Twenty thousand observations made with the CARMENES instrument are published today. CARMENES is the "planet hunter" spectrograph of the 3.5-meter telescope at Calar Alto. CARMENES was co-developed by the Institute of Astrophysics of Andalusia (IAA-CSIC), and it has already discovered 59 planets, some of them lying in the habitable zone around red dwarf stars in the vicinity of the Sun.
The consortium of the CARMENES project has just published the data for about twenty thousand observations of a sample of 362 nearby, cool dwarf stars, taken between 2016 and 2020. The instrument, which operates at the 3.5-meter telescope of the Calar Alto Observatory, focuses on the search for Earth-like exoplanets (rocky and temperate), with the possibility of having liquid water on the surface if they are in the habitable zone around their star. Among the many data released now are those that have lead to the discovery of 59 exoplanets, a dozen being potentially habitable. The results are being published in the journal Astronomy & Astrophysics.
"Since it became operational, CARMENES has reanalyzed seventeen known exoplanets and has discovered and confirmed 59 new planets in the neighborhood of the Solar System, contributing significantly to expand the census of nearby exoplanets," says Ignasi Ribas, a researcher at the Institut de Ciències de l'Espai, (IEEC-CSIC) who leads the publication.
In fact, this instrument has boosted the number of known exoplanets around nearby cool stars. This first data release gives full open access to the international scientific community. This will increase the scientific production of CARMENES, which has observed almost half of all nearby dwarf stars (a part of them can only be observed from the southern hemisphere). In addition, the spectra obtained also provide valuable information about the stars’ photospheres and the atmospheres of their planets.
The paper published in Astronomy & Astrophysics is, precisely, the hundredth of the CARMENES consortium; this fact shows the success of the project. In this study, the data corresponding to the information obtained in visible light have been released. In the future, there will be a second release of data with the measurements in the (near-)infrared.
The CARMENES project continues through CARMENES Legacy-Plus. Co-led by the IAA-CSIC and by the ICE-CSIC, it is the natural continuation and extension of the successful observations with the instrument, which have accumulated almost eight hundred useful nights of observation over five years. LEGACY+ is intended as an exhaustive monitoring to detect and characterize their exoplanets for three hundred nights.
"In addition to the scientific project itself, from the IAA-CSIC and in close collaboration with the technicians and engineers of the Calar Alto Observatory, we are developing a technical improvement to enhance the accuracy of the infrared channel. Called CARMENES-PLUS, this instrumental project will maintain CARMENES as a highly competitive spectrograph, not only to expand the search for rocky planets but also to characterize their possible atmospheres, which constitutes the next observational challenge in the field – highlights Pedro J. Amado, the IAA-CSIC researcher who coordinated the development of the infrared arm of CARMENES and who also heads CARMENES-PLUS.
"The successful first stage of the CARMENES project, both of the original instrument and of the guaranteed time observations during its first five years of searching for other planets, concretized with the almost sixty new worlds discovered, shows the commitment of the entire Calar Alto team to long-term observational and instrumental projects. Commitment renewed to three other major legacy programs underway with the 3.5 m telescope. Two of these legacies (KOBE and LEGACY+) have already used the equivalent of a year of observation with CARMENES since 2021, to track down planets yet to be discovered and also to better understand those already known," concludes Jesús Aceituno, director of the Calar Alto observatory.
A UNIQUE INSTRUMENT
CARMENES uses the so-called technique of radial velocities, which looks for tiny oscillations in the movement of the stars due to the attraction of planets revolving around them. And it does so around red dwarf stars (or M dwarfs), smaller than our Sun, which offer in close orbits the conditions for the existence of liquid water and in which, unlike the solar-like stars, we can detect with current technology the oscillations (or ‘wobble’) produced by planets similar to ours.
CARMENES is a unique instrument in the world, both in terms of precision and stability, both qualities required to measure the small variations of speed that a planet produces on its star: CARMENES detects speed variations in the movement of stars located hundreds of thousand billions of kilometers away with an accuracy of the order of one meter per second. To do this, it works in vacuum conditions and with temperatures controlled to one thousandth of a degree.
CARMENES has been developed by a consortium of eleven German and Spanish institutions. In Spain, namely: the Institute of Astrophysics of Andalusia (IAA-CSIC), which co-leads the project and has developed the infrared channel; the Institut de Ciències de l'Espai, (IEEC-CSIC); the Complutense University of Madrid (UCM); the Institute of Astrophysics of the Canary Islands (IAC); and the Center for Astrobiology (CAB, CSIC-INTA). CARMENES has obtained funds from the Max Planck Society (MPG), the Spanish National Research Council (CSIC) and the members of the CARMENES consortium, with contributions from the Spanish Ministry of Economy and Finance (MINECO), the states of Baden-Württemberg and Lower Saxony, the German Science Foundation (DFG), the Klaus Tschira Foundation (KTS), the Junta de Andalucía and the European Union as well, through FEDER/ERF funds.
I. Ribas et al. “The CARMENES search for exoplanets around M dwarfs. Guaranteed-time observations data release 1 (2016-2020)” Astronomy & Astrophysics, February 2023
Instituto de Astrofísica de Andalucía
Calar Alto Observatory
Calar Alto Observatory is one of the infrastructures that belong to the national map of Unique Scientific and Technical Infrastructures (Spanish acronym: ICTS), approved on March 11th, 2022, by the Science, Technology and Innovation Policy Council (CPCTI)
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