Planet formation in the constellation of the Wolf
A group of Japanese researchers discovered a site of planet formation around a young star in the Lupus Constellation. The characteristics of this object are: the protoplanetary disk that has a huge distance from the center of the star HD142527 and the dust that is concentrated almost exclusively in the upper part of the ring. Will there be rocky and gaseous planets?
Dust and gas around the star HD142527, as seen by ALMA in red and respectively green. The dust is concentrated in the upper part of the disk, where the forming of planets is possible.
A team of Japanese astronomers at the Universities of Osaka and Ibaraki managed to get concrete evidence of a planetary system around a giant young star HD142527 in the constellation of the Wolf. The observations were made with the Atacama Large Millimeter Array (ALMA) and the results of the study, published on December 25 in Publications of the Astronomical Society of Japan, is one more step in the theories of planetary formation.
The images obtained by ALMA show the cosmic dust from which the planets are born, that surrounds the young star forming an asymmetric ring (as seen in the image). By measuring the density of dust in the densest part of the ring, astronomers have found that it is highly possible the planets are forming in that region, which is very far from the center of the star (about 5 times the distance between the Sun and Neptune). It is this distance that has interested researchers, because it is the first time they discovered a site of star formation so far from the parent star in the protoplanetary disk.
Previously, researchers observed the disk around HD142527 with the Subaru Telescope and discovered a gap within the disk and the particular shape of the outer one. ALMA, however, noted the submillimeter emission from the ring of star dust. To calculate the amount of material according to the submillimeter emission strength, astronomers have had to estimate the temperature by observing the isotopic isomers of carbon monoxide. Using this information they determined that a gas giant planet or a rocky planet is forming.
The issue has a non-uniform distribution and the northern part is 30 times more luminous than the lower part of the ring. If the abundance of dust and gas is comparable to that typical universe (the mass ratio of dust and gas is 1 to 100), the denser region of the ring is massive enough to allow the formation of gas giant planets. Japanese researchers have also tested the hypothesis of the rocky planets and have thought about what they called “dust trap” in which the abundance of stellar dust is exceptionally more important than the other side of the disc. In this case, rocky planets like Earth, small bodies such as comets, or nuclei of gaseous planets can be born. In both cases, astronomers are firmly convinced that planets form in the dense part of the disk around HD142527. The next step will be to measure the exact quantity of gas in the ring to figure out which of the two hypotheses is the most likely.