I.Astro
PoET solar telescope, pointing at the Sun
A team from the Institute of Astrophysics and Space Sciences has successfully completed the installation of the first solar telescope at the Paranal Observatory.
Designed to support the search for exoplanets, it will study the Sun with unprecedented precision, helping to understand how stellar activity influences the detection of worlds beyond the Solar System.
After several weeks of work at ESO, in Chile, a team from the Institute of Astrophysics and Space Sciences made the first observations of the Sun with the PoET (Paranal solar ESPRESSO Telescope, or Espresso Solar Telescope in Paranal), on April 1st.
It is solar telescope made in Portugalinstalled in the middle of the Very Large Telescope (VLT), thus obtained its “first light” and will now operate in conjunction with the ESPRESSO instrumentone of the most accurate spectrographs in the world, to study the Sun in detail and improve exoplanet detection techniques.
“PoET has successfully completed its test observations, a process known as ‘first light‘, at the beginning of April, at the Paranal Observatory (ESO), located in the Atacama Desert, in Chile”, comments Nuno Cardoso SantosPrincipal Investigator of PoET and professor at the Faculty of Sciences of the University of Porto (FCUP).
“The first observations show that the system is working within specifications. Over the next few weeks, the team will be testing and optimizing the system before the start of the scientific campaign”, adds the researcher.
Both hardware and software of PoET were entirely developed by IA, in close collaboration between the teams at the Faculty of Sciences of the University of Lisbon (Ciências ULisboa) and the Astrophysics Center of the University of Porto (CAUP4)/FCUP.
ZAP // ESO; U. Porto; U.Lisbon
The PoET telescope (Paranal solar ESPRESSO Telescope), Nuno Cardoso Santos, Alexandre Cabral
Nuno Cardoso Santos, who is also leader of the IA Planetary Systems Team, clarifies that the Astrophysical ‘noise’ generated by the stars themselves hostesses “one of the biggest challenges in searching for other Earths.
“PoET observations could be fundamental in revealing and characterizing exoplanets that, at the moment, may be hidden in that noise”, details the researcher.
Most exoplanets are discovered analyzing subtle variations in light of the stars they orbit. However, just as the sunspots affect sunlightactivity on the surface of other stars distorts their spectra in a way that is registered as “noise” by current exoplanet detection instruments.
In this way, phenomena such as stains and magnetic activity can imitate or mask planetary signals.
Removing this “noise” from the spectra of distant stars It’s a challenge because it’s not yet fully understood how stellar activity changes the light we observe. To distinguish these effects, it is essential to rigorously understand how stellar activity changes spectra observed and for that there is no better laboratory than the Sun.
PoET was designed from scratch for this mission. The 60-centimeter-diameter main telescope observes specific regions of the Sun, such as individual sunspots, while a second, smaller telescope simultaneously collects light from the entire solar disk.
Once collected, the observation data is sent via a fiber optic cable of almost 75 meters, for analysis on the ESPRESSO high-resolution spectrograph.
“We will make it analyze very specific areas of the Sunwith a very high resolution, in a way that has never been done before”, says the co-Principal Investigator of PoET, Alexandre Cabral.
To the compare the spectrum of the solar disk with specific structures on its surface, it is possible to identify exactly how stellar activity changes the spectrum. This knowledge is then applied to the study of distant stars that may harbor exoplanets.
“Let’s use the Sun almost as a guinea pig to try to understand other stars”, highlights Alexandre Cabral, professor at Sciences ULisboa and responsible for the Instrumentation and Systems for Astronomy team at IA.
In order for these solar observations to be directly comparable with those of other stars, the team needed an extremely precise instrument. “ESPRESSO is the best instrument in its area, so the choice was obvious”, comments Nuno Cardoso Santos.
Installed on the VLT, during the night this spectrograph detects tiny variations in the movement of stars, which can be used to find or characterize planets in orbit. Now it is also being used during the day, with PoET, to analyze solar spectra.
“When alternating ESPRESSO between VLT at night and PoET during the daywe maximize the use of this instrument to help us find and characterize exoplanets”, comments Alain StopsVLT Operations Astronomer and ESO contact for the project.
“Thanks to the exceptional location of the Paranal Observatory, the number of days with suitable conditions for solar observations is expected to be very similar to that for night observations”, he adds.
Despite being physically located at the Paranal Observatory, PoET will be operated remotely from the University of Porto hub (UPorto) of IA, at CAUP. The solar data collected and analyzed by ESPRESSO will be made available to the scientific community through the ESO Science Archive.
To Earl BrinchmannESO Science Director and former IA Coordinator, “the successful deployment of PoET is reason for great satisfaction“.
“This project demonstrates the excellent quality of the astronomical community Portuguese language and how it can take advantage of ESO’s world-class excellence. It will have great scientific value and I look forward to seeing the results that will come from these observations”, he concludes.
