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BetaPic

Observing BetaPic and Exoplanets from Antarctica

- T. Guillot -

Discovery and study of exoplanetary systems with the ASTEP telescope in Antarctica during the polar winter

2½ hours of observation of Beta Pic with ASTEP (red) and the Hubble Space Telescope (blue) showing the ~30 min pulsations of the star. The ASTEP observations cover several months, nearly continuously while the much more accurate HST observations are limit 2½ hours of observation of Beta Pic with ASTEP (red) and the Hubble Space Telescope (blue) showing the ~30 min pulsations of the star. The ASTEP observations cover several months, nearly continuously while the much more accurate HST observations are limited to about 2 hours every couple of months [From Mékarnia et al. 2017]

Academy 3 highlight

The BetaPic project provides unprecedented observations that help us better understand exoplanets and planet formation. It involves a variety of expertise from electronics, operations in extremely cold environments, optics, data analysis and astrophysics.

The project

Exoplanets are planets around stars other than the Sun. Their characterization is one of the major goals of Astronomy, on the quest for Life in the Universe. The French/Italian Concordia base, at 3200m elevation in the middle of the Antarctic continent is a unique vantage point for Astronomy and particularly for the observation of exoplanets. In 2009, our team built ASTEP (Antarctic Search for Transiting Extrasolar Planets), a 40 cm automatic telescope that is able to operate continuously in the extreme southern Antarctic winter, under temperatures that can reach -80°C. The nearly-continuous 3 month-long night represents a considerable advantage to study exoplanets, in particular to examine changes in the light they reflect towards us as they move around their star.

In 2016, our team joined an international campaign to observe an iconic system: the young star Beta Pic. Beta Pic is the first star known to possess both a disk of dust where planets may form, and a planet, called Beta Pic b. The star is also pulsating. In 2017, the planet Beta Pic b passed, for the first time in 18 years, extremely close to its star, enabling the detection of moons or rings, expected in such a system but never detected unambiguously in any exoplanet.

We thus observed Beta Pic and its planet continuously during the 2017 and 2018 polar winters with the ASTEP telescope. We obtained a unique set of light curves of both high accuracy and long duration that revealed 31 pulsation modes of the star, of which only 3 were previously known. The analysis of the data covering years 2017 and 2018 is still ongoing. We hosted an international workshop on Beta Pic science in September 2018 at the Observatoire de la Côte d’Azur, gathering astronomers from institutes all over the world.

Beta Pic, star of the Antarctic sky. Poster for the Nice Beta Pic workshop, Sept. 2018 Beta Pic, star of the Antarctic sky. Poster for the Nice Beta Pic workshop, Sept. 2018

The +

This project has allowed the complete pulsation modes of the Beta Pic star to be observed for the first time, and permitted the discovery of a new planet - called Beta Pic c - in the Beta Pic system.

What’s next?

The ASTEP telescope is pursuing its observations of stars with candidate exoplanets such as those discovered by the NASA TESS space mission. Thanks to the support of Academy 3, the project has been funded by the French polar Agency up to 2022. We will develop new cameras with increased sensitivity that could provide simultaneous observations in the red and in the blue. The system should permit the discovery of small planets around red dwarf stars and characterize these systems more efficiently than ever before.

Project information

Scientific domain Astronomy, Planetary Science Theme Optical Observations	Key words Exoplanets, Telescopes, Antarctic
Total budget 214 k€ including: 20 k€ from Academie 3	Students inolved MEURISSE Geoffroy (M2) DERSON Etienne (M2)
Partner laboratories LAGRANGE, UCA OCA, UCA IPEV IPAG, OSUG University of Birmingham European Space Agency (ESA) International collaboration TRIAUD Amaury, University of Birmingham CROUZET Nicolas, ESA KALAS Paul, WANG Jason, Berkeley University KENWORTHY Matthew, Leiden University	Project members GUILLOT Tristan MÉKARNIA Djamel ABE Lyu AGABI Karim SCHMIDER François Xavier

Tristan Guillot

LAGRANGE, UCA

Project valorization

Publications:

Mékarnia, D., E. Chapellier, T. Guillot, L. Abe, A. Agabi, Y. De Pra, F.-X. Schmider, K. Zwintz, K. B. Stevenson, J. J. Wang, A.-M. Lagrange, L. Bigot, N. Crouzet, Y. Fanteï-Caujolle, J.-M. Christille, and P. Kalas, The δ Scuti pulsations of β Pictoris as observed by ASTEP from Antarctica. Astronomy and Astrophysics 608, L6 (2017).
Crouzet, N., E. Chapellier, T. Guillot, D. Mékarnia, A. Agabi, Y. Fanteï-Caujolle, L. Abe, J.-P. Rivet, F.-X. Schmider, F. Fressin, E. Bondoux, Z. Challita, C. Pouzenc, F. Valbousquet, D. Bayliss, S. Bonhomme, J.-B. Daban, C. Gouvret, and A. Blazit, Four winters of photometry with ASTEP South at Dome C, Antarctica. Astronomy and Astrophysics 619, A116 (2018). 10.1051/0004-6361/201732565
Lagrange, A., Meunier, N., Rubini, P. et al. Evidence for an additional planet in the β Pictoris system. Nat Astron 3, 1135–1142 (2019). https://doi.org/10.1038/s41550-019-0857-1
Zwintz, K., Reese, D. R., Neiner, C., Pigulski, A., Kuschnig, R., Müllner, M., Zieba, S., Abe, L., Guillot, T., Handler, G., Kenworthy, M., Stuik, R., Moffat, A. F. J., Popowicz, A., Rucinski, S. M., Wade, G. A., Weiss, W. W., Bailey, J. I., Crawford, S., Ireland, M., Lomberg, B., Mamajek, E. E., Mellon, S. N., & Talens, G. J. "Revisiting the pulsational characteristics of the exoplanet host star β Pictoris", Astronomy and Astrophysics, 627, A28 (2019) . https://doi.org/10.1051/0004-6361/201834744