Anti-electric universe

March 27, 2018

Planets Forming Around Forming Stars

Filed under: Uncategorized — davidlpf @ 2:28 am

http://adsabs.harvard.edu/abs/2018AJ….155…54W?utm_source=dlvr.it&utm_medium=twitter

This survey was done by ALMA telescope (Altacama Large Millimetre Array) in Chile It observes a star forming region in the constellation of Taurus 140 pc (430ly) away and is one of the closest star forming regions. The observations were done 24 stars in the m4-m7,75 spectral classes, 2 stars had there disks transiting or edge to Earth. These stars were mostly what referred to red dwarf class, small cool stars and some were brown dwarfs which are considered somewhere between a star and a planet.

The star forming region is a molecular cloud. It is called this because it is so dense that the ionization UV radiation does not penetrate the cloud and molecules of H2 still exist in and are not broken apart by the UV radiation. The problem with this is that H2 is hard to detect because it does not emit much. Usually tracer molecules are used such as CH, OH, CS and C2H2 These clouds tend be around 50 pc or. 163 ly across wit a temperature around 20 k with a density of 200-300 particles per square cm and have a mass 10 6 the mass of the sun.

The survey measured objects that are forming in this molecular cloud. This is useful because it helps us understand how stars and planets are formed. If you can see a star when the dust is just collapsing, then another further along when the disk is formed and later when the first planets are show up you can make theories and models showing all the stages of how such a system forms. These stars are have a disk rotating around a central star or are binaries. There 3 binaries known in the group and 2 now a suspect to be binary stars after this survey. Most of the stars in the survey were 1-2 million years old with a couple that might be 20 million years old, these stars burn for about trillion years so this not much of a difference, The disk tend to have 0.2% to 0.6% of that of the parent object and had a radius of 20 to 40 AU for the smaller disks to 100 AU for the larger disks.

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March 11, 2018

Hopefully the last of Winter

Filed under: Uncategorized — davidlpf @ 12:31 am

 

An apple tree, a cherry tree hedge. the tilted pair tree and a general shot in part of the yard.

March 1, 2018

Some winter scenes

Filed under: Uncategorized — davidlpf @ 12:28 am

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