Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: alright1234 on 23/05/2019 23:42:49
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Chilean astronomers discovered a planet orbiting the star Proxima Centauri using the La Silla land based telescope (Escude, p. 408) based on the dimming that occurs when a 4.22 ly planet propagates in front of the star Proxima Centauri but the Hubble proves the intensity variation of a 4.22 ly star is caused by the earth's atmosphere.
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but the Hubble proves the intensity variation of a 4.22 ly star is caused by the earth's atmosphere.
Source?
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All stars are in motion (compared to other stars).
Perhaps you are referring to the use of the Doppler shift method of measuring the velocity of a star? With high-resolution spectroscopy on a big telescope, it is possible to measure the small changes in the velocity of a star as a planet orbits the star. This is how Proxima Centauri b was discovered.
The Hubble telescope also has a spectroscope, but it is mainly intended to find the chemical composition of stars, and speeds of galaxies. It doesn't have the spectral resolution (or the light collection area) to detect the subtle effects of a planet on its parent star.
Because this planet does not pass between us and the star, it does not cause any dimming, and cannot be detected by Hubble.
See: https://en.wikipedia.org/wiki/Proxima_Centauri_b
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Chilean astronomers discovered a planet orbiting the star Proxima Centauri using the La Silla land based telescope (Escude, p. 408) based on the dimming that occurs when a 4.22 ly planet propagates in front of the star Proxima Centauri but the Hubble proves the intensity variation of a 4.22 ly star is caused by the earth's atmosphere.
1. The new planet, for now, is just a candidate. Further investigation will be needed to confirm it.
2. It was not detected by a dimming of the star as the planet passed in front of it, but by the slight "wobble" it causes in the star's motion. Planets and their parent stars orbit a common center of mass known as the barycenter. This barycenter will be closer to the star than it is the to the planet due to the difference in their masses (in the case of the Sun and Jupiter, it is just outside of the Sun's surface. Proxima Centauri is a small red dwarf, so it doesn't take as large a planet to cause a measurable wobble. The potential detection was made by carefully examining 17 yrs worth of observations. It's not like they just looked at the star and said, "Ooh, a new planet!"
3. While one method of detecting a planet is by it passing in front of it star and causing it to dim, Astronomers are well aware that there are other effects that could cause an observed dimming of the star, so they never rely on just a single dimming event. These other events tend to be more random, while a planet passing in front of the star would happen the same time apart each time. In addition, the light curve of the dimming provides additional evidence, by ruling out other periodic events that could be the cause.