The closest star to the sun may host a planet that is very similar to Earth, according to a study by astronomers at the European Southern Observatory ESO
Follow-up articles:
- The Israeli astrophysicist's journey to Proxima Centauri
- Is there life on the nearest planet, Proxima Centauri b?
Astronomers have discovered an alien world about the size of Earth orbiting the star Proxima Centauri, which is only 4.2 light-years away from our solar system. What's even more exciting, the research team members said, is that this planet is in the star's habitable zone, the range of distances where liquid water can be stable on a planet's surface. According to the naming rules for planets outside the solar system, the star will be called Proxima b.
"We hope that these findings will inspire future generations to continue searching beyond the stars," said lead author Guiam Anglada-Escoda, a professor of physics and astronomy at Queen Mary University.
Astronomers have been intensively hunting for planets in the Proxima Centauri system for 15 years, using the Ultraviolet Visual Echelle Spectrograph (UVES) and the High Precision Radial Velocity Searcher (HARPS), both of which are mounted on telescopes at the European Southern Observatory in 'Yala.
Artist's rendering of Proxima b The planet orbiting the red dwarf Proxima Centauri. The double star Alpha Cantauri A and B appears in the image between the planet and its sun. Image: ESO / M. Kornmesser
These instruments allow researchers to detect the slight oscillations of the star caused by the gravitational influence of the planets surrounding it.
Astronomers found hints of such fluctuations as early as 2013, but the signals did not convince that they were indeed planets, the researcher said. Anglada-Escuda and a number of other researchers began the project known as the "Pale Red Dot", a tribute to Carl Sagan's famous description of the Earth as a "pale blue dot", and the fact that Proxima Centauri is a red dwarf.
"The Pale Red Spot team focused HARPS on Proxima Centauri every night from January 19 to March 31, 2016. They then combined the new data with UVES observations made from 2000 to 2008, and optical observations from 2005 to 2015, and this time the signal The existence of a possible planet came through loud and clear.
Then, after analyzing observations of the star's brightness from several other telescopes, the researchers ruled out the possibility that the signals could be caused by the changing activity of Proxima Centauri.
"The conclusion: we found a planet around Proxima Centauri," Anglada-Escoda said at a press conference.
Proxima b orbits Proxima Centauri at a distance of only 7.5 million kilometers from its star and completes one revolution every 11.2 Earth days. As a result, it is likely that the planet is gravitationally locked, meaning that it always shows the same face to its star, just as the Moon only shows one face (the side closest to Earth).
For comparison, the Earth orbits the Sun at a distance of 150 million km. However, the new planet is right in the middle of the habitable zone because red dwarfs are much cooler and smaller than stars similar to our Sun.
Not much is known about Proxima b so it is unclear how hospitable it might be to life. In fact, there are reasons to be pessimistic on that front, noted Arti Hatzes, an astronomer at the Thuringia State Observatory in Germany. Proxima Centauri fires powerful bursts at the planet, so it experiences a much higher dose of high-energy X-ray radiation than Earth, Hatss, who is not part of the discovery team, wrote in a companion paper also published in the journal Nature.
"Energetic particles associated with fireworks could erode the atmosphere or inhibit the development of primitive forms of life," Hatses wrote. "We also don't know if the planet has a magnetic field, like the Earth has, which could protect it from dangerous radiation." But a high X-ray flux does not rule out the possibility of life, Engelda-Escoda and colleagues said.
"No one denies the existence of an atmosphere, or of seas. says Andger Reiners, a professor at the Göttingen Institute for Astrophysics in Germany," he said during a press conference on Tuesday. The question of how the star's behavior in the past affected the ability to sustain life on the planet has more implications than the current level of radiation."
By the way, the team members also noticed possible signs of the existence of another planet around Proxima Centauri, which has an orbital period of between 60 and 500 days. But the second signal is much weaker and may be caused by interference."
More of the topic in Hayadan:
A planet has been discovered that is a "cousin" of the Earth
Extraterrestrial life is similar to us and closer than we thought - Prof. Omri Vandel
16 תגובות
No Ron, that's not true.
YouTube is indeed flooded with videos in which this star is supposedly seen as another bright sun in the sky, but it is only an optical illusion seen through the camera lens, here is the explanation for it -
https://sharp-thinking.com/2013/04/25/צילמתי-עבמ/
Indeed there are many religious missionaries who try to use it to convert people.
Is this the X-star they called Naybro?
Is it true that it can be seen in certain countries near the sun with the naked eye?
Eric L,
thanks for the reply.
Ganymede has nothing to do with the matter here, in my opinion. What the commenter "Enoch" wrote to you is that there may not be a strong enough magnetic field and not that the existence of a magnetic field prevents gravitational locking.
I agree with you that escape speed is critical.
This is a minimum mass as stated and it will be very interesting to see if other methods will succeed in delimiting it.
The E-ELT will start functioning perhaps in 2024. Maybe. We have been waiting for this for many years.
I would be happy if this planet was a target for TESS next year, but the chance of a transit according to the estimate is about one percent. It should be hoped that it will come true.
If the planet is rocky then indeed the possible convection mechanisms will support a more uniform temperature on the surface of the planet.
What is also very interesting is that the peak light emission from Proxima Centauri will be in the infrared range. Most likely 1-1.1 microns which means life possibilities are quite different from what we know.
Eyal,
The truth is that I just read an article that claims that at this distance the 2 resonance options are possible - both like Hema's, and 1:1. But it doesn't matter - because Ganymede, one of Jupiter's moons, also has a magnetic field (even greater than Mercury's), and is in tidal lock with Jupiter.
As mentioned, heat also has a magnetic field.
The escape velocity and history of Proxima b, in my opinion, have a much greater influence on whether life is possible or not.
In any case, according to its size, if indeed its mass is 1.3 times that of the Earth, then it also enables tectonic activity, which is probably another important element in the existence of life, since it enables the process of circulation and emission of gases from the atmosphere into the chrome.
In any case, in 2020 a new telescope with a 39 m diameter mirror should be built which, according to what I read in Nature, should allow an optical image of Proxima b.
So we will be much smarter!
A. Benner,
Very low resolution direct spectroscopy is already being done and there are already several famous examples including a recent one a few weeks ago of a Jupiter-sized planet orbiting an A-type star in a triple star system.
Eric L.,
As mentioned, the distance of the new planet is about a tenth of the distance of Hema from the Sun, so all the beautiful explanations you give for Hema do not really catch on in this case. I totally agree that it's all speculation and we don't really know what's going on there. In the end fit a model that works best. The detected signal is distinct and clear. Read the article in Nature.
As for the escape velocity, since we don't know the radius, we also don't know the escape velocity. That being said, at such a small distance from the parent star there is likely a 1:1 gravitational lock. (compared to Hama which has a ratio of 3:2).
about life So primitive life on Earth is able to survive in unimaginably harsh environments. So who knows what's there...
A]. To Eric L, thanks for the interesting information.
B]. For the very progress of the observations on Proxima B. It seems that the progress depends on a technological breakthrough, which will allow direct spectroscopy.
The progress will probably be in the form of a giant space telescope, which will consist of several synchronized space telescopes, which will create an effective lens with a diameter of s.g. of a diameter of about XNUMX meters (and even more).
Planning for such a space telescope already exists.
It seems that the current publication on the discovery of Proxima B, as well as previous publications on the discovery of Earth-like planets in our "close environment", were intended to promote the allocation of budgets for the project.
However, the importance of the giant space telescope is not only in the spectroscopy of planets but also, and perhaps mainly, in the observations of the deepest and most distant space. Such observations will entail huge breakthroughs, both in cosmological research (the size of the visible universe and dark energy) and in the study of the structure of matter and the elementary particles in the universe (dark matter).
Enoch, that's not accurate. Mercury has a stronger magnetic field than Mars and Langa, even though it is gravitationally locked.
Ganymede, a moon of Jupiter, also has a magnetic field even though it is gravitationally locked in front of Jupiter.
The reasons that Mercury (or Hema in Hebrew) does not have an atmosphere are, as I mentioned, not necessarily because of its proximity to the sun and its sensitivity to solar showers due to this distance (it has a connection but only secondary), nor because it is gravitationally locked. But because it has a very small mass, therefore the escape velocity from it is very low, and also the magnetic field it produces is not strong enough because apparently its internal dynamo mechanism is not large enough.
If Mercury were the size of the Earth, it is very possible that it would have managed to maintain an atmosphere of heavy gases, and perhaps a magnetic field strong enough to retain light gases as well. In addition, a thick atmosphere would probably also distribute the heat evenly all over this planet. But in any case it was too hot because it is not in the habitable zone of our sun.
Proxima B, on the other hand, is in the habitable zone of Proxima Centauri, and has a mass very close to that of the Earth (slightly larger even), so it is possible that it has a magnetic field (not mandatory - Venus is almost the same as the Earth in mass, but for an unknown reason it does not have magnetic field), and in any case the escape velocity there is higher than the Earth - so even light gases will have more difficulty escaping.
So you don't have to dismiss outright. What's more, I'm pretty sure that even if there are adequate conditions for life there, and there is something living on the surface of the planet, the chances are that they are not intelligent.
Just a small correction to Eric L,
The black body temperature of the Earth is about seven degrees Celsius. If you add average albedo it drops to around minus eighteen. But there is also absorption and emission back to the ground of relatively long wavelengths from greenhouse gases in the atmosphere. This actually results in an average temperature of around 14 degrees Celsius.
If the planet is gravitationally locked, it likely won't have a strong enough magnetic field to repel solar winds.
In this situation, the solar winds will blow away its atmosphere - similar to the situation on Mars.
In short, let them keep looking.
Eric L,
Thanks for the detailed response but the estimated distance of this planet is much closer to Proxima Centauri than Mercury to the Sun. And statistically red dwarfs are more violent than stars like our sun. despite a lower temperature. The X-radiation that this planet absorbs is hundreds of times greater than what the Earth absorbs and tens of times what Mercury absorbs. Therefore, there is a significant chance that the atmosphere of the planet was dispersed everywhere if there was one at all. It also depends a lot on the formation of the system. Is it a captured wandering planet? Is this a planet formed from a disc? As mentioned, everything is speculation. Also the mass of the planet is of course the minimum mass and does not represent the real mass which can be much higher.
In the hope that they will be able to perform a proper simulation of the system and perhaps be able to discover spectral traces and then it will be a tremendous breakthrough. I know from some friends who make observations at LA SILLA that the direction is to try to make images with the VLT. We will wait and see.
Arya, I didn't understand what you mean.
Eyal,
The difference between Hema and this star is in mass. The reason the planet Hema (Mercury) has no atmosphere is because it is so small. This thing + sacrifice to the sun causes 2 things:
1. Even so, it is difficult for him to hold light gases.
2. The side facing the sun heats up more, and heavier gases at such temperatures also reach the lower escape velocity than Mercury.
3. Unlike many rocky planets (Nega and Mars) Mercury, like the Earth, actually has a magnetic field. Although this magnetic field is much weaker (only 10% of that of the Earth), it is enough to stop a significant part of the particles that come from the Sun near it. The problem is that it is not strong enough to stop solar flares, which probably finished the rest of the job and scooped up what little atmosphere it might have had into space (as happened to Mars, which has no magnetic field).
Note by the way that even Langa, which does not have a magnetic field, because of its mass, and despite its proximity to the Sun, manages to maintain an atmosphere much thicker than Earth's.
I think that the fact that Mars and Venus are so different from Earth is unusual and strange.
If Venus were smaller, closer to the mass of Mars, and had a magnetic field, it would likely be very similar to Earth.
If Mars was closer to the Earth in its mass, or even slightly larger, it is likely that it would have managed to maintain its atmosphere even without a magnetic field (see Venus).
In the same way, Proxima B, right now, has a greater mass than Earth (1.3 times). This means, in relation to Mercury, some interesting things:
1. It may be that its magnetic field is stronger than Earth's, so that solar flares from Proxima Centauri are also mostly blocked.
2. Because of its greater mass, its atmosphere may be thicker. Here there is actually an advantage in solar showers - perhaps they provide the balance so that the planet does not turn into Venus 2.0 by sweeping away part of the atmosphere.
3. The fact that Proxima B's black body temperature is -40 degrees (on Earth it is -20 if I'm not mistaken), also helps here - its greater mass probably helps keep its atmosphere thicker.
In short, I think that because of its large mass, solar showers will not prevent the existence of an atmosphere. The questions that need to be asked are: What is the size of the atmosphere? Is it about Naga 2.0 or not? Is it thick enough that the temperature of a planet that is in tidal locking with its star will spread to the dark side as well? Does this planet have an active magnetic field?
All these are what will ultimately decide whether this planet is habitable or not.
In any case, in my opinion the sacrifice is big enough and the planet is intriguing enough to make an effort that maybe, just maybe, by the end of this century we will get an answer to that 🙂
There must always be one like a deer - there is order in the universe - there must be...
I don't think it will be possible to see the transit of the planet. Been trying for many years. And if the cycle is that short then you would have seen it already. Apparently the angle of inclination is problematic. Another thing is that the minimum mass is 1.3 Earth masses, so without transit and/or direct spectroscopy it will be impossible to know what the composition of the planet is. whether it is rocky or not.
collect,
Venus-like does not fit the parameters of this planet either. At this distance the planet is in a state of Tidal Locking. Like the moon and the earth. This situation is more reminiscent of Mercury. But also not exactly.
The name "Earth-like" makes headlines but, if they weren't looking for headlines, it's likely that the name "Venus-like" would be more appropriate.
Before the above discovery, there was an astronomer who said: If we find an Earth-like star at a distance close to our solar system, this will have a substantial impact on the chances that Earth-like stars are common stars in our galaxy.
There are 3 Earth-like stars in our system: Venus, Earth and Mars, and now we also know that the system closest to us has at least one planet (possibly two).
Up to now
This implies that statistically terrestrial planets are relatively common in the galaxy, and this is one of the important points of the discovery.