Friday, April 29, 2011

Things that go Boom!

It is believed, that stars at the end of their lives have only 3 possible outcomes.   They either become a white dwarf for low mass stars, a neutron star for more massive stars and for even more massive stars then a new stellar blackhole is born.

Which bring us to the topic of today's blog, which sheds light to the question: What is a Type Ia Supernova?    Type Ia Supernova explains what happens when a white dwarf (the remnant of a low mass star) has a companion star that 'dumps' material onto the white dwarf.    You might find surprising, that a star dumps material onto a star remnant in a binary system.  The easier way to explain this phenomenon, is to think of what happens when we try to put things into space.    If you want to have something in space that stays in orbit between the Sun and the Earth without the need to use any energy to keep it in orbit, you need to put it at a distance between the Sun and the Earth where their mutual gravitational forces cancel out.    If you can picture this, then it won't be a stretch to understand what happens when a star orbits too close to its white dwarf companion.  Material from the star will be pulled gravitationally by the white dwarf and that material is now on the surface of the white dwarf.

Unfortunately, white dwarfs can handle so much material from its companion and when its mass reaches 1.4 solar masses, it blows itself into smithereens. This explosion is what is called a Type Ia Supernova. Back in 1572, Tycho Barhe, a danish astronomer, studied this very intense new star on the sky.   It happened that he was looking at what we now know as the Tycho Supernova.   Just recently, astronomers have confirmed that the Supernova was due to a companion dumping material onto it.  For more details you can read Sky and Telescope article and for the more ambitious here is the recent paper.

Sunday, April 24, 2011

Kepler Data Release Q2 - Mass vs Radius

The Kepler Space Telescope has been looking at the same area of the universe for over a year.   The main science goals of this project are aimed to find "Earth-Like" planets and measure its orbital characteristics.  There is a wealth of information for those interested in the details of this space mission on the Kepler website.   Kepler detects planets in our Galaxy by continuously taking snapshots of the same area of the sky and comparing the brightness of the stars in the time series.   This allows scientists to plot light curves, which are nothing but graphs of the intensity of the star vs time.   For todays' blog, I want to share with you a simple example of the type of science that can be done with the data.

The image shows a plot of mass vs. radius of the host stars detected by Kepler that might host a planets.  It is interesting that most of the stars targeted by Kepler are "clumped"  at the 1 solar radius and 1 solar mass region of the plot.   This by no means is a coincidence.  NASA Discovery Mission #10 is targeted to find planets in what we have colloquially dubbed the "Habitable Zone", which is the area around the host star that shelters Earth like temperatures.  Another feature not obvious from the data but clearly seen on the plot is the trail of host stars between 0.5-0.75 Rsun with mass of 0.4-0.9 Msun , although not as numerous as the "clump".   It would be interesting to find out how similar are the planet characteristics of the trail host stars vs the clump stars.  Perhaps there are correlations that can be inferred from just a simple plot like the one above.


Friday, April 22, 2011

An so it begins... Not with a Bang but with a Pod!

It all starts with the place where science, art and entertainment will all mix together to brew the perfect astronomical potion!   Today I finished putting together my Skyshed Pod where a .3 meter Meade LX200 ACF and an a Meade 80mm APO will be housed in for my future astronomical observations.

Oh yes, I forgot to mention, this is all because I love astronomy.  Hopefully this is the beginning of a set of new astronomical adventures.   So you may ask, what do I plan to observe first?   Well, there is a long list of Messier objects in queue.   But that would be mostly for fun and to let me dive into the art of astrophotography.   Then there are some scientific goals in mind, like looking at transiting exoplanets.  I have a few ideas for future viewing but that will be a topic of a different blog.

For now I just want to say that, putting together the perfect observatory has been a journey of at least 4 months, of research of what to buy, what to do, how to build a deck, how to run electricity outdoors, building permits stories and best of all getting all the family invested in the project.  This could not have been done without the support of my lovely wife who put aside her hobbies and "free time" to help me put together the new house of my telescopes.

Stay tuned!