Three ring structures in the planet-forming region of the circumstellar disk where metals and minerals act as a reservoir for planetary building blocks.
A research team including astronomers from the Max Planck Institute for Astronomy (MPIA) discovered three ring structures in planetary nurseries in the inner planet-forming disks of young stars. This configuration suggests two things. Jupiter-Massive planets are forming in the gaps between the rings. Detailed analysis is consistent with abundant solid iron particles complementing the dust composition. As a result, this disk is thought to contain metals and minerals similar to those found on terrestrial planets in our solar system. This provides a glimpse of conditions similar to the early Solar System more than 4 billion years ago, during the formation of rocky planets such as Mercury. Venusand the earth.
Three iron rings in a planet-forming disk
The origins of the Earth and the solar system inspire scientists and the general public alike. By studying the current conditions of our home planet and other celestial bodies in our solar system, researchers have discovered that they evolved from the disk of dust and gas that surrounded the sun around 4.5 billion years ago. The detailed situation at the time was clarified.
Three rings suggesting two planets
Remarkable progress has been made in the study of star and planet formation in distant celestial bodies, and it is now possible to investigate the conditions of the environment around young stars and compare them with the environment obtained in the early solar system. . European Southern Observatory (ESO) very large telescope Interferometry (VLTI), an international team of researchers led by József Varga of the Konkoli Observatory in Budapest, Hungary, has done just that. They observed the planet-forming disk of the young star HD 144432, about 500 light-years away.
“When we studied the distribution of dust in the innermost region of the disk, we discovered for the first time a complex structure in which dust is piled up in three concentric circles in such an environment,” says Roy van Boekel. He is a scientist at the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, and co-author of a basic research paper published in the same journal. astronomy and astrophysics. “That region corresponds to the zone in our solar system where rocky planets formed,” van Boekel added. Compared to our solar system, the first ring around HD 144432 is within Mercury’s orbit, and the second ring is near Mercury’s orbit. Marstrajectory. Moreover, the third ring roughly corresponds to Jupiter’s orbit.
Until now, astronomers have mainly discovered such formations on larger scales, corresponding to regions beyond Earth. Saturn revolves around the sun. Ring systems in disks around young stars typically indicate that planets form within the gaps as the planets accumulate dust and gas along the way. However, HD 144432 is the first example of such a complex ring system so close to its host star. It occurs in zones rich in dust, the building blocks of rocky planets like Earth. Assuming that the rings indicate the presence of two planets forming within the gap, the astronomers estimated their masses to be roughly similar to that of Jupiter.
The situation may be similar to the early solar system
The astronomers determined the composition of the dust throughout the disk to a distance from the central star equivalent to the distance of Jupiter from the Sun. What they discovered is familiar to scientists who study Earth and the rocky planets of the solar system, including the various silicates (compounds of metals, silicon, and oxygen) that exist in the Earth’s crust and mantle. ), other minerals, and possibly metallic iron, which exists on Mercury and Earth. core. If confirmed, this study would be the first to discover iron in a planet-forming disk.
“Astronomers have previously described observations of dusty disks of a mixture of carbon and silicate dust, a material found almost everywhere in the universe,” van Boekel said. However, from a chemical point of view, a mixture of iron and silicates is more likely in the hot inner region of the disk. And indeed, the chemical model that Varga, lead author of the underlying research paper, applied to the data produced better results when iron was introduced instead of carbon.
Furthermore, the dust observed on the HD 144432 disk can reach temperatures as high as 1800 Kelvin (about 1500 degrees Celsius). Celsius) The temperature is higher at the inner edge, around 300 Kelvin (approximately 25 degrees Celsius) further out. Minerals and iron melt and recondense in hot regions near the star, often forming crystals. Second, carbon particles cannot withstand heat and exist as carbon monoxide or carbon dioxide gas. However, carbon may still be an important component of the solid particles in the cold outer disk, which cannot be traced in the observations made for this study.
Iron-rich, carbon-poor dust would also be well suited to solar system conditions. Mercury and Earth are iron-rich planets, but Earth contains relatively little carbon. “We think the HD 144432 disk could be very similar to the early solar system, which provided large amounts of iron to the rocky planets we know today,” van Boekel said. “Our study may provide another example of how the composition of the solar system can be very typical.”
Interferometer resolves details
Obtaining results was only possible if the very high resolution observations provided by VLTI were required. By combining his four VLT 8.2 meter telescopes at ESO’s Paranal Observatory, astronomers can resolve details as if they were using a telescope with a 200 meter diameter primary mirror. Varga, van Boekel, and their collaborators used three instruments to acquire the data, covering a wide range of wavelengths from 1.6 to 13 micrometers, which represents infrared light.
MPIA provided key technical elements for two devices: GRAVITY and Multi AperTure Mid-Infrared SpectroScopic Experiment (MATISSE). One of MATISSE’s main objectives is to investigate rocky planet-forming zones in disks around young stars. “By studying the interior regions of protoplanetary disks around stars, we aim to discover the origins of the various minerals contained in the disks, the minerals that later formed the solid components of planets such as Earth.” said MPIA Director Thomas Henning. Co-PI of MATISSE equipment.
However, producing images using interferometers of the kind we are accustomed to obtaining from a single telescope is not easy and is very time-consuming. A more efficient way to use valuable observation time to decipher an object’s structure is to compare sparse data with models of potential target configurations. For HD 144432 disks, a three-ring structure best represents the data.
How common are structured iron-rich planet-forming disks?
Besides our solar system, HD 144432 appears to provide another example of planets forming in an iron-rich environment. But astronomers don’t stop there. “There are still several promising candidates waiting for VLTI to consider in detail,” points out Van Boekel. In previous observations, the researchers found a number of disks around young stars, a configuration worth reconsidering. However, he plans to use his latest VLTI instruments to reveal its detailed structure and chemistry. Ultimately, astronomers may be able to determine whether planets commonly form in dusty, iron-rich disks near their parent stars.
Reference: “Mid-infrared evidence for iron-rich dust in the polycyclic inner disk of HD 144432” J. Varga, LBFM Waters, M. Hogerheijde, R. van Boekel, A. Matter, B. Lopez, K. Perrault , L. Chen, D. Nadella, S. Wolf, C. Dominique, Á. Kospal, P. Abram, J.-C. Augereau, P. Bouley, G. Bourdalot, A. Caratti-o-Garatti, F. Cruz-Sáenz de Miera, WC Duntsch, V. Gamez Rosas, Th. Henning, K.-H. Hofmann, M. Houllé, JW Isbell, W. Jaffe, T. Juhász, V. Kecskeméthy, J. Kobus. , E. Kokoulina, L. Labadie, F. Lycou, F. Millour, A. Moór, N. Morujão, E. Pantin, D. Schertl, M. Scheuck, L. van Haastere, G. Weigelt, J. Woillez, P. Woitke, January 8, 2024. astronomy and astrophysics.
DOI: 10.1051/0004-6361/202347535
The MPIA researchers who participated in this study are Roy van Boekel, Marten Scheuck, Thomas Henning, Jacob W. Isbell, and Ágnes Kóspál (also at the HUN-REN Astronomy and Geosciences Research Center at Konkoli Observatory, Budapest, Hungary). [Konkoly]; CSFK, MTA Center of Excellence, Budapest, Hungary [CSFK]; ELTE Eötvös Lorand University, Budapest, Hungary [ELTE]), Alessio Caratti o Garatti (also INAF-Osservatorio Astronomico di Capodimonte, Naples, Italy).
Other contributors are: J. Varga (Konkoly, CSFK, Leiden Observatory, Netherlands) [Leiden]), LBFM Waters (Radboud University, Nijmegen, The Netherlands; SRON, Leiden, The Netherlands), M. Hogerheijde (Leiden, University of Amsterdam, The Netherlands). [UVA]), A. Matter (Côte d’Azur Observatory/CNRS, Nice, France) [OCA]), B. López (OCA), K. Perrault (University Grenoble Alpes/CNRS/IPAG, France) [IPAG]), L. Chen (Konkoly; CSFK), D. Nadella (Leiden), S. Wolf (University of Kiel, Germany). [UK]), C. Dominique (UVA), P. Abraham (Konkoly; CSFK; ELTE), J.-C. Augereau (IPAG), P. Boley (OCA), G. Bourdarot (Max Planck Institute for Extraterrestrial Physics, Garching, Germany), F. Cruz-Saenz de Miera (Konkoly, CSFK, University of Toulouse, France), WC Danchi (NASA Goddard Space Flight Center, Greenbelt, USA), V. Gamez Rosas (Leiden), K.-H. Hoffmann (Max Planck Institute for Radio Astronomy, Bonn, Germany) [MPIfR]), M. Houllé (OCA), W. Jaffe (Leiden), T. Juhász (Konkoly, CSFK, ELTE), V. Kecskeméthy (ELTE), J. Kobus (United Kingdom), E. Kokoulina (University of Liège, Belgium). ; OCA), L. Labadie (University of Cologne, Germany), F. Lykou (Konkoly; CSFK), F. Millour (OCA), A. Moór (Konkoly; CSFK), N. Morujão (University of Lisbon and Universidade do Porto, Portugal), E. Pantin (AIM, CEA/CNRS, France, Gif-sur-Yvette), D. Chertle (MPIfR), L. Van Haastert (Leiden), G. Weigert (MPIfR), J. Voyles (Europe) Southern Observatory, Garching, Germany), P. Wojtke (Austrian Academy of Sciences Institute for Space Studies, Graz, Austria), collaboration between MATISSE and GRAVITY