Christopher Tran
EAS 1601: Writing Assignment 1
13 October 2015
Why Giant-Planet Cores do not Spiral Towards their Parent Stars http://www.nature.com/nature/journal/v520/n7545/full/520040a.html Why are gas giant planets of exoplanetary systems at a distance of at least one astronomical unit from their host stars? As we learned in class, the gas giants form by accreting and colliding with smaller solid bodies from the disk. According to Duncan, this process of accretion can occur relatively fast for gas giants and reach critical mass that is “about 10 Earth masses”, and begins to accrete surrounding gases. The problem with this accretion process is that the growing planetismal creates a “gravitational wake” in the disk so that it will result …show more content…
The embryo moves slower in the orbit than the embryo itself. Since the gas pressure decreases with increasing distances from the star, the gradient gas pressure supports the gas parcels. The region in the gas disk relates to the embryo’s orbit, which results in the differences in gas and heat flow behind and in front of the embryo. Due to these similarities, the heating torque is positive overall. But what does the magnitude of the heating torque depend on?
Heating torque magnitude depends on the disk opacity, accretion rate, and the mass of the embryo. The disk opacity determines the distance of the energy of deposited accreted materials from the embryo itself. The accretion rate determines the rate at which energy is lost, which relates to the heating torque. Llambay says that if the embryo mass is close to the earth’s mass, the only way the heating torque overcome the tidal torque is for the accretion rate to double the embryo …show more content…
What are the conditions and mathematical equations that determine this spiraling movement? It was vaguely talked about in the article and I think that there should be more research in the movements of the planets getting consumed by the sun. It was mentioned in the article that the process will take about 100,000 years for the gas planet, and a mass about a “few earth masses,” to be consumed by the host star.
What are the threshold masses of the gas giants for it to be spiraling back into the sun? How slow does the embryo growth have to be in order for it to be considered a failed core within the 1 AU from the host star? In the research article, it was mentioned that the speed at which the gas giants accrete and their distances from the host star determine if the planet is a failed core.
What are the temperatures needed in order to have a positive heating torque? According to the mass of the gas giant, there must be different temperature thresholds for each planet in order to have that positive heating torque. There can be research for finding the temperatures needed for a gas giant to move away from its host
EAS 1601: Writing Assignment 1
13 October 2015
Why Giant-Planet Cores do not Spiral Towards their Parent Stars http://www.nature.com/nature/journal/v520/n7545/full/520040a.html Why are gas giant planets of exoplanetary systems at a distance of at least one astronomical unit from their host stars? As we learned in class, the gas giants form by accreting and colliding with smaller solid bodies from the disk. According to Duncan, this process of accretion can occur relatively fast for gas giants and reach critical mass that is “about 10 Earth masses”, and begins to accrete surrounding gases. The problem with this accretion process is that the growing planetismal creates a “gravitational wake” in the disk so that it will result …show more content…
The embryo moves slower in the orbit than the embryo itself. Since the gas pressure decreases with increasing distances from the star, the gradient gas pressure supports the gas parcels. The region in the gas disk relates to the embryo’s orbit, which results in the differences in gas and heat flow behind and in front of the embryo. Due to these similarities, the heating torque is positive overall. But what does the magnitude of the heating torque depend on?
Heating torque magnitude depends on the disk opacity, accretion rate, and the mass of the embryo. The disk opacity determines the distance of the energy of deposited accreted materials from the embryo itself. The accretion rate determines the rate at which energy is lost, which relates to the heating torque. Llambay says that if the embryo mass is close to the earth’s mass, the only way the heating torque overcome the tidal torque is for the accretion rate to double the embryo …show more content…
What are the conditions and mathematical equations that determine this spiraling movement? It was vaguely talked about in the article and I think that there should be more research in the movements of the planets getting consumed by the sun. It was mentioned in the article that the process will take about 100,000 years for the gas planet, and a mass about a “few earth masses,” to be consumed by the host star.
What are the threshold masses of the gas giants for it to be spiraling back into the sun? How slow does the embryo growth have to be in order for it to be considered a failed core within the 1 AU from the host star? In the research article, it was mentioned that the speed at which the gas giants accrete and their distances from the host star determine if the planet is a failed core.
What are the temperatures needed in order to have a positive heating torque? According to the mass of the gas giant, there must be different temperature thresholds for each planet in order to have that positive heating torque. There can be research for finding the temperatures needed for a gas giant to move away from its host