A red / near-ir Spectrograph for GTC NEREA (Near Earths and high-res Exoplanet Atmospheres)

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1 A red / near-ir Spectrograph for GTC NEREA (Near Earths and high-res Exoplanet Atmospheres) Enric Palle, Guillem Anglada, Ignasi Ribas Instituto de Astrofísica de Canarias Queen Mary University of London IEEC-CSIC Madrid, 2018

2 Call for new instrumentation for GTC We propose an instrument concept based on a double science case for exoplanets - Exploration of the nearest stars to Earth - Characterization of atmospheres from Hot Jupiters to Super-earths This spectrograph should become a common user instrument for a variety of science cases.

3 The Landscape of Exoplanets today #Planets > #Stars Multiple systems common Specially for M stars Most common: Super-earths Even the closest star has a potentially habitable planet

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5 One in 1,000-10,000 photons cross the planetary atmosphere One in 100,000-1,000,000 photons cross the planetary atmosphere

6 Focus of searches: brightest and closest stars TESS PLATO

7 Atmospheric characterization via High-Res Spec (FOV, +AO)

8 Exoplanet Atmospheres with ELTs This science case involves two separate techniques: a) Transmission spectroscopy b) Direct detection of the planet s reflected light. The TRLs defined for instruments such as HIRES enable both simultaneously, but it must be distinguished here than only the former relies on the need of an AO system. Both cases involve high-resolution spectrographs (R>100,000) in the near-ir

9 An opportunity in the short term for GTC

10 NEREA CARMENES ELTs

11 CASE 1 The closest planets to Earth

12 CASE 1 The closest planets to Earth Even the closest star has a habitable planet (Anglada-Escude et al, 2016)

13 Exciting Imagination!! Proxima-b Trappist-1b, c, d, e, f, g..

14 LA MAYORIA tienen VARIOS planetas del tamaño de la Tierra. 70% de las estrellas de nuestra galaxia son tipo M 10% de la masa del Sol o menor

15 CASE 1 The closest planets to Earth CARMENES Instrument is contributing to this search with really exciting planet discoveries.. soon to be announced J Solid Spanish Imprint in this area of research But M stars are faint and we are limited by instrumentation capabilities (SNR) Very late M stars

16 Example nearest transiting system. We cannot retrieve the masses via RV

17 The SED of M-Type Stars near-ir efficiency peak If possible, you want to observe here! 17 classical visible light RV instruments

18 CASE 1 The closest planets to Earth Transiting neighbors will be detected by TESS Sector 1 alerts: (1 of 26) already gave us - A naked-eye star super-earth - Saturn planet around an M star extremely amenable for atmospheric characterization TESS will provide 70 Earth, 650 Super-earths, 1100 Neptunes and 100 Hot Jupiter planets - Half will be around M stars, too faint even for ESPRESSO@VLT to measure masses In late 2020 s will come PLATO, will need literally 100s nights in RV facilities capable of 20 cm/s precision

19 CASE 1 The closest planets to Earth But what about non-transiting planets? Planet searches are justified as 1.- The closest planets to us will probably not transit -Probability of transits of Earth - Sun 0.5% -Probability of transit of Earth M star 1-2% 2.- TESS will miss longer period planets (habitable zone) Big niche for discovery, similar to CARMENES, but accessing smaller and dimmer stars. Searches on 10-m telescopes are costly, so this would be a volume limited search.

20 CASE 2 Exoplanet Atmospheres

21 CASE 2 Exoplanet Atmospheres Chemical composition!!

22 High Resolution observation help us to get rid of the atmosphere: The planet moves at different speed than the star Snellen, 2010

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24 Thanks

25 CASE 2 Exoplanet Atmospheres MASCARA1 with HARPS-N Casasayas et al, 2018

26 The Landscape in 2025 Multi-resolution approach common + Low Resolution Ø Ø Ø Ø Composition Pressure levels Rayleigh slopes Clouds/hazes (Louie, 2017) High-resolution spectra

27 CASE 2 Exoplanet Atmospheres NEREA@GTC (or ESPRESSO-like@ GTC) won t reach Earth-like atmospheres or biomarkers, but will be unique tools to explore the present distribution and evolutionary history of small planets

28 Proposed Instrument Broad Spectral range nm Spectral Resolution R > 70,000 up to 110,000 Stability 1 m/s Compact design (behind AO system) Fast construction and development Common user instrument for a variety of science cases.

29 Highest resolution and relevant echelle spectrometer parameters Geometric optics limit, no diffractive effects D T = 10 m is fixed Commercially available gratings l tan θ = 4 l D s = 0.21 m For GTC,, seeing limited 1, this leads to R ~ Options to increase R l Change effective D s, but non-trivial optics needed (pupil slicer, ech. gratings mosaic) l Reduce input image size moderate performance AO

30 Two fiber feeds High resolution mode. Input image size : 0.3 arcsec l R ~ l Wavelength coverage microns l Moderate AO req. (17 x 0.7 µm, 7 x diff at 1.7 µm l D s = 0.2m, Ech. grat : 15.0 gr/mm, blaze angle 76 deg (R4). Similar tank as CARMENES. l Detector : 4k x 1k is enough Can accept efficiency modes if AO does not work (or underperforms) l Moderate, input size : 0.6, R ~ l Very high efficiency (no AO), input size : 1.0, R ~ l High-resolution mode also work with no AO, but has high loses. GTC proposal Top level design options for a highresolution spectrometer for a 10m telescope. Keep it as simple as possible. Take advantage of existing AO to attain high resolution. Must be still usable without AO. Features : no pupil or image slicer, single echelle grating, x-disp with prism or VPH D s D s is a crucial instrument parameter is the spectrometer beam diameter, as only standard sizes are easily manufactured (largest Richardson gratings is 21 cm) Single pass design also possible but D s = 15 cm, limiting resolution at , unless image size can be made smaller (e.g. 0.2 would preserve R= )

31 Summary We will be proposing a nm high-resolution spectrograph (R>70,000) for GTC Design is very preliminary (0) at the moment but will move forward in the coming months Purpose of the talk: We welcome input, institutional collaborations and enthusiastic colleagues to join

32 Thanks!!