The magnetic activity, winds and planets of young, cool stars

PhD Thesis


Nicholson, Belinda A.. 2018. The magnetic activity, winds and planets of young, cool stars. PhD Thesis Doctor of Philosophy. University of Southern Queensland. https://doi.org/10.26192/5f643970ce22a
Title

The magnetic activity, winds and planets of young, cool stars

TypePhD Thesis
Authors
AuthorNicholson, Belinda A.
SupervisorCarter, Bradley D.
Hussain, Gaitee A. J.
Brookshaw, Leigh
Vidotto, Aline A.
Institution of OriginUniversity of Southern Queensland
Qualification NameDoctor of Philosophy
Number of Pages86
Year2018
Digital Object Identifier (DOI)https://doi.org/10.26192/5f643970ce22a
Abstract

This thesis uses spectropolarimetry to observationally investigate the properties of dynamos and winds of young cool stars, and search for young planets. The techniques of Doppler Imaging and Zeeman Doppler Imaging were used to reconstruct the surface brightness and large-scale magnetic field morphologies of four low-mass weak-line T Tauri stars. The first sample consists of two solar mass stars of different ages, V1095 Sco (1 Myrs) and TWA 9A (10 Myrs). The second sample analysed consists of two 10 Myr old, M-type stars, TWA 25 (0.7 M⊙) and TWA 7 (0.4 M⊙). Taken together, the reconstructed brightness maps of these young cool stars show a wide variety in their morphologies, as do the reconstructed large-scale magnetic fields. These findings are in agreement with the results of the wider Magnetic Topologies of Young Stars and the Survival of close-in giant Exoplanets (MaTYSSE) large programme, of which this thesis is a part. The variations in radial velocity are examined for all four stars, using the brightness information where available to filter out activity jitter, improving the detection limits for close-in giant planets around these stars.

In addition to this investigation of pre-main sequence stellar dynamos and young planetary systems, a time series of magnetic field observations of the planet-hosting young star T Boötis spanning more than half a decade - the longest to date - is used to infer changes in the stellar wind, and the resulting potential impacts on the orbiting
planet.

In overall terms, this thesis demonstrates that spectropolarimetry is a valuable tool for understanding the magnetic dynamos of young cool stars, modelling stellar winds, and for searching for planets in the presence of stellar activity. In future, spectropolarimetry used as part of radial velocity surveys can advance our understanding of the early evolution of cool stars and their planetary systems.

Keywordsastronomy, young stars, magnetic fields, stellar winds
ANZSRC Field of Research 2020510109. Stellar astronomy and planetary systems
Byline AffiliationsComputational Engineering and Science Research Centre
Permalink -

https://research.usq.edu.au/item/q5022/the-magnetic-activity-winds-and-planets-of-young-cool-stars

Download files


Published Version
Nicholson_2018_whole.pdf
File access level: Anyone

  • 356
    total views
  • 153
    total downloads
  • 3
    views this month
  • 5
    downloads this month

Export as

Related outputs

HARPS radial velocity search for planets in the Scorpius-Centaurus association: A combination with the HARPS and SOPHIE young nearby stars (YNS) surveys
Grandjean, A., Lagrange, A.M., Meunier, N., Chauvin, G., Borgniet, S., Desidera, S., Galland, F., Kiefer, F., Messina, S., Iglesias, D., Nicholson, B., Pantoja, B., Rubini, P., Sedaghati, E., Sterzik, M. and Zicher, N.. 2023. "HARPS radial velocity search for planets in the Scorpius-Centaurus association: A combination with the HARPS and SOPHIE young nearby stars (YNS) surveys." Astronomy and Astrophysics: a European journal. 669. https://doi.org/10.1051/0004-6361/202141235
Revisiting K2-233 spectroscopic time-series with multidimensional Gaussian processes
Barragan, Oscar, Gillen, Edward, Aigrain, Suzanne, Meech, Annabella, Klein, Baptiste, Nielsen, Louise Dyregaard, Yu, Haochuan, O'Sullivan, Niamh K., Nicholson, Belinda A. and Lillo-Box, Jorge. 2023. "Revisiting K2-233 spectroscopic time-series with multidimensional Gaussian processes." Monthly Notices of the Royal Astronomical Society. 522 (3), pp. 3458-3471. https://doi.org/10.1093/mnras/stad1139
Sub-m s-1upper limits from a deep HARPS-N radial-velocity search for planets orbiting HD 166620 and HD 144579
John, A. Anna, Collier Cameron, A., Faria, J. P., Mortier, A., Wilson, T. G., Malavolta, L., Buchhave, L. A., Dumusque, X., Lopez-Morales, M., Haywood, R. D., Rice, K., Sozzetti, A., Latham, D. W., Udry, S., Pepe, F., Pinamonti, M., Vanderburg, A., Ghedina, A., Cosentino, R., ..., Poretti, E.. 2023. "Sub-m s-1upper limits from a deep HARPS-N radial-velocity search for planets orbiting HD 166620 and HD 144579." Monthly Notices of the Royal Astronomical Society. 525 (2), pp. 1687-1704. https://doi.org/10.1093/mnras/stad2381
Quasi-periodic Gaussian processes for stellar activity: From physical to kernel parameters
Nicholson, B. A. and Aigrain, S. 2022. "Quasi-periodic Gaussian processes for stellar activity: From physical to kernel parameters." Monthly Notices of the Royal Astronomical Society. 515 (4), pp. 5251-5266. https://doi.org/10.1093/mnras/stac2097
The Youngest Planet to Have a Spin-Orbit Alignment Measurement AU Mic b
Addison, Brett C., Horner, Jonathan, Wittenmyer, Robert A., Heitzmann, Alexis, Plavchan, Peter, Wright, Duncan J., Nicholson, Belinda A., Marshall, Jonathan P., Clark, Jake T., Gunther, Maximilian N., Kane, Stephen R., Hirano, Teruyuki, Wang, Songhu, Kielkopf, John, Shporer, Avi, Tinney, C. G., Zhang, Hui, Ballard, Sarah, Bedding, Timothy, ..., Wang, Xian-Yu. 2021. "The Youngest Planet to Have a Spin-Orbit Alignment Measurement AU Mic b." The Astronomical Journal. 162 (4), pp. 1-12. https://doi.org/10.3847/1538-3881/ac1685
The surface magnetic activity of the weak-line T Tauri stars TWA 7 and TWA 25
Nicholson, B. A., Hussain, G., Donati, J.-F., Wright, D., Folsom, C.P., Wittenmyer, R., Okumura, J. and Carter, B.D.. 2021. "The surface magnetic activity of the weak-line T Tauri stars TWA 7 and TWA 25." Monthly Notices of the Royal Astronomical Society. 504 (2), pp. 2461-2473. https://doi.org/10.1093/mnras/stab879
TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star
Addison, Brett C., Wright, Duncan J., Nicholson, Belinda A., Cale, Bryson, Mocnik, Teo, Huber, Daniel, Plavchan, Peter, Wittenmyer, Robert A., Vanderburg, Andrew, Chaplin, William J., Chontos, Ashley, Clark, Jake T., Eastman, Jason D., Ziegler, Carl, Brahm, Rafael, Carter, Bradley D., Clerte, Mathieu, Espinoza, Nestor, Horner, Jonathan, ..., Themeßl, Nathalie. 2021. "TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star." Monthly Notices of the Royal Astronomical Society. 502 (3), pp. 3704-3722. https://doi.org/10.1093/mnras/staa3960
MINERVA-Australis. I. Design, Commissioning, and First Photometric Results
Addison, Brett, Wright, Duncan J., Wittenmyer, Robert A., Horner, Jonathan, Mengel, Matthew W., Johns, Daniel, Marti, Connor, Nicholson, Belinda, Okumura, Jack, Bowler, Brendan, Crossfield, Ian, Kane, Stephen R., Kielkopf, John, Plavchan, Peter, Tinney, C.G., Zhang, Hui, Clark, Jake T., Clerte, Mathieu, Eastman, Jason D., ..., Carter, Bradley D.. 2019. "MINERVA-Australis. I. Design, Commissioning, and First Photometric Results." Publications of the Astronomical Society of the Pacific. 131 (1005), pp. 1-15. https://doi.org/10.1088/1538-3873/ab03aa
The gender balance of the Australian space research community: a snapshot from the 16th ASRC, 2016
Horner, Jonathan, Nicholson, Belinda, Cairns, Ann, Short, Wayne and Gorman, Alice. 2017. "The gender balance of the Australian space research community: a snapshot from the 16th ASRC, 2016." Short, Wayne and Cairns, Iver (ed.) 16th Australian Space Research Conference (ASRC 2016). Melbourne, Australia 26 - 28 Sep 2016 Sydney, Australia.
The surface magnetic activity of the weak-line T Tauri stars TWA 9Aand V1095 Sco
Nicholson, B. A., Hussain, G. A. J., Donati, J.-F., Folsom, C. P., Mengel, M., Carter, B. D. and Wright, D.. 2018. "The surface magnetic activity of the weak-line T Tauri stars TWA 9Aand V1095 Sco." Monthly Notices of the Royal Astronomical Society. 480 (2), pp. 1754-1766. https://doi.org/10.1093/mnras/sty1965
Temporal variability of the wind from the star τ Boötis
Nicholson, B. A., Vidotto, A. A., Mengel, M., Brookshaw, L., Carter, B., Petit, P., Marsden, S. C., Jeffers, S. V. and Fares, R.. 2016. "Temporal variability of the wind from the star τ Boötis." Monthly Notices of the Royal Astronomical Society. 459 (2), pp. 1907-1915. https://doi.org/10.1093/mnras/stw731
Winds of planet hosting stars
Nicholson, B. A., Mengel, M. W., Brookshaw, L., Vidotto, A. A., Carter, B. D., Marsden, S. C., Soutter, J., Waite, I. A. and Horner, J.. 2015. "Winds of planet hosting stars." Short, Wayne and Cairns, Iver (ed.) 14th Australian Space Research Conference (ASRC 2014). Adelaide, Australia 29 Sep - 01 Oct 2014 Sydney, Australia.