The transit method is a photometric method that aims to indirectly detect the presence of one or more exoplanets in orbit around a star. In 1999, the method was used to confirm the existence of HD209458b, a planet that had been discovered almost at the same time by the radial velocity method.
- What is the radial method?
- How does the transit detection method work?
- What does the radial velocity method measure?
- What is the transit method of locating exoplanets?
- Which of the following can the transit method tell us about a planet?
- Is Earth the only planet in the habitable zone?
- What is a disadvantage of the transit method?
- Why is the transit method so valuable?
- What is radial velocity formula?
What is the radial method?
The radial-velocity method for detecting exoplanets relies on the fact that a star does not remain completely stationary when it is orbited by a planet. The star moves, ever so slightly, in a small circle or ellipse, responding to the gravitational tug of its smaller companion.
How does the transit detection method work?
The transit method also makes it possible to study the atmosphere of the transiting planet. When the planet transits the star, light from the star passes through the upper atmosphere of the planet. By studying the high-resolution stellar spectrum carefully, one can detect elements present in the planet's atmosphere.
What does the radial velocity method measure?
The radial velocity technique is able to detect planets around low-mass stars, such as M-type (red dwarf) stars. This is due to the fact that low mass stars are more affected by the gravitational tug of planets and because such stars generally rotate more slowly (leading to more clear spectral lines).
What is the transit method of locating exoplanets?
Most known exoplanets have been discovered using the transit method. A transit occurs when a planet passes between a star and its observer. Transits within our solar system can be observed from Earth when Venus or Mercury travel between us and the Sun.
Which of the following can the transit method tell us about a planet?
How does the transit method tell us planetary size, and in what cases can we also learn mass and density? In the transit method, the fraction of light absorbed is the ratio of the planet's area to the star's area, so we can find the physical size of the planet.
Is Earth the only planet in the habitable zone?
Earth is the only planet in our solar system's habitable zone. Mercury and Venus are not in the habitable zone because they are too close to the Sun to harbor liquid water. However, evidence suggests that the Sun used to be much dimmer.
What is a disadvantage of the transit method?
Disadvantages. The main difficulty with the transit-photometry method is that in order for the photometric effect to be measured, a transit must occur. Not all planets orbiting other stars transit their stars as seen from Earth; a distant planet must pass directly between its star and Earth.
Why is the transit method so valuable?
An additional bonus of the transit method is that it can hint at the planets atmospheric make up, if it has one. As the planet passes through the star's light, this light also passes through the planet's atmosphere, this light then heads towards Earth and is captured in our telescopes.
What is radial velocity formula?
The radial velocity equation representing the component of velocity of binary stars in the direction of the Sun was first derived by LEHMANN-FILHES. 2 His method, which follows in brief, was the differentiation of the co-ordinate z, whose origin is at the center of motion and whose direction is along the line of sight.