Skip to main content
Home
Department Of Physics text logo
  • Research
    • Our research
    • Our research groups
    • Our research in action
    • Research funding support
    • Summer internships for undergraduates
  • Study
    • Undergraduates
    • Postgraduates
  • Engage
    • For alumni
    • For business
    • For schools
    • For the public
Menu
Stellar_flare_hits_HD_189733_b_(artist's_impression)

This artist's impression shows the hot Jupiter HD 189733b, as it passes in front of its parent star, as the latter is flaring, driving material away from the planet. The escaping atmosphere is seen silhouetted against the starlight. The surface of the star, which is around 80% the mass of the Sun, is based on observations of the Sun from NASA's Solar Dynamics Observatory.

Credit: NASA, ESA, L. Calçada, Solar Dynamics Observatory

Prof Suzanne Aigrain

Professor of Astrophysics

Research theme

  • Astronomy and astrophysics
  • Exoplanets and planetary physics

Sub department

  • Astrophysics

Research groups

  • Exoplanets and Stellar Physics
Suzanne.Aigrain@physics.ox.ac.uk
Telephone: 01865 (2)73339
Denys Wilkinson Building, room 762
Stars & Planets @ Oxford research group website
  • About
  • Publications

Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometry

Astronomy and Astrophysics EDP Sciences 626 (2019) A38

Authors:

AF Lanza, Y Netto, AS Bonomo, H Parviainen, A Valio, Suzanne Aigrain

Abstract:

Context. The study of young Sun-like stars is fundamental to understanding the magnetic activity and rotational evolution of the Sun. Space-borne photometry by the Kepler telescope provides unprecedented datasets to investigate these phenomena in Sun-like stars.

Aims. We present a new analysis of the entire Kepler photometric time series of the moderately young Sun-like star Kepler-17 accompanied by a transiting hot Jupiter.

Methods. We applied a maximum-entropy spot model to the long-cadence out-of-transit photometry of the target to derive maps of the starspot filling factor versus the longitude and the time. These maps are compared to the spots occulted during transits to validate our reconstruction and derive information on the latitudes of the starspots.

Results. We find two main active longitudes on the photosphere of Kepler-17, one of which has a lifetime of at least ∼1400 days although with a varying level of activity. The latitudinal differential rotation is of solar type, that is, with the equator rotating faster than the poles. We estimate a minimum relative amplitude ΔΩ/Ω between ∼0.08 ± 0.05 and 0.14 ± 0.05, our determination being affected by the finite lifetime of individual starspots and depending on the adopted spot model parameters. We find marginal evidence of a short-term intermittent activity cycle of ∼48 days and an indication of a longer cycle of 400−600 days characterized by an equatorward migration of the mean latitude of the spots as in the Sun. The rotation of Kepler-17 is likely to be significantly affected by the tides raised by its massive close-by planet.

Conclusions. We confirm the reliability of maximum-entropy spot models to map starspots in young active stars and characterize the activity and differential rotation of this young Sun-like planetary host.

More details from the publisher
Details from ORA
More details
Details from ArXiV

The rotation of low mass stars at 30 Myr in the cluster NGC 3766

Proceedings of the International Astronomical Union Cambridge University Press (CUP) 15:S354 (2019) 200-203

Authors:

Julia Roquette, Jerome Bouvier, Estelle Moraux, Herve Bouy, Jonathan Irwin, Suzanne Aigrain, Régis Lachaume
More details from the publisher
More details

The Kepler Smear Campaign: Light curves for 102 Very Bright Stars

(2019)

Authors:

Benjamin JS Pope, Guy R Davies, Keith Hawkins, Timothy R White, Amalie Stokholm, Allyson Bieryla, David W Latham, Madeline Lucey, Conny Aerts, Suzanne Aigrain, Victoria Antoci, Timothy R Bedding, Dominic M Bowman, Douglas A Caldwell, Ashley Chontos, Gilbert A Esquerdo, Daniel Huber, Paula Jofre, Simon J Murphy, Timothy van Reeth, Victor Silva Aguirre, Jie Yu
More details from the publisher

Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometry

(2019)

Authors:

AF Lanza, Y Netto, AS Bonomo, H Parviainen, A Valio, S Aigrain
More details from the publisher

Planets, candidates, and binaries from the CoRoT/Exoplanet programme: the CoRoT transit catalogue

Astronomy and Astrophysics Springer Verlag (2018)

Authors:

M Deleuil, S Aigrain, C Moutou, J Cabrera, F Bouchy, HJ Deeg, J-M Almenara, G Hébrard, A Santerne, R Alonso, AS Bonomo, P Bordé, S Csizmadia, A Erikson, M Fridlund, D Gandolfi, E Guenther, T Guillot, P Guterman, S Grziwa, A Hatzes, A Léger, T Mazeh, A Ofir, M Ollivier, M Pätzold, H Parviainen, H Rauer, D Rouan, J Schneider, R Titz-Weider, B Tingley, J Weingrill

Abstract:

We provide the catalogue of all transit-like features, including false alarms, detected by the CoRoT exoplanet teams in the 177 454 light curves of the mission. All these detections have been re-analysed with the same softwares so that to ensure their homogeneous analysis. Although the vetting process involves some human evaluation, it also involves a simple binary flag system over basic tests: detection significance, presence of a secondary, difference between odd and even depths, colour dependence, V-shape transit, and duration of the transit. We also gathered the information from the large accompanying ground-based programme carried out on the planet candidates and checked how useful the flag system could have been at the vetting stage of the candidates. In total, we identified and separated 824 false alarms of various kind, 2269 eclipsing binaries among which 616 are contact binaries and 1653 are detached ones, 37 planets and brown dwarfs, and 557 planet candidates. For the planet candidates, the catalogue gives not only their transit parameters but also the products of their light curve modelling, together with a summary of the outcome of follow-up observations when carried out and their current status. Among the planet candidates whose nature remains unresolved, we estimate that 8 +/- 3 planets are still to be identified. We derived planet and brown dwarf occurrences and confirm disagreements with Kepler estimates: small-size planets with orbital period less than ten days are underabundant by a factor of three in the CoRoT fields whereas giant planets are overabundant by a factor of two. These preliminary results would however deserve further investigations using the recently released CoRoT light curves that are corrected of the various instrumental effects and a homogeneous analysis of the stellar populations observed by the two missions.
More details
More details from the publisher
Details from ORA
More details
Details from ArXiV

Pagination

  • First page First
  • Previous page Prev
  • …
  • Page 19
  • Page 20
  • Page 21
  • Page 22
  • Current page 23
  • Page 24
  • Page 25
  • Page 26
  • Page 27
  • …
  • Next page Next
  • Last page Last

Footer Menu

  • Contact us
  • Giving to the Dept of Physics
  • Work with us
  • Media

User account menu

  • Log in

Follow us

FIND US

Clarendon Laboratory,

Parks Road,

Oxford,

OX1 3PU

CONTACT US

Tel: +44(0)1865272200

University of Oxfrod logo Department Of Physics text logo
IOP Juno Champion logo Athena Swan Silver Award logo

© University of Oxford - Department of Physics

Cookies | Privacy policy | Accessibility statement

Built by: Versantus

  • Home
  • Research
  • Study
  • Engage
  • Our people
  • News & Comment
  • Events
  • Our facilities & services
  • About us
  • Current students
  • Staff intranet