Exoplanets and Astrobiology

    General
    Description

    The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable information about its physical properties, but also allowing to constrain the properties of the Solar system's planets within a more global context. The field is approaching to the important discovery of the first potentially habitable planets and encouraging more detailed studies of them. With the launching of upcoming related satellites like JWST, CHEOPS, TESS, ARIEL and PLATO, the exoplanets field faces a bright future.

    It is for this reason that this field is aid of, and at the same time promotes, the development of increasingly sensitive and stable instrumentation for both, ground-based telescopes and space missions. Our group is particularly prepared for these two fronts. On the one hand, during the last years we have developed observational and reduction techniques of exoplanet transits data for the ORM telescopes, ours being one of the most productive groups in the exploitation of GTC. On the other hand, all ESA space missions (present and future) related to exoplanets have one or more components of the project as CoIs. Within the frame of this project, we intend that IAC researchers maintain an advantageous position regarding the operation of OSIRIS and CanariCam, first light

    GTC's instruments, and participate in the construction, commissioning and operation of new instruments such as the high resolution optical spectrograph HORUS at GTC. The exploitation of the photometry and spectroscopy of transits with LIRIS at WHT is also one of our principal interests, especially in preparation for the installation in 2015 of EMIR on the GTC .

    To summarize, the project "Exoplanets and Astrobiology" will focus on these four action lines:

    1) The characterization of atmospheric and physical properties of exoplanets (GTC, WHT, ARIEL, HARPSN, CARMENES, ESPRESSO, etc. ..)

    2) The search and confirmation of exoplanets by transits techniques (CoRoT, Kepler, K2, CHEOPS, XO, LCOGT, W FC, DISH, etc. ..)

    3) The search and confirmation of exoplanet by radial velocity techniques (HARPSN, HORUS, LCOGT, SONG, CARMENES)

    4) Astrobiology

    Principal investigator
    Project staff
    1. Detection of He in the atmosphere of an exoplanet from the ground, published in Science
    2. Detection of a super-earth around Barnard star, published in Nature
    3. Detection of the first TESS planets, with several papers of high relevance
    4. Discovery of Na and Halpha features in the spectrum of KELT-20b with TNG
    5. Publication of the Handbook of Exoplanets, the most extensive work of reference in the field of exoplanets. The Handbook was edited by members of our group, and includes contributions by about 300 experts worldwide, including 12 members of IAC.

    Related publications

    • RoadRunner: a fast and flexible exoplanet transit model
      I present RoadRunner, a fast exoplanet transit model that can use any radially symmetric function to model stellar limb darkening (LD) while still being faster to evaluate than the analytical transit model for quadratic LD by Mandel & Agol. CPU and GPU implementations of the model are available in the PYTRANSIT transit modelling package, and come
      Parviainen, H.

      Advertised on:

      9
      2020
      Citations
      6
    • A giant planet candidate transiting a white dwarf
      Astronomers have discovered thousands of planets outside the Solar System 1, most of which orbit stars that will eventually evolve into red giants and then into white dwarfs. During the red giant phase, any close-orbiting planets will be engulfed by the star 2, but more distant planets can survive this phase and remain in orbit around the white
      Vanderburg, Andrew et al.

      Advertised on:

      9
      2020
      Citations
      138
    • Detection of Na in WASP-21b's lower and upper atmosphere
      Optical transmission spectroscopy provides crucial constraints on the reference pressure levels and scattering properties for the atmospheres of hot Jupiters. For certain planets, where alkali atoms are detected in the atmosphere, their line profiles could serve as a good probe to link upper and lower atmospheric layers. The planet WASP-21b is a
      Chen, G. et al.

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      10
      2020
      Citations
      18
    • Obliquity measurement and atmospheric characterisation of the WASP-74 planetary system
      We present new transit observations of the hot Jupiter WASP-74 b (T eq ~ 1860 K) using the high-resolution spectrograph HARPS-N and the multi-colour simultaneous imager MuSCAT2. We refined the orbital properties of the planet and its host star and measured its obliquity for the first time. The measured sky-projected angle between the stellar spin
      Luque, R. et al.

      Advertised on:

      10
      2020
      Citations
      16
    • The CARMENES search for exoplanets around M dwarfs. A deep learning approach to determine fundamental parameters of target stars
      Existing and upcoming instrumentation is collecting large amounts of astrophysical data, which require efficient and fast analysis techniques. We present a deep neural network architecture to analyze high-resolution stellar spectra and predict stellar parameters such as effective temperature, surface gravity, metallicity, and rotational velocity
      Passegger, V. M. et al.

      Advertised on:

      10
      2020
      Citations
      24
    • Simulations Predicting the Ability of Multi-color Simultaneous Photometry to Distinguish TESS Candidate Exoplanets from False Positives
      The Transiting Exoplanet Survey Satellite (TESS) is currently concluding its 2 yr primary science mission searching 85% of the sky for transiting exoplanets. TESS has already discovered well over one thousand TESS objects of interest (TOIs), but these candidate exoplanets must be distinguished from astrophysical false positives using other
      Louie, Dana R. et al.

      Advertised on:

      8
      2020
      Citations
      1
    • The TOI-763 system: sub-Neptunes orbiting a Sun-like star
      We report the discovery of a planetary system orbiting TOI-763(aka CD-39 7945), a V = 10.2, high proper motion G-type dwarf star that was photometrically monitored by the TESS space mission in Sector 10. We obtain and model the stellar spectrum and find an object slightly smaller than the Sun, and somewhat older, but with a similar metallicity. Two
      Fridlund, M. et al.

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      8
      2020
      Citations
      17
    • A precise architecture characterization of the π Mensae planetary system★
      Context. The bright star π Men was chosen as the first target for a radial velocity follow-up to test the performance of ESPRESSO, the new high-resolution spectrograph at the European Southern Observatory's Very Large Telescope. The star hosts a multi-planet system (a transiting 4 M ⊕ planet at ~0.07 au and a sub-stellar companion on a ~2100-day
      Damasso, M. et al.

      Advertised on:

      10
      2020
      Citations
      49
    • π Earth: A 3.14 day Earth-sized Planet from K2's Kitchen Served Warm by the SPECULOOS Team
      We report on the discovery of a transiting Earth-sized (0.95R ⊕) planet around an M3.5 dwarf star at 57 pc, EPIC 249631677. The planet has a period of ∼3.14 days, i.e., ∼π, with an installation of 7.45 S ⊕. The detection was made using publicly available data from K2's Campaign 15. We observed three additional transits with SPECULOOS Southern and
      Niraula, Prajwal et al.

      Advertised on:

      10
      2020
      Citations
      8
    • Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS). IV. A spectral inventory of atoms and molecules in the high-resolution transmission spectrum of WASP-121 b
      Context. WASP-121 b is a hot Jupiter that was recently found to possess rich emission (day side) and transmission (limb) spectra, suggestive of the presence of a multitude of chemical species in the atmosphere. Aims: We survey the transmission spectrum of WASP-121 b for line-absorption by metals and molecules at high spectral resolution and
      Hoeijmakers, H. J. et al.

      Advertised on:

      9
      2020
      Citations
      117
    • Two close binaries across the hydrogen-burning limit in the Praesepe open cluster
      We present Keck I/OSIRIS and Keck II/NIRC2 adaptive optics imaging of two member candidates of the Praesepe stellar cluster (d = 186.18 ± 0.11 pc; 590-790 Myr), UGCS J08451066+2148171 (L1.5 ± 0.5) and UGCS J08301935+2003293 (no spectroscopic classification). We resolved UGCS J08451066+2148171 into a binary system in the near-infrared, with a K-band
      Lodieu, N. et al.

      Advertised on:

      8
      2020
      Citations
      0
    • The GTC exoplanet transit spectroscopy survey. XI. Possible detection of Rayleigh scattering in the atmosphere of the Saturn-mass planet WASP-69b
      Context. One of the main atmospheric features in exoplanet atmospheres, detectable both from ground- and space-based facilities, is Rayleigh scattering. In hydrogen-dominated planetary atmospheres, Rayleigh scattering causes the measured planetary radius to increase toward blue wavelengths in the optical range. Aims: We aim to detect and improve
      Murgas, F. et al.

      Advertised on:

      9
      2020
      Citations
      21
    • The CARMENES search for exoplanets around M dwarfs. Convective shift and starspot constraints from chromatic radial velocities
      Context. Variability caused by stellar activity represents a challenge to the discovery and characterization of terrestrial exoplanets and complicates the interpretation of atmospheric planetary signals. Aims: We aim to use a detailed modeling tool to reproduce the effect of active regions on radial velocity measurements, which aids the
      Baroch, D. et al.

      Advertised on:

      9
      2020
      Citations
      32
    • Characterization of the K2-38 planetary system. Unraveling one of the densest planets known to date
      Context. An accurate characterization of the known exoplanet population is key to understanding the origin and evolution of planetary systems. Determining true planetary masses through the radial velocity (RV) method is expected to experience a great improvement thanks to the availability of ultra-stable echelle spectrographs. Aims: We took
      Toledo-Padrón, B. et al.

      Advertised on:

      9
      2020
      Citations
      24
    • Atmospheric characterization of the ultra-hot Jupiter MASCARA-2b/KELT-20b. Detection of Ca II, Fe II, Na I, and the Balmer series of H (Hα, Hβ, and Hγ) with high-dispersion transit spectroscopy (Corrigendum)
      Casasayas-Barris, N. et al.

      Advertised on:

      8
      2020
      Citations
      4
    • K2-280 b - a low density warm sub-Saturn around a mildly evolved star
      We present an independent discovery and detailed characterization of K2-280 b, a transiting low density warm sub-Saturn in a 19.9-d moderately eccentric orbit (e = $0.35_{-0.04}^{+0.05}$ ) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280 b has
      Nowak, Grzegorz et al.

      Advertised on:

      7
      2020
      Citations
      4
    • The CARMENES search for exoplanets around M dwarfs. Variability of the He I line at 10 830 Å
      The He I infrared (IR) triplet at 10 830 Å is known as an activity indicator in solar-type stars and has become a primary diagnostic in exoplanetary transmission spectroscopy. He I IR lines are a tracer of the stellar extreme-ultraviolet irradiation from the transition region and corona. We study the variability of the He I triplet lines in a
      Fuhrmeister, B. et al.

      Advertised on:

      8
      2020
      Citations
      29
    • The CARMENES search for exoplanets around M dwarfs. Measuring precise radial velocities in the near infrared: The example of the super-Earth CD Cet b
      The high-resolution, dual channel, visible and near-infrared spectrograph CARMENES offers exciting opportunities for stellar and exoplanetary research on M dwarfs. In this work we address the challenge of reaching the highest radial velocity precision possible with a complex, actively cooled, cryogenic instrument, such as the near-infrared channel
      Bauer, F. F. et al.

      Advertised on:

      8
      2020
      Citations
      39
    • Limits on the Spin-Orbit Angle and Atmospheric Escape for the 22 Myr Old Planet AU Mic b
      We obtained spectra of the pre-main-sequence star AU Microscopii during a transit of its Neptune-sized planet to investigate its orbit and atmosphere. We used the high-dispersion near-infrared spectrograph InfraRed Doppler (IRD) on the Subaru telescope to detect the Doppler "shadow" from the planet and constrain the projected stellar obliquity
      Hirano, Teruyuki et al.

      Advertised on:

      8
      2020
      Citations
      61
    • HD 191939: Three Sub-Neptunes Transiting a Sun-like Star Only 54 pc Away
      We present the discovery of three sub-Neptune-sized planets transiting the nearby and bright Sun-like star HD 191939 (TIC 269701147, TOI 1339), a K s = 7.18 mag G8 V dwarf at a distance of only 54 pc. We validate the planetary nature of the transit signals by combining 5 months of data from the Transiting Exoplanet Survey Satellite with follow-up
      Badenas-Agusti, Mariona et al.

      Advertised on:

      9
      2020
      Citations
      16

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