The ALMA is probably the best telescope for observing planets. ALMA was the first telescope to peer inside the disks surrounding young stars. Our knowledge of the entire process is still in its infancy, but ALMA has advanced our understanding of the planet-forming process.
According to new observations, chaos and disorder are part of the process. Astronomers using ALMA have observed a star tearing a chunk away from a planet-forming disk.
What effect will it have on planetary formation?
A team of researchers led by an astronomer at the University of Victoria made a discovery. The paper is titled "A likely flyby of Z CMa caught in action." Their paper was published in the journal Nature Astronomy.
The left-over material in a disk around a star is called a Protoplanetary Disk. Planets are formed from that material. There are a lot of questions about how they form.
ALMA was the first to observe the process. Astronomers using ALMA imaged the disk around the young star in greater detail than before. Scientists interpreted the gaps in the disk as being where planets are forming, sweeping up gas and dust and leaving a gap in the process.
This is the most sharp image ever taken by ALMA, which is sharper than the NASA/ESA Hubble Space Telescope. It shows a disc around a young star. There are new ALMA observations that show the substructures of the disc that have never been seen before. ALMA is image credit.
ALMA still looks into the disks. A team of researchers used ALMA and the VLA to examine the disk around the Z Canis Majoris star system. They saw the aftermath of the stellar interloper. The interloper was not part of Z CMa. The disk structure of Z CMa was warped and stretched out.
The constellation Canis Major has a group of stars called Z CMa. Astronomers thought Z CMa was a pair, but they found two more probable stars. The stars in Z CMa are young. planets haven't formed yet The stars are in their mass-accretion phase.
The CMa system can be seen through different telescopes and at different wavelength. The main pair is in the center and the streamer is stretching down and to the right. The streamer is 2000AU long. The image is from the book "Dong et al.
It's equivalent to capturing lightning strike a tree.
>
The University of Victoria has a study Principal Investigator.
Astronomers know more about stellar fly-bys than we do. They are difficult to see, so researchers only observed a few of them. It is like trying to watch lightning strike a tree.
It is difficult to getObservational evidence of flyby events because they happen fast and it is difficult to capture them in action. The principal investigator on the new study said that what they have done with their ALMA Band 6 and VLA observations is equivalent to lightning striking a tree. The discovery shows that close encounters between young stars do happen in real life, and they are not just theoretical situations seen in computer simulations. Prior observational studies had seen flybys, but hadn't been able to collect the comprehensive evidence we were able to obtain of the event at Z CMa.
Scientists have captured an object breaking and entering into a developing star system for the first time. Combining observations from ALMA and several other facilities gave them a complete understanding of the disruption caused by this person. A long stream of gas stretching out from the disk surrounding Z Canis Majoris was created. Scientists don't know what will happen to the birth of planets in the star system.
ALMA, S. Dagnello, and NAOJ are the credit recipients.
The streamer's origin has been a puzzle.
>
A likely flyby of Z CMa caught in action.
Astronomers have observed the stream before and wondered about it. The authors point out in their paper that the streamer's origin has been a long-standing puzzle. The streamer could be a wall of a cavity carved out by the outflow of gasses, or a remnant of a cloudlet.
The point source at the end of the streamer is a new development.
A point source is astronomy jargon for a star. The researchers found a point source at about 4700 astronomical units from Z CMa. The source is at the end of a stream of gas and dust. The point source was seen as the interloper and the stream as the effect. The team says that point source C hasn't been seen yet. Their initial observations show that it is a one million-year-old planetary-mass object or a solar-mass young stellar object shrouded by gas and dust.
The disks of two stars in the Z CMa system were disrupted by flybys, which may have led to an amplification of the sound in the host disk.
Our Sun is not the norm. Most stars are in pairs. Disk disruptions are not rare in those systems. The disks are disrupted by the companion stars. This makes Z CMa stand out.
The image is from 2005 and shows the streamer. The team thought the point source C was the interloper that created the streamer. The image is from the book "Handbook of Computational Linguistics" by Keck, Dong, and others.
An astronomer at the Institute of Astronomy and Astrophysics at the Academia Sinica in Taiwan is a co-author on the paper. The press release stated that stars do not form in isolation. The twins, or even triplets or quadruplets, born together may be attracted to each other. During these moments, some material on the stars' disks may be stripped off to form gas streams that provide clues to the history of past stellar encounters.
The Solar System has had disruptive events. There have been other events that have shaped the planets, but no stellar fly-bys. Jupiter's migration changed the course of events in our system. A collision between the Earth and a planet created the Moon. Disruptions shape solar systems. The planets were already formed when these events took place.
What does a stellar flyby mean for planetary formation? What are the long-term effects?
There are pros and cons to flybys as they affect the material distribution in the disk, and in general we could think of them as a shake up of the system.
>
The University of Victoria has a study Principal Investigator.
At this point, that is open to speculation. In an e-mail exchange with Universe Today, the lead author talked about some possibilities. He said that we don't know much about the effects yet.
There are pros and cons to flybys as they affect the material distribution in the disk, and there could be both.
The analogy was made to building something out of wooden blocks. That is bad if the block structure is knocked over. But what if we don't build something out of wooden blocks but make a stir-fry? It could result in a better stir-fry.
If the disk had not been perturbed, pieces of material could run into each other after a flyby, and they wouldn't have a chance to meet. This could be good for growing objects to larger sizes.
That is only one possible outcome. If the young system was already forming planets, it could destroy them. If pebbles or larger objects have already formed, a flyby event may cause them to collide with each other, and those collision may destroy already formed objects, in which case the perturbations are not so good.
The frost line divides the solar system into regions. The frost line is near the asteroid belt. Outside the belt are gas giants and ice dwarfs, like Pluto. What would a shift in the frost line mean? The image is from NASA.
How could these flybys affect the star? The Z CMa system had an interloper. Could the solar system's frost line be affected by the outbursts? The frost line might be pushed further out.
I am not sure if we could simply classify them as good or bad for planet formation because of the complicated nature of the events.
>
The University of Victoria has a study Principal Investigator.
For a period of time, the star becomes a lot brighter because of flyby events. The frost lines would be pushed further from the star. Ices can melt or evaporate, and droplets and Molecules can interact with each other in the air. I am not sure if we could simply classify these events as good or bad for planet formation, because they are so complicated.
The evolution and growth of young star systems throughout the galaxy helps scientists better understand our own Solar System's origin. Critical evidence of what might have happened in the early development of our own Solar System is long gone, so studying these types of events gives a window into the past. Watching these events in a star system gives us the information we need. This may have happened to our Solar System. The first evidence to solve the mystery has been given by VLA and ALMA, and the next generations of these technologies will open windows on the Universe that we have only dreamed of.
There is no question that a flyby like this one would affect the system. What exactly those effects are is an open question and one that Dong would like to address in future work.
The exact effect on a system may depend on the stage of planet formation in that system, and I suppose what we can say is that flyby events to have some profound impacts on planet development.
More:
All Rights Reserved © 2024
