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| Superimposed images of FH1 flight recorded in Finland. Photo Credit: Maria Gritsevich |
Apparently interstellar meteors may be the result of accelerated meteoroid collisions with massive objects passing near or through the Solar System. This was reported by Maria Gritsevich, Associate Professor at the University of Helsinki and Senior Researcher at the Ural Federal University, at the VII Workshop on Robotic Autonomous Observatories in Malaga, Spain.
The conclusion, announced by Maria Gritsevich at the workshop as co-author of a paper and scientific article published in the journal Icarus, is due to the study of meteor FH1. This is an astronomical event registered by the Finnish Fireball Network on October 23, 2022. The speed of FH1 exceeded the speed of objects within the solar system. Thus, FH1 could be both an object in the Oort Cloud, a theoretical spherical region - the source of long-period comets - at the edge of the Solar System, and an interstellar object.
"According to our hypothesis, the trajectory of the FH1 meteoroid could have been affected by the passage of the so-called Scholz star - a double star system - close to the Sun. This event is estimated to have occurred several tens of thousands of years ago, and the gravitational perturbations caused by it changed the orbit of the meteoroid", explains Maria Gritsevich.
The Science Forum in Málaga aims to demonstrate to the international research community the achievements of the last two years and the potential of BOOTES (Burst Observer and Optical Transient Exploring System), a global state-of-the-art network of autonomous robotic astronomical observatories located in the northern and southern hemispheres - in Spain, South Africa, China, New Zealand, Mexico and Chile.
Maria Gritsevich joined the scientific organizing committee of the workshop and opened the program of scientific presentations. One of her talks was devoted to the use of the BOOTES network and other observatories in the study of cometary outbursts. Such outbursts, characteristic of comets with periodic orbits and parabolic trajectories, make it possible to observe these relatively small celestial bodies and obtain new data on their formation and evolution.
"In the report, I considered such factors of the physics of a cometary outburst as the structure of the comet's solid icy nucleus, the sublimation of volatiles - gas and dust - from its surface as it approaches the Sun. As a result, there is an increase in the gas pressure under the comet's surface, the processes of crystallization of water ice in the nucleus and the associated exponential increase in the temperature of the nucleus, the release of even more energy from the ice, the explosive expansion of superheated volatile gases and further increase in pressure, the subsequent destruction of relief layers on the comet's surface, various types of emissions - from local outgassing to the separation of large fragments, including fragments of the nucleus, and their crushing. The interval between eruptions in some comets can be of the order of centuries. At the same time, other comets, due to the peculiarities of their composition and thermal properties, may never experience outbursts or fragmentation", comments Maria Gritsevich.
To illustrate how cometary outbursts occur, Maria Gritsevich gave examples of several such events observed over the past two centuries. Giant eruptions were accompanied by the release of colossal amounts of dust, deformation of nuclei, a sharp increase in the brightness of comets, or their complete destruction. According to Gritsevich, the orbits of the huge amount of dust particles ejected in a comet outburst eventually converge in the so-called node, on the opposite side of the Sun, and then transfer to the second node, near the original site of the explosion. The result is an hourglass-shaped dust trail of the comet.
"Our model takes into account the effects of solar radiation pressure, gravitational perturbations caused by celestial bodies such as Venus, Earth, Moon, Mars, Jupiter and Saturn, and the gravitational interaction between dust particles and the parent comet," says Maria Gritsevich.
The authors of the model used it to explain data from more than 10 years of observations of the dust trail of Comet 17P/Holmes, obtained with several telescopes in Finland, Spain, and Slovakia. This comet has an orbital period of about seven years. In October 2007 it experienced a huge explosion and mass ejection, the largest in the documented history of comets. At the same time, the brightness of 17P/Holmes increased by nearly a million times and remained intense for an entire year. The results of the simulations allowed us to determine the location and behavior of the dust trail of Comet 17P/Holmes, including on the way to the outbreak point in 2007 and at the outbreak point itself. The experience gained will help to make efficient calculations for the next similar event. Observations of the dust trail of the 2007 outburst during last year and early this year have fully confirmed the validity of the modeling results.
Another object of research of the group of scientists with the participation of Maria Gritsevich - comet 12P with an orbital period of just over 70 years. The last flare of this comet was observed on July 20 this year. In July and August, Gritsevich and her colleagues obtained images of 12P using the BOOTES system. The observations made it possible to determine physical parameters of the dust environment, including the color of the dust and the volume of ejected particles.
Additional information: The BOOTES, the creation of which was completed in 2022, aims to bridge the knowledge gap about the Solar System and the Universe by continuously observing various astrophysical phenomena in real time and in a coordinated manner. By responding to signals from Earth-orbiting satellites that record specific cosmic phenomena, and by aggregating data from its own instruments, BOOTES will obtain crucial information about objects such as active galactic nuclei, active galactic disks, suspected neutrino sources and gravitational wave emitters, cosmic gamma-ray bursts, supernovae in distant galaxies, extrasolar planets, and nearby objects such as variable stars in our Galaxy, small planets, asteroids, meteoroids, and meteors.
Many of these objects have traditionally eluded comprehensive study because of their brief and fleeting appearances, elusive and unpredictable nature. To date, the BOOTES network has produced impressive scientific results that contribute to the study of long-lived gamma-ray bursts associated with the death of massive stars and to the refinement of models of such bursts.
In 2017, for example, the BOOTES facility in Mexico was the only astronomical station in the northern hemisphere to observe the event known as GW170817A. This is the first recorded gravitational wave burst resulting from the merger of two neutron stars.
This phenomenon enabled the world's first simultaneous study of light and gravitational waves. In 2021, BOOTES made a valuable contribution to pioneering research on the giant magnetic flare of a magnetar, a neutron star with the strongest magnetic fields in the Universe.
Thus, it can be argued that BOOTES has revolutionized astrophysical research and the understanding of the dynamic nature of the universe.
In addition, the BOOTES can also monitor space debris and scan the sky for objects that pose a potential threat to humanity.
The Workshop on Robotic Autonomous Observatories was held in Málaga for the seventh time, and for the first time since the coronavirus pandemic, ensuring the direct participation of the participants. The first such workshop was held 14 years ago.
Published in journal: Icarus
Source/Credit: Ural Federal University | Alexander Zadorozhny
Reference Number: sn110123_01
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