Comet Catalina

 

First of all what is a comet?  A comet is an irregularly shaped piece or rock and ice that has been trapped by the sun and orbits around it, just like planets but with a more elliptical orbit.  This is what comet Catalina is, and right now it is approaching the closest point to the sun ion its orbit, when a comet approaches the closet point to its orbit called the perihelion it starts to warm up and the ice starts to melt, when this happens two different tail grow from it, one is a dust tail and the other is a gas tail.  Later one the as the comet get farther and farther it starts to rebuild the ice lost from this encounter, until the next time it get close to the sun again.  The dust tail leaves a trail in the path of the comets orbit, while the gas tail ejects in the opposite direction of the sun, so if you see the gas tails direction of a comet, then you can assume the sun is at the opposite direction of the tails path. The gas tail is actually made up of particles that have been ionized by the solar winds from the sun and have been ejected out into space. The actual rock and ice part of the comet is called the nucleus, which when heated up by the sun has its ice go from a solid state directly into a gas state, this causes a huge gas cloud to form around the nucleus called a coma, the coma can grow up to a distance of 100,000 km.  There are many more comets that orbit the sun and some can be seen more frequent than others through out the centuries.  One fun fact about these is that before anyone new what these actually where, many ancient and semi modern civilizations believed them to be omen of bad luck, which foreshadowed something bad was going to happen, but now a days we know better.  (Actual image of Catalina comet taken from North west Africa Canary Island Dec 7, 2015 by  Fritz Helmut Hemmerich)


 How a comet looks like










orbit of a comet and phase of closest approach to sun.

 source:
 http://apod.nasa.gov/apod/ap151207.html

Carbon expulsion form Martian Atmosphere

In recent days scientist have discovered why and how Mars has lost its atmosphere in the last millions of years.  Most of its atmosphere has been striped away by the sun's solar wind and its still happening today, but one question that has come up is what has happened to most of the carbonate in Mars's atmosphere.  On November 24, 2015 a team from California Institute of Technology and NASA's Jet Propulsion Laboratory published a paper showing what might have happened to all this carbonate.  Mars has a very thin atmosphere, and it has a ratio of carbon-12 and carbon-13 favoring the latter.  So what happened to all the carbon-12 where has it gone too.  One explanation is that some of the carbon-12 has been ejected into space from the top of the Martian atmosphere by solar winds, but Renyu HU and his team have found another way carbon-12 was thrown out and left the atmosphere rich in carbon-13.  The way this has happened is from the UV intensity due to the lack of an atmosphere.  Since the atmosphere is very thin more UV light form the sun enters into Mars.  When there is carbonate in the air, the UV light can actually break it apart and make carbon-12/13 with one oxygen atom, this process give energy to the atoms and actually can be enough to escape the atmosphere out into space.  Carbon-12 has a 40% chance of escape while carbon-13 has a 24% chance of escaping, favoring the carbon-12 which explains why there is more carbon-13 found with in Mars itself.

Question: What will happen when the atmosphere of the planet is completely gone?  Can the atmosphere be rebuilt?

I do not really know much this subject, but I think that once the atmosphere is completely gone the planet will have surges in temperature from night and day, it will have no winds, and would have more craters since it cant defend from meteors, and its gravity would be less as well.
The atmosphere can be rebuilt by introducing more elements into the atmosphere, but would still be blown away from solar wind, so in order to keep the atmosphere from blowing away, the magnetic field of the planet needs to be stronger, in order to defend itself from the solar wind just like Earth does. 

Professor Siana could you please correct me and answer these questions thank you.




 sources:
 http://www.nasa.gov/feature/jpl/msl/loss-of-carbon-in-martian-atmosphere-explained

Saturn's Moon Enceladus

NASA's Cassini spacecraft, has been studying Saturn's moon Enceladus and has discovered that this satellite has the potential to harbor life.  In its recent pass through over the years since Cassini arrived at Saturn in 2004 it has found some interesting facts about it. Enceladus is an icy moon assumed to be made of solid ice, but from closer looks the moon was found to be geologically active, which showed signs of activity under the ice.   



From this picture we can see how under the ice cap, there seems to be hydro thermal activity, and with a closer flyby by Cassini we will learn if this kind of activity has created a huge ocean at a global scale, and whether it has created an environment with the ingredients necessary for life. The flyby will provide more information on how habitable the moon really is, and how it behaves geologically and chemically. 

sources:
https://youtu.be/BZ1KowQXc3Y
http://www.nasa.gov/feature/jpl/seven-key-facts-about-cassinis-oct-28-plume-dive

Blue Straggler Star

In class we learned how stars of different masses tend to evolve and die off and end up as either a white dwarf, neutron star or black hole.  But we also learned that it is possible for one of these three phases to gain more mass and evolve. For example if a white dwarf surpasses the remnant mass of 1.4 solar masses, it will turn into a neutron star, because the electron degeneracy is not strong enough to support this much weight.  If a neutron star surpasses 3 solar masses, it will turn into a black hole, since neutron degeneracy cannot hold anymore.  But this occurs often when the star is part of a binary system.  A blue straggler star is a blue star that looks "hotter and bluer than they should for their advanced age." according to astronomer Natalie Gosnell.  One theory to explain this is that there is one star grows in size as it evolves into a white dwarf while the companion star is already a white dwarf.  Hence there is a transfer of mass from the swelled up star to the white dwarf, and while this happens, the initial white dwarf turn hotter and bluer while the other star turns into a white dwarf. 
Gosnell studied a star cluster called NGC 188, that has 21 blue stragglers, and she discovered that 7 of the 21 star systems had white dwarfs, and another 7 showed mass transfer between their stars, which is actual observable evidence of how blue staggers might be forming. This shows why stars that are suppose to evolve into red giants are actually turning into blue stars that burn hotter and bluer. 




Source:http://mcdonaldobservatory.org/news/releases/20151207