Nicolas Lodieu, Javier Licandro Goldaracena, Diego Hidalgo Soto, Pilar Montañés Rodríguez, Antonio L. Cabrera Lavers, Grzegorz Nowak, Nicolas Crouzet, Felipe Murgas Alcaino, Nuria Casasayas Barris, Guo Chen, David López Fernández-Nespral, Patricia Chinchilla Gallego, Víctor J. Sánchez Béjar, Juan Antonio Belmonte Avilés, Jorge Prieto Arranz, Lisa Nortmann, Roi Alonso Sobrino, Hans J. Deeg
Colaboradores del IAC: Zenghua Zhang, Bartosz Gauza, Pablo Rodríguez Gil
Paulo Miles Paez (Univ. Western Ontario); Maria Rosa Zapatero Osorio, M. Mas-Hesse (CAB-INTA-CSIC, Spain); M. Deleuil (LAM Marseille); D. Gandolfi, (Univ. Torino); M. Fridlund (Leiden and Onsala); L. Doyle (SETI); H. Rauer, J. Cabrera, Sz. Csizmadia (DLR); D. Pollacco (Queens Univ. Belfast); E. Günther, A. Hatzes (Tautenburg Obs); T. Mazeh (Tel Aviv Univ.); T. Boyajian (Yale); B. Tingley (Aarhus U.); P. Klagyivik (Konkoly)
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. In addition to this, the end of the CoRoT mission and the modifications to the Kepler mission (problems in their reaction wheels), it is expected that the focus will change from exoplanet detection to their characterization. In this context, and due to the distant launching dates of upcoming related satellites (i.e. JWST, CHEOPS, TESS, Echo or DISH), an opportunity of several years is expected, in which ground-based instruments will dominate the exoplanets field.
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 Co-Is.
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, W -FC, EChO, 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 (HARPS-N, HORUS, LCOGT, SONG, CARMENES).
- Lack of color changes in the transits of disintegrating material close to a white dwarf
During the last decades, growing evidence about the presence of planetary material around white dwarfs has been established. The features of heavy elements in the spectra of a large fraction (25-50%) of these objects needs a frequent accretion of material orbiting close to the white dwarf. Additionally, at least 4% of these objects are known to host dusty disks. The space mission K2, that re-uses the Kepler instrument after a failure of two of its four gyroscopes, recently detected transiting material around WD1145+017, with periods in the 4.5-5h range, and a depth variability with scales of a few days. This is attributed to the presence of disintegrating planetesimals, due to the high temperatures close to the white dwarf. The K2 data suffer from a poor sampling to study this object (30 min), and they lack chromatic information. In this work, we used the IAC80 telescope to predict deep transits that were observed a few hours later with OSIRIS at GTC. The close to 1-min sampling, and the information in four visible bands, allowed for the first detection, with an unprecedented precision, of the color of the transiting material. The lack of depth changes in the different bands (gray transits) served to set constraints to the minimal particle sizes of the transiting material, which have to be 0.5 microns or larger for the most common minerals.
- Earth’s albedo variations 1998-2014 as measured from ground-based earthshine observations
The Earth’s albedo is a fundamental climate parameter for understanding the radiation budget of the atmosphere. It has been traditionally measured from space platforms, but also from the ground for sixteen years from Big Bear Solar Observatory by observing the Moon. The photometric ratio of the dark (earthshine) to the bright (moonshine) sides of the Moon is used to determine nightly anomalies in the terrestrial albedo, with the aim is of quantifying sustained monthly, annual and/or decadal changes. We find two modest decadal scale cycles in the albedo, but with no significant net change over the sixteen years of accumulated data. Within the evolution of the two cycles, we find periods of sustained annual increases, followed by comparable sustained decreases in albedo. The evolution of the earthshine albedo is in remarkable agreement with that from the CERES instruments, although each method measures different slices of the Earth’s Bond albedo.
During 2016 has begun the main program of CARMENES dedicated to the search for rocky planets around 300 M stars by the radial velocity method. Up to date, more than 4000 optical and near-infrared spectra of more than 240 stars has been obtained.
Discovery of an isolated planet of L4-L6 spectral type in the Upper Scorpius star forming region (Peña-Ramírez et al. 2016). It is one of the coolest and less massive isolated planetary-mass objects currently known.