An SiO Toroid and Wide-angle Outflow Associated with the Massive Protostar W75N(B)-VLA2
ALMA has observed the star-forming region W75N(B), containing the massive protostars VLA1, VLA2, and VLA3. VLA2 is an enigmatic protostar associated with a wind-driven H2O maser shell, which has evolved from an almost isotropic outflow to a collimated one in just 20 years, with the shell expansion halted by an obstacle located to the northeast. ALMA observations of the 1.3 mm continuum and H2CO and SiO emission show a region of ∼30” (∼39,000 AU) diameter, with 40 compact continuum sources, including VLA1, VLA2, and VLA3. The H2CO emission is mainly distributed in a fragmented structure around the three massive protostars. The SiO is highly concentrated on VLA2, indicating the presence of very strong shocks generated near this protostar. The SiO emission is resolved into an elongated structure (0.6”x 0.3”) perpendicular to the major axis of the wind-driven maser shell. The structure and kinematics of the SiO emission are consistent with a toroid and a wide-angle outflow surrounding a central mass of ∼10 M⊙, thus supporting previous theoretical predictions regarding the evolution of the outflow.
This week’s image is a veritable riot of colour and activity! It features a relatively close-by star-forming region known as IRAS 16562-3959 that lies within the Milky Way in the constellation Scorpius, about 5900 light-years from Earth.
The image shows a nebula with stars. The centre of the image from top-left to bottom-right glows brightly with light from where new stars are being formed, and is partially covered by dark dust. Coloured layers of gas and dust billow out across the rest of the image. The nebula is speckled with foreground stars with large diffraction spikes.
Massive stars play a key role in the evolution of the universe: they are the main source of heavy elements and affect the process of star and planet formation, as well as the structure of galaxies. However, we do not yet have an established model of how they are born and evolve. An international scientific team, led by the IAA-CSIC, has observed the star-forming region AFGL 5180, the cradle of many massive stars, at very high infrared resolution, allowing a census of stars in the region to be made. This study, which has been published in Astronomy & Astrophysics, has also revealed numerous outflows of gas expelled by the stars, as well as their complex morphology.
The latest image from NASA’s James Webb Space Telescope shows a portion of the dense center of our galaxy in unprecedented detail, including never-before-seen features astronomers have yet to explain. The star-forming region, named Sagittarius C (Sgr C), is about 300 light-years from the Milky Way’s central supermassive black hole, Sagittarius A*.
This spectacular image shows a region called G35.2-0.7N, which is known as a hotbed of high-mass star formation. The kind of stars that form here are so massive that they will end their lives as destructive supernovae. However, even as they form they greatly impact their surroundings. At least one B-type star — the second most massive type — lurks within the region pictured here, and a powerful protostellar jet that it is launching towards us is the source of the spectacular light show.
The image was taken with the Wide Field Camera 3 (WFC3), which is mounted on the NASA/ESA Hubble Space Telescope, and the region G35.2-0.7N lies around 7200 light-years from Earth in the constellation Aquila.
Low-mass stars, like the Sun, form from fragments of large clouds of gas and dust, which condense until a central object, or protostar, forms, growing by absorbing gas from a surrounding disc and ejecting the excess material through two jets at the poles. It was not known, however, whether the most massive stars, which can reach tens of times the mass of the Sun, form through this same mechanism. An international study, led by the IAA-CSIC, has obtained the most accurate image of the massive protostar NIRS3, which not only seems to suggest that, indeed, all stars form in the same way but also that this star alternates episodes of accretion and ejection of material.
Most stars form binary systems, in which two stars revolve around a common center. However, models of planet formation, which suggest that planets are born by the slow aggregation of ice and dust particles in protoplanetary disks around forming stars, usually consider only single stars, such as the Sun. Thus, it is still unknown how planets are born around double stars, in which the gravitational interaction between the two plays an essential role. Using the Very Large Array (radio astronomical observatory in New Mexico) and the Atacama Large Millimeter/Submillimeter Array (the largest radio telescope in the world), a scientific group led by CSIC researchers has studied the binary star SVS 13, still in its embryonic phase, and has provided the best description available so far of a binary system in formation.
The Institute of Astrophysics of Andalusia (IAA-CSIC) leads the study of the binary star SVS 13, still in its embryonic phase. Astronomers have observed primordial material that may be giving birth to three planetary systems around a binary star.
Astronomers have observed primordial material that may be giving birth to three planetary systems around a binary star in unprecedented detail.
Bringing together three decades of study, an international group of scientists have observed a pair of stars orbiting each other, to reveal that these stars are surrounded by disks of gas and dust. Research published today in The Astrophysical Journal, shows the material within the newly discovered disks could be the beginnings of new planet systems which in the future orbit the binary stars.
The Institute of Astrophysics of Andalusia (IAA-CSIC) leads a study based on data from Calar Alto Observatory (CAHA), showing the variability of the planetary nebula IC4997.
Unlike the Sun, most stars form binary systems, in which two stars revolve around a common center. Sometimes the distance between the two is so small that one of them, as it evolves into a red giant, engulfs its companion and they share a common envelope. An international team, involving the Instituto de Astrofísica de Andalucía (IAA-CSIC), has studied with the ALMA telescope a sample of fifteen unusual stars, and has found that all of them had recently undergone such an episode. The finding, published in Nature Astronomy, provides new insights into the life, death and rebirth of stars.
The gaseous, dusty disks surrounding newly born stars can reveal a wealth of information about how distant stellar systems form and evolve. In a new study, scientists have now watched the interaction of two such disks in a stellar flyby.
An international team of astronomers used two of the most powerful radio telescopes in the world to create more than three hundred images deal new details about the birthplaces of planets and the earliest stages of star formation.
The ALMA Observatory in Chile has detected dust around the closest star to the Solar System, Proxima Centauri. These new observations reveal the glow coming from cold dust in a region between one to four times as far from Proxima Centauri as the Earth is from the Sun. The data also hint at the presence of an even cooler outer dust belt and may indicate the presence of an elaborate planetary system. These structures are similar to the much larger belts in the Solar System and are also expected to be made from particles of rock and ice that failed to form planets.
Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have found new evidence suggesting that a jet of fast-moving material ejected from one young star may have triggered the formation of another, younger protostar.
Osorio et al. (2016) present the discovery of a miniature protoplanetary disk around the star XZ Tau B. This discovery was made from observations using the Atacama Large Millimeter/Submillimeter Array (ALMA). XZ Tau B is a young red dwarf star estimated to be only ~4.6 million years old. It is located ~450 light years away, and it has ~1.2 times the radius and ~0.37 times the mass of the Sun. The large radius of the star indicates that it is still in the process of contracting to its final radius. The estimated effective temperature of XZ Tau B is 3550 K.
A dwarf transitional protoplanetary disk was found around the young star XZ Tau B, located some 460 light years away. According to a research paper published online on June 9 on arXiv.org, this disk of dust is much smaller than ordinary disks observed around other stars. The newly discovered feature could be a testbed for future studies regarding the evolution of transitional disks as it showcases attributes characteristic for these objects but on a much smaller scale.
Observations using the VLA radio telescope array in New Mexico show the innermost portion of a planetary birthplace around the young star HL Tauri in unprecedented detail. Clearly visible is a lump of dust with 3 to 8 times the mass of the Earth, which represents the ideal conditions for the formation of a planet: a planetary nursery with sufficient building material for a planet somewhere between the mass of our own Earth and that of Neptune. The presence of a lump points towards a solution for a fundamental problem of planet formation: how planets can form on the limited time scale available for such processes.
HD169142 is a young star with twice the mass of the Sun and whose disk extends up to two hundred and fifty astronomical units (an astronomical unit, or AU, is a unit equivalent to the distance between the Sun and the Earth: one hundred and fifty million kilometers). The system is in an optimal orientation for the study of planet formation because the disk is seen face-on.
The first article explores the disk of HD169142 with the Very Large Array radio telescope, which can detect centimeter-sized dust grains. The results, combined with infrared data which trace the presence of microscopic dust, reveal two gaps in the disk, one in the inner region (between 0.7 and 20 AU) and another, farther out and less developed, between 30 and 70 AU.
Astronomers using the Karl G. Jansky Very Large Array (VLA) have mapped the structure of a disk of dust surrounding a young star, revealing a pair of gaps in the disk where new planets are likely forming. “We’re looking at the very early stages of planetary formation in this system,” said Mayra Osorio, of the Astrophysical Institute of Andalucía (IAA-CSIC) in Spain. The international team of scientists studied a young star designated HD 169142, nearly 500 light-years from Earth. They used the VLA to observe the star at radio frequencies of 42-48 GHz, or wavelengths of about 7 mm, a technique well-suited to detecting grains of dust surrounding the star. What they found was that the star is surrounded by a dusty disk with a radius about 240 times the Earth-Sun distance. The disk has two gaps — an inner gap ranging from just less than the Sun-Venus distance out to just under the Sun-Neptune distance, and another ranging from roughly the Sun-Pluto distance out to 67 times the Earth-Sun distance.
