Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 09.02.2024. Speaker: Sylvestre Lacour (Paris Observatory/LESIA) Title: The ExoGRAVITY project - observations of exoplanets from the ground with optical interferometry Abstract: I will talk about the latest observations and results with the GRAVITY instrument installed at the VLTI, Paranal observatory.

1. The ExoGRAVITY TEAM:
R. Abuter, A. Amorim, R. Asensio-Torres, W. Balmer, M. Baubock, M. Benisty, J.P. Berger, H. Beust, A. Boccaletti, M. Bonnefoy, H. Bonnet, G. Bourdarot,
W. Brandner, F. Cantalloube, B. Charnay, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé du Foresto, A. Cridland, P.T. de Zeeuw, R. Dembet, J. Dexter ,
A. Drescher, G. Duvert, A. Eckart, F. Eisenhauer, F. Gao, P. Garcia, R. Garcia Lopez, T. Gardner, E. Gendron, R. Genzel, S. Gillessen, C. Ginsky, J. Girard,
A. Greenbaum, X. Haubois, G. Heissel, T. Henning, S. Hinkley , S. Hippler, M. Horrobin, M. Houllé, Z. Hubert, A. Jiménez-Rosales, L. Jocou, J. Kammerer,
P. Kervella, M. Keppler, L. Kreidberg, M. Kulikauskas, S. Lacour, A.-M. Lagrange, L. Lasi , V. Lapeyrère, J.-B. Le Bouquin, P. Léna, A. Mérand, A.-L. Maire,
P. Mollière, J. Monnier, M. Nowak, D. Mouillet, A. Muller, E. Nasedkin, T. Ott, G. Otten, D. Oré , T. Paumard, C. Paladini, K. Perraut, G. Perrin, L. Pueyo,
O. Pfuhl, J. Rameau, L. Rodet, G. Rodriguez-Coira, G. Rousset, P. Rubini, S. Scheithauer, J. Shangguan, J. Stadler, O. Straub, C. Straubmeier, T. Stolker,
E. Sturm, L.J. Tacconi, E.F. van Dishoeck, A. Vigan, F. Vincent, S.D. von Fellenberg, J. Wang, K. Ward-Duong , F. Widmann, E. Wieprecht, E. Wiezorrek, J.
Woillez, and The GRAVITY Collaboration
…

2. 20/11/14 ExoGRAVITY 2

3. 20/02/2024 PLANETES project -- S. Lacour 3

4. 20/02/2024 4
PLANETES project -- S. Lacour

5. 20/11/14 ExoGRAVITY 5
SPHERE observation of Beta pictoris b (Lagrange et al. 2020)

6. 20/11/14 ExoGRAVITY 6

7. Single mode
fiber on planet
Single mode
fiber on star
20/11/14
Interferometer 1
Interferometer 2
Star
Planet
Telescope 1
Telescope 2
Single mode
fiber on planet
Single mode
fiber on star
δ OPD
Metrology
Laser
Metrology
Receivers
Star
Planet
7
PLANETES project -- S. Lacour

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ExoGRAVITY

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10. PDS70, 110pc, 8Myr, 2 planets
(Image SPHERE, Müller et al. 2018)
I/ Astrometry gives dynamical
masses
95% upper limit
for mass of b
Wang et al. (2021)
II/ Spectrum gives temperature and dust extinction
Teff = ~1300 K
Teff = ~1100 K
III/ Visibilities constrain the size of the circum-planetary disk
PDS 70 planets
20/11/14 ExoGRAVITY 10

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ExoGRAVITY

12. Mass c (10Mjup)
Nowak et al. 2021
Lagrange et al. 2021
Lacour et al. 2021
Beta Pictoris planets
20/11/14 ExoGRAVITY 12

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ExoGRAVITY

14. HD206893c is burning Deuterium !
Harps: radial velocity ==> detection + mass Gaia: absolute astrometry ==> mass
GRAVITY: spectrum ==> luminosity. The star is too bright!
Kammerer et al. 2021
Hinkley et al. 2023
20/11/14 ExoGRAVITY 14

15. 20/11/14 15
ExoGRAVITY
HR8799 planets

16. HR8799 planets
20/11/14 ExoGRAVITY 16
HR8799 planets (E. Nasedkin et al., submitted)
GRAVITY data

17. HR8799 planets
20/11/14 ExoGRAVITY 17

18. HR8799 planets
20/11/14 ExoGRAVITY 18

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20. 20/02/2024
PLANETES project -- S. Lacour
Help to proposals
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Training at telescope Atmosphere modeling
Workshops on
interferometry
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