IA/U.Porto Seminar - Red dwarfs, exoplanets and instrumentation at IAA-Granada - 25 janeiro 2017

In this contribution I will comment on the research and instrumentation lines we are currently carrying out in our group at the IAA. Among them, I will concentrate in two recent milestones in our work: the start of the CARMENES exoplanet survey and the discovery of Proxima b.

 

CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) is the next generation instrument built for the 3.5m telescope at the Centro Astronómico Hispano-Alemán (Calar Alto Observatory; CAHA, Almería, Spain), which is jointly operated by the Spanish National Research Council (CSIC) and the Max-Planck-Society (MPG). CARMENES has been built by a large international consortium of 11 institutes in Spain and Germany. It consists of two separate highly-stabilized, high-resolution echelle spectrographs covering both the visible, from 550 to 950 nm, and the near-IR, from 950 to 1700 nm, wavelength ranges with spectral resolution of R=82,000. They are fed by fibres from the Cassegrain focus of the telescope and were designed and built to achieve high-accuracy radial velocities (∼1 m/s) of nearby M-dwarf stars.

This talk overviews the main and unique design characteristics of CARMENES and, in particular, of its near infrared channel, whose manufacturing, integration and commissioning was led by the IAA. The channel MAIV phase was achieved in the last two years (2014-2015) and started commissioning on November 6th 2015. The commissioning phases, both technical and scientific, took six full weeks in the last two months of 2015. They have shown that the channel is well within requirements and performing to be able to achieve its objective, not proven before, of providing radial velocities precisions of 5 m/s, with a goal of 1 m/s. I will provide some insight on the strong aspects of its opto-mechanical and mechanical design and give some results of the performance of the channel at the telescope.

The Guaranteed Time Observations (GTO) programme has started on January 1st, 2016. Therefore, CARMENES is currently conducting a radial-velocity survey of 300 M dwarfs with a precision sufficient for detecting Earth-like planets in their habitable zones. It also is being offered in open time by the CAHA.

 

Also this year, in August, we have published clear evidence of a planet orbiting the nearest star to Earth, Proxima Centauri, at a distance of 1.295 parsecs (4.2 ly) and one of the best-studied low-mass star. The planet, named Proxima b, obits is cool M dwarf with a period of 11.2 days at a semi-major-axis distance of around 0.05 astronomical units. This distance puts the planet well within the temperate zone around its star, allowing a temperature suitable for liquid water to exist on its surface. The planet minimum mass is of 1.3 MEarth, a little more massive than the Earth and current knowledge points to a rocky composition. Proxima b is, therefore, the closest exoplanet to us, and it may also be the closest possible abode for life outside the Solar System.

In this presentation, I will explain our Pale Red Dot campaign (https://palereddot.org), resulting in the confirmation of Proxima b, in the context of our larger efforts to understand the formation and evolution of planetary systems around these cool stars, efforts materialised in the Cool Tiny Beats and CARMENES projects