307.01016
Autor:
Donati, J. -F., Cristofari, P. I., Finociety, B., Klein, B., Moutou, C., Gaidos, E., Cadieux, C., Artigau, E., Correia, A. C. M., Boué, G., Cook, N. J., Carmona, A., Lehmann, L. T., Bouvier, J., Martioli, E., Morin, J., Fouqué, P., Delfosse, X., Royon, R., Hébrard, G., Alencar, S. H. P., Laskar, J., Arnold, L., Petit, P., Kospal, A., Vidotto, A., Folsom, C. P., collaboration, the SLS
In this paper we present an analysis of near-infrared spectropolarimetric and velocimetric data of the young M dwarf AU Mic, collected with SPIRou at the Canada-France-Hawaii telescope from 2019 to 2022, mostly within the SPIRou Legacy Survey. With t
Externí odkaz:
http://arxiv.org/abs/2304.09642
Autor:
Fouqué, P., Martioli, E., Donati, J. -F., Lehmann, L. T., Zaire, B., Bellotti, S., Gaidos, E., Morin, J., Moutou, C., Petit, P., Alencar, S. H. P., Arnold, L., Artigau, É., Cang, T. -Q., Carmona, A., Cook, N. J., Cortés-Zuleta, P., Cristofari, P. I., Delfosse, X., Doyon, R., Hébrard, G., Malo, L., Reylé, C., Usher, C.
Publikováno v:
A&A 672, A52 (2023)
Context. The rotation period of stars is an important parameter along with mass, radius, effective temperature. It is an essential parameter for any radial velocity monitoring, as stellar activity can mimic the presence of a planet at the stellar rot
Externí odkaz:
http://arxiv.org/abs/2302.03377
Autor:
Lehmann, L. T., Donati, J. -F.
Insights on stellar surface large-scale magnetic field topologies are usually drawn by applying Zeeman-Doppler-Imaging (ZDI) to the observed spectropolarimetric time series. However, ZDI requires experience for reliable results to be reached and is b
Externí odkaz:
http://arxiv.org/abs/2205.15647
Autor:
Lund, K., Jardine, M., Lehmann, L. T., Mackay, D. H., See, V., Vidotto, A. A., Donati, J. -F., Fares, R., Folsom, C. P., Jeffers, S. V., Marsden, S. C., Morin, J., Petit, P.
Helicity is a fundamental property of a magnetic field but to date it has only been possible to observe its evolution in one star - the Sun. In this paper we provide a simple technique for mapping the large-scale helicity density across the surface o
Externí odkaz:
http://arxiv.org/abs/2001.11749