Super-Earths are planets with masses of 2-10 Earths. Unfortunately, they are also easy to locate only if they are very close to their suns, so the list of planets outside the solar system is still biased and does not accurately reflect the variety of the many solar systems
Could every star that is not part of a binary or multiple star system have a planetary system? And if so how much? asks wandering planet hunter Michael Muir.
"We may not know the answer yet but we are making progress towards the answer" says Mayur that he and the team of astronomers from around Europe have discovered a star surrounded by at least three planets. He used the High Accuracy Radial Velocity Measurement of the Star (HARPS) instrument at the European Southern Observatory in La Silla, Chile. They found a triple system of three super-Earths orbiting the star HD 40307. This is the first solar system with at least three "super-Earths".
In 1995, Muir and his colleague Didier Clouse discovered the first planet outside the solar system, orbiting the star 51 Pegasi. Since then, over 270 planets orbiting other suns have been discovered, most of them orbiting stars more or less similar to our sun, most of the planets were gas giants like Jupiter and Saturn.
Using special instruments such as the HARPS spectrograph mounted on a 3.6-meter telescope at La Silla, we can now discover smaller planets, with a mass 2-10 times that of Earth," says Stephan Audrey, one of Muir's colleagues. Such planets are called super-Earths, because they are more massive than Earth and less massive than Uranus and Neptune (which each have about 15 Earth masses.)
HD 40307 is slightly smaller than the Sun and is about 42 light-years away in the direction of the southern Dorados and Pictor systems. "We were able to make very precise measurements of the velocity of the star HD 40307 over the last five years, which clearly revealed the presence of the three planets," says Muir.
The planets that are only 4.2, 6.7 and 9.4 times the mass of the Earth orbit the star in periods of 4.3, 9.6 and 20.4 days respectively.
The group announced the discovery at a conference dealing with extraterrestrial planets in France. The same group also announced the discovery of two other systems, also with the help of the HARPS spectrograph. In one of them, a Super Earth (7.5 Earth masses) orbits the star HD 181433 in 9.5 days. This system also has a Jupiter-like planet that orbits its sun for 3 years. The second system includes a planet with a mass of 22 Earths that orbits its sun in 4 days, and a Saturn-like planet with a 3-day orbital period.
"It is clear to us that these planets are only the tip of the iceberg," said Muir. "Analysis of all the stars studied using HARPS shows us that about a third of our Sun-like Saturn stars contain a system with either a super-Earth or Neptune-like planets orbiting it in a period of less than 50 days.
Planets with tight orbits and close to their sun are easier to detect than stars with wide orbits and long orbital periods. "It is more likely that there are many other planets in the system not only super-Earths and Neptune-like planets at greater distances from the Suns but also Earth-like planets that we cannot detect yet. This is in addition to the Jupiter-like planets that are already known and we may come to the conclusion that the planets are a common phenomenon" concludes Audrey.
17 תגובות
A. Ben-Ner
If you read my words carefully, you will see that I was talking about "assuming a similar density" and therefore I did not ignore the considerations you raise.
I also qualified my words under the above assumption and also wrote "must not be" which is different from "must not be".
Therefore the relationship is exactly as I described and the description includes the degree of uncertainty in it.
However, it is likely that in the smaller stars among those discovered, the density is indeed similar to that of Earth.
To Michael
I think that the relationship you mentioned between the radius, the mass
And the like - the planet's gravity is not so simple and it depends very much on the composition of the materials the planet is made of. In other words, what is the size of the iron core of the planet? .
In the existing measurement methods, although the measurement of the mass of the planet in a distant star is quite accurate, the measurement of its dimensions
The planet is not exact, so even the iron core mass calculations are a general estimate.
Friend, you have no idea how many times I had to insert the article in order for it to enter, the system went crazy at that moment (probably due to a load on the server) and it took me ten attempts for the system to accept, and it also did not respond immediately to copying the sections, so I was sure that a certain section did not enter, so I inserted it again .
Now I did a simple thing. I went to the rose file where I translated the article and reinserted it instead of the previous section.
Now it appears three times:
Twice in the section and once in the comments.
For those who didn't understand, I'm talking about the passage:
Could every star that is not part of a binary or multiple star system have a planetary system? And if so how much? asks wandering planet hunter Michael Muir.
"We may not know the answer yet but we are making progress towards the answer" says Mayur that he and the team of astronomers from around Europe have discovered a star surrounded by at least three planets. He used a device…
The following sections were duplicated at the end of the article:
Could every star that is not part of a binary or multiple star system have a planetary system? And if so how much? asks wandering planet hunter Michael Muir.
"We may not know the answer yet but we are making progress towards the answer" says Mayur that he and the team of astronomers from around Europe have discovered a star surrounded by at least three planets. He used the High Accuracy Radial Velocity Measurement of the Star (HARPS) instrument at the European Southern Observatory in La Silla, Chile. They found a triple system of three super-Earths orbiting the star HD 40307. This is the first solar system with at least three "super-Earths".
The group announced the discovery at a conference dealing with extraterrestrial planets in France. The same group also announced the discovery of two other systems, also with the help of the HARPS spectrograph. In one of them, a Super Earth (7.5 Earth masses) orbits the star HD 181433 in 9.5 days. This system also has a Jupiter-like planet that orbits its sun for 3 years. The second system includes a planet with a mass of 22 Earths that orbits its sun in 4 days, and a Saturn-like planet with a 3-day orbital period.
"It is clear to us that these planets are only the tip of the iceberg," said Muir. "Analysis of all the stars studied using HARPS shows us that about a third of our Sun-like Saturn stars contain a system with either a super-Earth or Neptune-like planets orbiting it in a period of less than 50 days.
Planets with tight orbits and close to their sun are easier to detect than stars with wide orbits and long orbital periods. "It is more likely that there are many other planets in the system not only super-Earths and Neptune-like planets at greater distances from the Suns but also Earth-like planets that we cannot detect yet. This is in addition to the Jupiter-like planets that are already known and we may come to the conclusion that the planets are a common phenomenon" concludes Audrey.
—
Besides, the first time the spectrograph was mentioned, it was misspelled "stepcrograph".
Do we know it is solid?
Nimrod:
http://en.wikipedia.org/wiki/Tidal_locking
What is this phenomenon called? So that I know where to look for information on what exactly causes this process, how long it takes, limitations, etc.
First of all, sorry for calling myself "Moshe.." I was in a hurry to write and thought it was a title.
And secondly to Nimrod: Michael means that because of their speed and proximity to the sun, when the time comes they will always face one side of them to space and one side to the sun.
To illustrate this he gave an example from our solar system, the moon, always facing the same side towards us, the image likens the moon to super earth and the earth to the sun. So it doesn't really matter to the light it gets from our sun since the earth revolves around the sun.
And Michael also talks about stars if they are close to their sun, meaning the time the star orbits around their sun, the shorter the time, the closer they are to the sun.
To Michael:
"The second is that such proximity to the sun very quickly results in the "locking" of the rotation around the axis and its coordination with the rotation around the star - similar to our moon which faces a fixed side towards the earth - so these stars also reached/will reach within a short period of time the situation where they face a fixed side towards the sun , which means they will have a side that is always hot and a side that is always frozen."
How was this locked state like on the moon created? What makes such stars lock?
The moon is close to the earth and points a fixed side to the sun, but on the other hand it is not so close to the sun and it also constantly points the same side to the sun, what are the conditions that determine this side?
my father
Still the section that starts HD 40307 is a little small...
In front of more comments
It is double
Aryeh Seter
To Lamshe:
What do you think? Should I call myself "Lalamsha" and that you in your response to the words identify yourself as "Lalamsha" etc.?
The gravity there doesn't have to be terrible. If we talk about a similar density, then gravity is directly proportional to the radius - that is, to the third root of the mass.
For the gravity to be doubled, the mass needs to be 8 times.
Remember that on Earth - it was not gravity that killed the dinosaurs.
What I do find murderous there is the fact that the stars circle the star in a few days. This has two consequences:
One is that the face of the star - on the side facing the sun - is unbearably hot (because a short "year" extends a short distance from the sun). For example in our system - the planet Hema (the closest star to the Sun) orbits the Sun in about 88 days, which is much longer than the cycles of the stars discovered and even the temperatures on the planet Hema are unbearable.
The second is that such proximity to the sun very quickly results in the "locking" of the rotation around the axis and its coordination with the rotation around the star - similar to our moon which faces a fixed side towards the earth - so these stars too have reached/will reach within a short period of time a situation where they are facing a fixed side towards the sun, Which means they will have a side that is always hot and a side that is always frozen.
2 things:
1) Moshe is not really stupid in reality, the production gave each of the contestants a role they had to play, for example: the most obvious role is the role they gave to Dan, the brat who just wants to win. And Moses was given the role of the fool.
2) Regarding the question: It could be yes, but the gravity there is double the gravity of the Earth, in the best case, and even though they are built in the same structure as the Earth, this does not mean that there is necessarily water, oxygen, or a reasonable temperature for developed animals such as mammals, reptiles and birds Maybe there is a unicellular name at best.
As a fool who doesn't understand that much...that means there is a situation where you can actually live there right???
thanks for the correction. sweater.
You wrote the article twice...