© 2018 by Helen Giles - All opinions expressed are my own

Helen Giles

CHEOPS PhD Student

Observatoire de Genève

About Me

Originally from a town in the North West of England, I was fascinated with astronomy from a young age.
After attending a summer space school for three years, I independently studied for a GCSE in Astronomy during the last four months of my final year of high school.
Two years later, I achieved the necessary grades to attend the University of St Andrews in Scotland to study Astrophysics.

In St Andrews, I opted to enter into the second year - taking each astronomy course possible.
During the course of my degree I undertook two summer internships in exoplanet atmospheres and detection, with Christiane Helling in St Andrews and Chas Beichman in Pasadena.
Then for my final year Masters project, studying starspot lifetimes from Kepler data, was supervised by Raphaëlle Haywood and Andrew Collier Cameron.

After earning an integrated Masters degree in Astrophysics (1st class with Honours), I secured a PhD position at the Observatoire de Genève in Switzerland where I have continued my stellar activity work and further exoplanet discovery.


My Research

Fiery Sun


Whilst we understand sunspots extremely well, our knowledge of these magnetic regions on other stars is limited. And given we can't resolve stellar surfaces to the same degree as we can observe the solar surface, we need to extrapolate information from another source.

For my Masters' project (and now as part of my PhD) I successfully determined the lifetimes of starspots from photometry obtained from the Kepler mission, and how they depend on the stellar spectral type in collaboration with Raphaëlle Haywood and Andrew Collier Cameron.

For details, see the paper available on arXiv.


Exoplanet Discovery & Characterisation

In my role as the CHEOPS PhD student, I conduct the exoplanet discovery and radial velocity follow-up from publicly released data from the K2 mission - in collaboration with Exoplanet groups around Europe, the USA and Chile. Currently this has resulted in three planet discoveries (one from a summer internship, two during my PhD where one is still in the pipeline).

These tools and methods will be applied to the TESS mission when it releases its first set of data.

For details, see the papers for Kepler-1654 b, K2-140 b and EPIC248847494b available on arXiv.



Total Publications: 10 | Total Refereed: 9 | First Author: 3 | h-index: 5

Transiting planet candidate from K2 with the longest period

H.A.C. Giles, H.P. Osborn, S. Blanco-Cuaresma, C. Lovis, D. Bayliss, P. Eggenberger, A. Collier Cameron, M.H. Kristiansen, O. Turner, F. Bouchy, and S. Udry

Accepted to Astronomy & Astrophysics

An Earth-sized exoplanet with a Mercury-like composition

Santerne, A.; Brugger, B.; Armstrong, D.J.; Adibekyan, V.; Lillo-Box, J.; Gosselin, H.; Aguichine, A.; Almenara, J.-M.; Barrado, D.; Barros, S.C.C.; Bayliss, D.; Boisse, I.; Bonomo, A.S.; Bouchy, F.; Brown, D.J.A.; Deleuil, M.; Delgado Mena, E.; Demangeon, O.; Díaz, R.F.; Doyle, A.; Dumusque, X.; Faedi, F.; Faria, J. P.; Figueira, P.; Foxell, E.; Giles, H.A.C.; Hébrard, G.; Hojjatpanah, S.; Hobson, M.; Jackman, J.; King, G.; Kirk, J.; Lam, K.W.F.; Ligi, R.; Lovis, C.; Louden, T.; McCormac, J.; Mousis, O.; Neal, J.J.; Osborn, H.P.; Pepe, F.; Pollacco, D.; Santos, N.C.; Sousa, S.G.; Udry, S.; Vigan, A.

Nature Astronomy, Volume 2, 393-400 (2018)

An Accurate Mass Determination for Kepler-1655b, a Moderately Irradiated World with a Significant Volatile Envelope

Haywood, R.D.; Vanderburg, A.; Mortier, A.; Giles, H.A.C.; López-Morales, M.; Lopez, E.D.; Malavolta, L.; Charbonneau, D.; Collier Cameron, A.; Coughlin, J.L.; Dressing, C.D.; Nava, C.; Latham, D.W.; Dumusque, X.; Lovis, C.; Molinari, E.; Pepe, F.; Sozzetti, A.; Udry, S.; Bouchy, F.; Johnson, J.A.; Mayor, M.; Micela, G.; Phillips, D.; Piotto, G.; Rice, K.; Sasselov, D.; Ségransan, D.; Watson, C.; Affer, L.; Bonomo, A.S.; Buchhave, L.A.; Ciardi, D.R.; Fiorenzano, A.F.; Harutyunyan, A.

The Astronomical Journal, Volume 155, Issue 5, 203 (2018)

K2-140b - an eccentric 6.57 d transiting hot Jupiter in Virgo

Giles, H.A.C.; Bayliss, D.; Espinoza, N.; Brahm, R.; Blanco-Cuaresma, S.; Shporer, A.; Armstrong, D.; Lovis, C.; Udry, S.; Bouchy, F.; Marmier, M.; Jordán, A.; Bento, J.; Collier Cameron, A.; Sefako, R.; Cochran, W. D.; Rojas, F.; Rabus, M.; Jenkins, J.S.; Jones, M.; Pantoja, B.; Soto, M.; Jensen-Clem, R.; Duev, D.A.; Salama, M.; Riddle, R.; Baranec, C.; Law, N.M.

Monthly Notices of the Royal Astronomical Society, Volume 475:2, 1809-1818 (2018)

Validation and Initial Characterization of the Long-period Planet Kepler-1654 b

Beichman, C.A.; Giles, H.A.C.; Akeson, R.; Ciardi, D.; Christiansen, J.; Isaacson, H.; Marcy, G.M.; Sinukoff, E.; Greene, T.; Fortney, J.J.; Crossfield, I.; Hu, R.; Howard, A. W.; Petigura, E. A.; Knutson, H.A.

The Astronomical Journal, Volume 155, Issue 4, 158, 11, (2018)

Understanding Stellar Contamination in Exoplanet Transmission Spectra as an Essential Step in Small Planet Characterization

Apai, D.; Rackham, B.V.; Giampapa, M.S.; Angerhausen, D.; Teske, J.; Barstow, J.; Carone, L.; Cegla, H.; Domagal-Goldman, S.D.; Espinoza, N.; Giles, H.A.C.; Gully-Santiago, M.; Haywood, R.; Hu, R.; Jordan, A.; Kreidberg, L.; Line, M.; Llama, J.; López-Morales, M.; Marley, M.S.; de Wit, J.

White paper submitted to the NAS Committee on Exoplanet Science Strategy

A Kepler study of starspot lifetimes with respect to light-curve amplitude and spectral type

Giles, H.A.C.; Collier Cameron, A.; Haywood, R.D.

Monthly Notices of the Royal Astronomical Society, Volume 472:2, 1618-1627 (2017)

Ground-based photometry of the 21-day Neptune HD 106315c

Lendl, M.; Ehrenreich, D.; Turner, O. D.; Bayliss, D.; Blanco-Cuaresma, S.; Giles, H.; Bouchy, F.; Marmier, M.; Udry, S.

Astronomy & Astrophysics, Volume 603, L5 (2017)

Kepler-21b: A Rocky Planet Around a V = 8.25 Magnitude Star

López-Morales, M.; Haywood, R.D.; Coughlin, J.L.; Zeng, L.; Buchhave, L.A.; Giles, H.A.C.; Affer, L.; Bonomo, A.S.; Charbonneau, D.; Collier Cameron, A.; Consentino, R.; Dressing, C.D.; Dumusque, X.; Figueira, P.; Fiorenzano, A.F.M.; Harutyunyan, A.; Johnson, J.A.; Latham, D.W.; Lopez, E.D.; Lovis, C.; Malavolta, L.; Mayor, M.; Micela, G.; Molinari, E.; Mortier, A.; Motalebi, F.; Nascimbeni, V.; Pepe, F.; Phillips, D.F.; Piotto, G.; Pollacco, D.; Queloz, D.; Rice, K.; Sasselov, D.; Segransan, D.; Sozzetti, A.; Udry, S.; Vanderburg, A.; Watson, C.

The Astronomical Journal, Volume 152, Issue 6, 204 (2016)

Dust in brown dwarfs and extra-solar planets.
IV. Assessing TiO2 and SiO nucleation for cloud formation modelling

Lee, G.; Helling, Ch.; Giles, H.A.C.; Bromley, S.T.

Astronomy & Astrophysics, Volume 575, A11 (2015)


Talks & Posters


Cool Stars 20

31 July 2018

Starspots and Their Longer Lives on Cool Stars

An invited talk given at the 'Know thy Starspot, Know thy Star' splinter session at the 20th Cambridge Workshop on Cool Stars in Boston, Massachusetts (USA).

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Exoplanets II

2 July 2018

The Longest Period Transiting Planet Candidate from K2

A poster presented at the Exoplanets II conference in Cambridge, UK.


Know thy Star, Know thy Planet

12 October 2017

Determining Starspot Lifetimes from Photometry to Feed Models of Stellar Activity in Exoplanet RV Surveys

A talk given at the Know thy Star, Know thy Planet conference in Pasadena, California (USA).


CHEOPS 5th Science Workshop

24 July 2017

K2 Discoveries as Precursors for CHEOPS Follow-Up Candidates

A talk given at the 5th CHEOPS Science Workshop in Schloss Seggau, Austria.


Transiting Exoplanets

17 July 2017

EPIC 228735255b - A tale of an eccentric transiting hot Jupiter

A poster presented at the Transiting Exoplanet conference in Keele, UK.


UK Exoplanet Meeting 2017

16 March 2017

A Transit-Searching Pipeline for CHEOPS Candidates from Campaign 10 of K2

A poster presented at the 2017 UK Exoplanet Meeting in St Andrews, Scotland.

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UK Exoplanet Meeting 2017

16 March 2017

Determining starspot lifetimes from photometry to feed models of stellar activity in exoplanet RV surveys

A talk given at the 2017 UK Exoplanet Meeting in St Andrews, Scotland.


CHEOPS 4th Science Workshop

23 June 2016

“What's eating those starspots?” - Determining a Relationship Between Starspot Size and Their Decay Timescale With Respect to Stellar Spectral Type

A talk given at the 4th CHEOPS Science Workshop in Geneva, Switzerland.


Cool Stars 19

7 June 2016

“What's eating those starspots?” - Determining a Relationship Between Starspot Size and Their Decay Timescale With Respect to Stellar Spectral Type

A plenary talk given at the 19th Cambridge Workshop on Cool Stars in Uppsala, Sweden.

Contact Me

If you want to get in touch, I’d love to hear from you!
You can either send me an email (helen.giles[at]unige.ch) or use the contact form below!