One of the featured guests of Puerto de Ideas Antofagasta, which began this Thursday and runs until Sunday, is Itziar de Gregorio, Spanish astronomer, head of the science office at the European Southern Observatory.
Gregorio will be at the talk this Saturday “The fascinating odyssey in the search for exoplanets”at 12:00 p.m. in the Eloísa Díaz room at Sitio Cero.
The existence of other worlds and the possibility of life on other planets continue to be one of the greatest mysteries in human history. Almost three decades ago, the first planet was discovered around a star other than our Sun. Since then, scientists from around the world have made a titanic effort to characterize the thousands of exoplanets detected so far. This advance has been possible thanks to the technological development of state-of-the-art telescopes, many of which are located in Chile.
This talk is a journey through other worlds to explore current scientific theories on planetary formation and possible environments that could support life. It will also address what the next generation of giant telescopes will offer, such as the Extremely Large Telescope (ELT) of the European Southern Observatory (ESO), and the modernization project of the Atacama Large Millimeter/submillimeter Array (ALMA) telescope, to get us ever closer to the answer about whether we are alone in the universe.
Itziar de Gregorio
Trajectory
De Gregorio has been head of the Science office of the European Southern Observatory (ESO) in Chile since 2018. Previously she was head of the ALMA observatory program management group. She did her PhD at Spain’s National Institute of Aerospace Technology, where she used NASA antennas to make observations in the field of radio astronomy and study star formation.
In 2006, she joined as an ESO ALMA Fellow with duties at the APEX telescope, the Atacama Test Site in Socorro, New Mexico, and the ALMA Operations Support Center near San Pedro de Atacama. In 2010, she became the first female astronomer in ALMA’s scientific operations group. Her main research activities focus on star and planetary formation.
As head of the ESO Science Office, her job has been to “promote a stimulating scientific environment so that ESO astronomers can perform cutting-edge science while supporting the construction and operations of the large ESO observatories.”
“The truth is that it has been quite a challenge and a great team effort. Every day I interact with experienced scientists and young astronomers who exude excellence, and that is very inspiring.”
She is in charge of ESO Chile’s science programs and the team of doctoral students and postdoctoral fellows (ESO fellows).
“From the science office we run the scientific visitor programs, international ESO conferences and also the scientific activities of the Organization in Chile. In addition, I lead the Faculty, made up of the most experienced team of scientists.”
ESO milestones
De Gregorio highlights that ESO has had several milestones. Observations made with ESO telescopes have enabled a great deal of progress, and over the years have been responsible for some fundamental discoveries in this science, he says.
For example, in the area of exoplanets It was possible to obtain for the first time the image of a planet outside the Solar System rotating around its star. This was using ESO’s VLT at the Paranal Observatory in 2004, which is located in the Antofagasta Region.
Other milestones are in the field of black holes. For a long time it was suspected that a black hole was hiding in the heart of the Milky Way, our galaxy, but it could not be proven. After more than 15 years of observations with multiple telescopes, including telescopes from ESO’s La Silla and Paranal observatories, it was possible to individually distinguish the stars in the center of the Milky Way, and even more so, their movement could be determined, which It was influenced by an immense gravitational field.
The conclusion was that this enormous force came from an immense supermassive black hole, which we cannot see, but which has a mass almost three million times greater than that of our Sun.
Another iconic investigation was achieved thanks to the international EHT collaboration, in which the ALMA and APEX radio telescopes participated, also located in the Antofagasta Region. The EHT unites telescopes from around the world to form a virtual Earth-sized telescope. Thanks to this virtual telescope, it was taken the first image of a black holea photograph that has become a kind of icon of contemporary astronomy.
“Regarding what we expect from ELT, I can tell you that when we built ALMA we knew the scientific specifications we had to achieve, but we were not prepared to see the transformative science it is achieving. We are eager to know what the discoveries will be and the new limits that the ELT will impose on us,” he comments.
The star of ESO
The star of ESO is undoubtedly the Extremely Large Telescope (ELT). But what is it like and what are its functions?
“Since 2005, ESO has been working to develop an extremely large optical/infrared telescope. After a long development, ESO is in the midst of construction of the Extremely Large Telescope, or ELT for its acronym in English,” explains the astronomer.
He adds that ESO’s ELT will have a main mirror measuring 39 meters in diameter and will be the largest visible and infrared light telescope in the world. In addition to its unprecedented size, he says, the ELT will have cutting-edge instruments, designed to study different scientific fields.
“These advances can lead to a paradigm shift in the way we perceive the universe, similar to what happened with Galileo’s telescope 400 years ago,” he emphasizes.
Along with this, the ELT “will address some of the biggest challenges of our time. With the ELT, Earth-like planets can be located around other stars and it could be the first telescope with which evidence of life outside our Solar System is found.”
“It will also be possible to investigate the farthest reaches of the cosmos, which will allow us to understand the properties of the oldest galaxies and the nature of dark energy and matter. What’s more, due to the capabilities of the ELT, the astronomical community is preparing for the unexpected, that is, discoveries that will open new fields and, of course, new questions about the cosmos.”
Other lands
There are currently several scientific theories about planetary formation and possible environments that could support life.
“Planets form within disks of gas and dust around young stars, also called protoplanetary disks. The most accepted theory on the formation of planets hypothesizes that tiny grains of dust from this disk collide, becoming stuck together and begin to grow, forming small rocks with enough mass to continue gravitationally attracting more solids, until forming the solid core of a planet. planet. If they are massive enough, large amounts of gas can be attracted, forming gas giants,” he explains.
However, “this theory is not perfect and requires too long times to form giant planets, there is another theory that can explain the formation of this type of planets in shorter times. This is the theory of gravitational instabilities, where a sufficiently massive protoplanetary disk can fragment into small nuclei that collapse and quickly form a giant planet. However, this theory cannot explain the abundance of heavy elements on gas giant planets.”
To form planets like Earth, “and of course, life as we know it, the presence of liquid water as a solvent is needed. “In planetary systems there are two fundamental environments where water is found in a liquid state.”
“One is the habitable zones, regions neither too close nor too far from the star of the planetary system, so that the water does not evaporate or freeze. The second zone would be the moons around gas giant planets with frozen oceans on the surface and liquid water in the deeper layers.”
In the Solar System, that means the area where Earth and Mars are, and the icy moons around Jupiter and Saturn, such as Europa, Ganymede, Callisto or Enceladus.
planetary fauna
When asked about which are the “main” exoplanets discovered so far, and why, the astronomer reveals that scientists have discovered “a quite interesting planetary fauna, with some planets similar to those we find in our solar system and others very different.” ”.
“About two-thirds of the exoplanets detected belong to Neptune-like planets, called mini-Neptunes and super-Earths. “Super-Earths are rocky planets up to twice the mass of Earth, and mini-Neptunes, as their name suggests, are planets smaller than Neptune, but with large atmospheres.”
In addition, there is a group of gas giant planets so close to their star that their atmosphere continually evaporates, and other moon-like ocean worlds around Jupiter and Saturn, he says.
“With these very different worlds it seems that our Solar System is unusual. However, planet detection is biased by our limited observation techniques. In the future, with new telescopes like the ELT, we hope to complete the statistics of exoplanets by studying the population of terrestrial-type planets or even lower mass ones.”
The techniques
Although they cannot photograph them directly, scientists have developed various techniques to detect and describe them.
“We have several techniques for detecting planets, with the transit technique being the most popular method and the one that provides us with the most information. It consists of studying the decrease in the brightness of a star caused by the passage of a planet in front of the star,” explains De Gregorio.
“Our telescopes can capture this decrease in brightness and obtain information about the planet. Furthermore, if the planet has an atmosphere, the light from the star will be absorbed by the compounds present in the atmosphere, leaving its mark which can indicate the presence of certain gases such as water vapor.”
As for life, “we can determine life by studying the presence of biomarkers in its atmosphere.”
“Biological beings have the capacity to emit large amounts of gas into the atmosphere of the planet they inhabit. For example, on Earth our atmosphere has oxygen produced by plants and large amounts of methane produced mainly by the decomposition of living beings. If we find exoplanets with the presence of water, carbon dioxide, oxygen and methane, as occurs on Earth, and they are also in an area where water could be in a liquid state, the probability of life existing on that planet would be high. ”.
The next generation of giant telescopes will be key for them.
“They will be so-called extremely large telescopes, such as ESO’s ELT, whose primary mirror will be 39 m in diameter. The objective of building the next generation of giant telescopes is to take a qualitative step in understanding the Universe,” comments the astronomer.
“This type of telescope will impact practically all areas of Astronomy, as it will study very faint celestial objects with an unprecedented level of detail. In the area of planetary sciences, ESO’s ELT will make possible the detection and characterization of Earth-like planets, as well as the chemical composition of their atmosphere. Thus the detection of the first terrestrial-type exoplanet with biological activity is likely to occur from Chile, thanks to this European giant,” he concludes.