#astronomical_observation

The Hubble telescope captured the galaxy NGC 685, made up of more than 100 million stars, appearing to orbit in the depths of space The average galaxy NGC 685 contains at least 100 million stars. About 58 million light-years from Earth, galaxy NGC 685 appears to be orbiting in the depths of space. The Hubble Space Telescope image, the last of six released as part of Hubble's Galaxy Week, shows the galaxy with its spiral arms dotted with countless pockets of bright blue regions called star clusters. Closer to the center of the galaxy, there are also many twisted red wisps, representing bands of gas and dust where new generations of stars form over eons. [caption id="attachment_69171" align="aligncenter" width="598"] galaxy[/caption] NGC 685: a galaxy home to millions of stars surprised Hubble NASA's accompanying description of the photo of the galaxy NGC 685 says it is located in the constellation Eridanus, measures about 60,000 light-years, and may contain at least 100 million stars. In comparison, the Milky Way is estimated to consist of approximately 100 billion stars. Despite the difference in size and number of stars, both galaxies have an interesting feature: they have a central bar that crosses the cores of the galaxies. In this image of the galaxy NGC 685, this red-flecked bar can be seen stretching horizontally within a small circle of gas and dust. Its intense brilliance is due to the many stars concentrated in a relatively small area. Previous studies have shown that such bars are observed in about two-thirds of spiral galaxies. Gas and other material flows into the galactic cores through these bridges, indicating that the galaxy's "formative period" is over, astronomers say. Although little time has been devoted to studying NGC 685, studying bar galaxies like this one helps astronomers understand how galaxies evolve and whether the process is different for our galaxy.

New research shows how comets could be the source of life on planets outside our solar system Scientists theorize that comets may have spread the organic ingredients necessary for the emergence of life on Earth. New research suggests that comets may also deliver these elements to exoplanets. During the formation of the solar system, the Earth was bombarded by asteroids, comets and other space objects. How the planet obtained the water and molecules necessary for life is still controversial, but comets are considered the most likely sources of these substances. [caption id="attachment_83089" align="aligncenter" width="650"] planet[/caption] But if comets could potentially bring the seeds of life to Earth, could they serve a similar function for exoplanets in other parts of the universe? To explore this question, a team of researchers from the Institute of Astronomy at the University of Cambridge developed mathematical models that helped reveal how comets could transfer similar vital elements to other planets in our galaxy. While the study's findings do not yet provide a definitive answer about the presence of life on other planets, they may help narrow the search for exoplanets that may support life. “wandering” from planet to planet, spread life throughout the Universe? “We continue to learn more about the atmospheres of exoplanets, so our goal was to find out whether there were planets where complex organic molecules could also be delivered by comets. It's possible that the molecules that enabled life on Earth were brought in by comets, and the same may be true for planets in other galaxies,” said Richard Enslow, one of the study's authors, who works at the Institute of Astronomy at the University of Cambridge. Over the past decades, scientists have learned more about the prebiotic molecules found in comets. For example, NASA's Stardust mission discovered samples of glycine, an amino acid and building block of proteins, in Comet Wild 2 (81P/Wild), and the European Space Agency's Rosetta mission discovered organic molecules in the coma of Comet Churyumov-Gerasimenko (67P). However, these organic molecules can be destroyed by strong comet impacts on the planet. So Enslow and his colleagues had to find scenarios in which a comet-planet collision occurs slowly enough to preserve the ingredients of life intact. The study, based on simulations, found that the slowest impact velocities occur in solar systems where planets are densely packed. Comets moving through such systems are slowed down by the gravitational influence of the planets. The simulations also showed that conditions for the emergence of life may be suitable on rocky planets orbiting red dwarfs. They are the most common type of star in the galaxy and are of interest to astronomers searching for exoplanets. However, planets in such systems are subject to more frequent high-speed collisions with comets and the likelihood of life appearing there is low, especially if the planets are located at significant distances from each other. “We can identify the types of systems that could be the subject of research to test different models for the origin of life. And this is another way to look at the amazing diversity of life on Earth and look for its analogues on other planets,” Anslow commented.

Astronomers have discovered a galaxy that already had a high concentration of metals a billion years after the Big Bang. Early galaxies contain mostly hydrogen and helium, but this distant galaxy is anomalously rich in metals The universe is becoming more metallic over time: in its younger days, it was composed mostly of hydrogen and helium. But recently, researchers discovered a galaxy that was well ahead of this trend and, a billion years after the Big Bang, had accumulated a high content of metals. Almost all atoms heavier than helium originate in stars, the “forges of the cosmos,” which transform primordial materials into the many different elements we see today. These "forges" process the finite amount of hydrogen and helium in the Universe. As a result, the total supply of hydrogen decreases over time, while the proportion of heavier elements (which astronomers call "metals" regardless of their actual metallic properties) increases. When astronomers look back and observe the early stages of the universe, they expect to see mostly pure hydrogen and helium. [caption id="attachment_68900" align="aligncenter" width="780"] galaxy[/caption] This prediction is generally supported by observations, and when looking at galaxies created in the first 1.5 billion years after the Big Bang, researchers most often observe clouds of gas that contain almost no metals. However, a collaboration led by Jianhao Huyang of the University of South Carolina recently discovered a contradiction to this convention: their observations of a hazy galaxy created a billion years ago showed a metal fraction higher than predicted for such a young source by more than two orders of magnitude. Astronomers have discovered a galaxy that set the trend for a high proportion of metals before anyone else Huyang and his colleagues made this discovery by observing a distant quasar called SDSS J002526.84-014532.5, which has a redshift of 5.07. Between the Earth and this source, there is a galaxy with a redshift of 4.74. As light from a quasar passes through the diffuse gas of a galaxy on its way to our telescopes, certain wavelengths of radiation are preferentially absorbed by the molecules and atoms they encounter along the way. By measuring the relative amount of this absorption, the researchers were able to determine which elements were trying to block the path of light and how dense they were. They discovered that the galaxy contains significant amounts of carbon, oxygen, magnesium, and other heavy elements. Just 1.2 billion years after the Big Bang, this galaxy already had a greater relative amount of carbon and oxygen than our own Sun, which was born many billions of years later. Models of early galaxy formation predict a significantly lower proportion of metals, even taking into account the large uncertainties of described but not yet seen first-generation stars. Like many unexpected discoveries, the authors of the present study cannot yet explain what could lead to such a significant content of heavy elements. They acknowledge that this may be because looking at this particular direction may have passed through a patch of "developed" gas, and the galaxy as a whole may be as metal-poor as expected. However, in this case, they will not be able to explain how the light passed through such a small area with exactly the composition data obtained. It may be time to reconsider models of the chemical evolution of early galaxies, or there may be something special about this particular galaxy that remains hidden.

The research team studied the planetary nebula's central star in the star cluster, determining that it had lost 70% of its mass over its lifetime. It also turned out that the star has an unusual chemical composition and does not contain hydrogen. Stars like our Sun end their lives as white dwarfs. Some of them are surrounded by a planetary nebula, consisting of gas ejected by a dying star just before the outburst. An international research team led by Professor Klaus Werner from the Institute of Astronomy and Astrophysics at the University of Tübingen studied the central star of a planetary nebula located in an open star cluster. Scientists were able to accurately determine the mass that the central star lost during its life. There are more than a thousand open star clusters in our Galaxy. Each of them includes up to several thousand stars that were formed from a dense cloud of gas and dust. “The stars in the cluster are of the same age, and this is of particular importance for astrophysics,” says Klaus Werner. They differ only in their mass. “The greater the mass of a star, the faster it consumes its nuclear fuel, burning hydrogen into helium. So the life of a large star is shorter and it turns into a white dwarf faster,” he explains. [caption id="attachment_68877" align="aligncenter" width="780"] nebula Messier 37[/caption] Observation of a star cluster shows the development of stars of different masses at the same age. “In astronomy, star clusters can be used as a kind of laboratory where we can test how correct our theories of stellar development are. One of the most uncertain aspects of the theory of stellar development is how much matter a star loses during its life. Stars like our Sun lose almost half their mass by the time they become white dwarfs. Stars eight times heavier than the Sun lose about 80% of their mass,” says the astrophysicist. The mass of white dwarfs in star clusters can be directly related to their mass at birth. Data on very young white dwarfs is especially valuable because they are the central stars of planetary nebulae. But none of their central stars in such nebulae have been studied before because they are all very distant and dim. The research team pointed one of the world's largest telescopes, the ten-meter GRANTECAN telescope, at the central star in the Messier 37 cluster and analyzed its spectrum. They were able to determine the star's mass to be 0.85 solar masses, meaning an original mass of 2.8 solar masses. How the central star of the planetary nebula Messier 37 survived the loss of 70% of its mass “The star thus lost 70% of its matter during its lifetime,” explains Werner. Another feature is its special chemical composition. There is no longer any hydrogen left on its surface. This points to an unusual event in its recent past - a short-term burst of nuclear reactions. The ability to accurately determine the start-to-end mass relationship of a star is of fundamental importance in astrophysics. It determines whether a star becomes a white dwarf, becomes a neutron star during a supernova, or becomes a black hole at the end of its life. From the ejected matter at the moment of “rebirth” of the star, new generations of stars are formed, enriched with heavy elements as products of nuclear reactions. The chemical evolution of galaxies, and ultimately the entire Universe, depends on this.

A new release of Gaia data has revealed half a million faint stars in the globular cluster Omega Centauri. This discovery helps fill gaps in maps of the galaxy and will allow scientists to study the structure of the cluster. The European Space Agency (ESA) has unveiled new and improved data about our galaxy and outer space with the release of 5 new pieces of data collected by the Gaia space telescope. Among the mission's findings, the release identified half a million dim stars in the massive Omega Centauri cluster. The new stars discovered by Gaia inhabit one of the densest regions of the sky. The Gaia mission's previous third edition of observations provided information on more than 1.8 billion stars, providing a fairly comprehensive view of the Milky Way and beyond. However, gaps remained in the map of the galaxy. In those areas that are particularly densely “populated” with stars, the usual observing regime reached its limits, which left these areas poorly unexplored - Gaia did not notice dim stars. Globular clusters are a good example of such regions. These clusters, which are among the oldest objects in the Universe, are of particular interest to scientists who study the history of the cosmos. But their bright, star-filled cores can obscure telescopes. Thus, they remain invisible regions on maps of the Universe. [caption id="attachment_66850" align="aligncenter" width="780"] Omega Centauri[/caption] To fill the gaps in Gaia's maps, it chose Omega Centauri, the largest globular cluster visible from Earth and a good example of a "typical" cluster. Instead of focusing just on individual stars, in this survey Gaia used a special observing mode, creating 2D images using the Sky Mapper tool. New Gaia Data Release: Half a Million New Stars in Omega Centauri “In Omega Centauri, we discovered more than half a million new stars that Gaia had not seen before – and that’s just in one cluster,” says lead author Dr. Katja Weingrill, Gaia project leader at the Leibniz Institute for Astrophysics in Potsdam. “The new data has allowed us to discover stars that are so close to each other that they cannot be accurately detected using the regular Gaia survey. With the new data, we will be able to study the structure of the cluster, the distribution of its constituent stars and their motion, and create a complete overview of the Omega Centauri cluster. This was using Gaia’s capabilities to their full potential,” adds co-author and member of the Gaia Collaboration, Dr. Alexey Mints. The discovery exceeds Gaia's normal capabilities, as the Sky Mapper instrument was originally intended only for calibration. The team used an observing mode designed to ensure the smooth operation of all telescope instruments. And I didn’t plan to use it for scientific research. Gaia is now exploring eight more areas using this approach, the results of which will be included in Gaia Data Release 4. The data will help astronomers better understand what's going on inside these cosmic building blocks, helping data scientists pinpoint the age of our galaxy, accurately determine its center, find out how stars change throughout their lives, clarify models of the evolution of galaxies and clarify the age of the Universe. In addition to the major discovery, the new Gaia release also reveals more than 380 possible gravitational lenses, improves the orbits of more than 150,000 asteroids within the solar system, maps the disk of the Milky Way, and characterizes the dynamics of 10,000 binary stars.