Requestioning the History of the Magellanic Stream. Star formations found leading the charge.

For decades, astronomers and scientists have believed the Magellanic clouds to be a closely related companions to our Milky Way galaxy, having orbited the galaxy several times the last billions of years. Evidence from 2002 and 2005 suggested that this was not the case, and that the clouds were moving much faster than can be explained by a bound orbit with the Milky Way. They concluded that the system was only making its first pass into our Milky Way.

However, recent discoveries have added more to the confusion of history of the Magellanic stream. An international team of researchers led by Dana Casetti-Dinescu of Southern Connecticut State University have, for the first time, discovered young stars that are enveloped in the Leading arm of the stream. The wide and irregular feature of the stream once again suggests that the cloud has had long interaction with the Milky Way.

Observation of the leading arm verified 19 young giant stars. Similar radial velocities between several of the stars suggests formation of the stars together. One star is so young (only about 1-2 million years old), that it could not have possibly been ejected from the Milky Way or the Magellanic Clouds. Finding such stars have helped scientists to determine distances to the system much more easily than before when diffuse gases had to be observed. Observations show that these clouds are extremely close to the Milky Way disk (about 40,000 light years closer than we previously thought!).

Stars form as a consequence of tidal interactions of gaseous materials and the compression of them into dense and heated systems. The travelling cloud making its collision into the diffuse gases of the Milky Way's exterior halo has created the irregularity in the leading arm, and forced the clouds of gases to compress into each other as they travel. The presence of such hot and young stars so close to the Milky Way means that the clouds of gases are moving slow enough to gravitate together and condense.  If the interaction was too violent, gases would be stripped away, and kinetic energy of the system would be too great for the potential energy to be enough to form stars. 

All of the star formation and new observations of the cloud are throwing researchers into disagreement about the past of the Magellanic stream, and to really be able to model and understand its history requires the discovery of more young stars from the system. 

http://www.skyandtelescope.com/news/Young-Stars-Lead-the-Magellanic-Stream-250790851.html

http://www.skyandtelescope.com/news/Finding-the-Source-of-the-Magellanic-Stream-220688101.html

How is progress on the Death Star?

Scientists have uncovered evidence of a star that has engulfed and destroyed a planet as it was transitioning into its red giant sequence. Lithium, which is normally very easily destroyed in stars, was found in abnormally high abundances in the advanced age star. Detection of Lithium in the stellar composition of such an old star exists as evidence that the swelling of the aging star had engulfed the orbit of a nearby planet and triggered the production of Lithium from the planet's material when it spiraled into the giant.  

More evidence is the peculiar orbit of a planet 1.6X more massive than Jupiter orbiting the red giant in a highly eccentric orbit. The orbit is similar to that of Mars at its nearest approach, with a much greater Aphelion. High eccentricity orbits are rarely found around developed star systems, and this planet's orbit is the most elliptical one detected.

Orbits with such peculiarity are generally the result of gravitational attractions between planets, and so the alteration of the destroyed planet's orbit into the growing star had disrupted the orbit of the surviving planet and slingshot it out into its strange, highly eccentric orbit.

Earth is believed to suffer a fate similar to that of the missing planet as the Sun nears the end of its main sequence and swells. Perhaps the other planets, if not destroyed as well, will be strangely affected by the missing inner planets and render our Solar System unrecognizable.

http://www.dailygalaxy.com/my_weblog/2012/08/1st-ever-death-star-discovered-weekend-feature.html

First 3-D rendered models of Supernovas' turbulent nature

W. David Arnett, Regents Professor of Astrophysics at University of Arizona and developer of a new three-dimensional model for supernovae, provides explanation to observations not accounted for by previous models. His three dimensional model shows how the turbulent mixture of elements within the stellar structure causes it to expand, contract, and spew stellar material prior to its final detonation.

Previous models depicted a stellar cloud with heavier elements in the center, with gravitation attracting the surrounding material and heating up the whole as it contracts. Intense heat creates neutrinos that escape the star and take energy away from the system. Loss of energy results in further contraction of the star and faster heating/neutrino production. Limitations of models done in one or two dimensions prevent explanation of turbulent forces, and generally depict a smooth transition into the explosion.

The new model differs with the old in that it accounts for the turbulent forces that eject stellar remnants from the star as heavy elements violently stir with the lighter, as opposed to a steady contraction. His model is able to illustrate the phenomena observed in several supernovae where the stars do not simply diminish and explode. The stars that exhibit this turbulence are fighting back against the contraction, showing multiple peaks of precursor activity before the final detonation. He concludes that we may need to reconsider our understanding of what an explosion is before we may understand this stellar phenomena.

http://www.sciencedaily.com/releases/2014/03/140318113628.htm

Today, the weather on Luhman 16 is partly cloudy with a good chance of molten iron.

Luhman-16 is a binary double brown-dwarf system located approximately 6.6 light years from Earth. Observations over the rotational period of Luhman 16B has revealed splotches of uneven surface illumination that scientists suggest are patchy clouds of varying density. This is the first time such observations have been made about a Brown dwarf, and the discovery gives scientists insight into the possible weather on giant planets with orbits so close to their stars that they are lost in the glare.

Brown dwarfs are failed stars, much cooler than our Sun, and therefore emit a majority of their black-body radiation in the long infrared wavelengths. In February 2013, Kevin Luhman aboard NASA's WISE spacecraft discovered that the third "star" to Earth, Luhman-16, was actual a binary system of two brown dwarfs. This was significant in that brown dwarfs were previously too faint and too distant to observe in such detail.

The scientists used the Very Large Telescope (haha..) in Chile to observe the patterns in Luhman 16B's atmosphere using Doppler imaging, which utilizes the variations in the intensity of blue and red shifted light from the edges turning towards and away from Earth, respectively, to map out the surface.

Although the brown dwarfs are similar in temperature (1500 and 1450 Kelvin for Luhman 16 A and B), their weather patterns differ. Luhman 16A displays a featureless atmosphere, showing no fluctuations in measured intensities. Luhman 16B, however, did have variations. These, observed over several trials, showed to be varying day-to-day.

The most shocking part of this phenomena is that the clouds are not as we see on Earth, and do not contain any water. The intense heat of the brown dwarf, along with an orbital period of only 5 hours (almost twice as fast as Jupiter, our fastest spinning planet), creates vigorous atmospheric conditions that suspend silicate particles and molten iron in the atmosphere.

http://physicsworld.com/cws/article/news/2014/jan/29/nearby-brown-dwarf-has-partly-cloudy-skies

FLASH X-ray laser from Deutsches Elektronen-Synchrotron will help to uncover details about lower atmospheres in Gas planets.

The DESY's FLASH X-ray laser has recently been experimenting X-ray bombardment of liquid hydrogen in order study the process of Hydrogen becoming a plasma. The article discusses thermal properties of Hydrogen and goes on to explain the methods undergone in their experiment that revealed a way of observing dense plasma.

X-rays are electromagnetic waves that are generally in the wavelength range of 0.1-10 nm, resulting in photon energies from 100eV to 100keV. They definitely contain enough energy in their photons to ionize Hydrogen, which has a ionization potential of only 13.6eV from 91nm EM waves, so the laser is absorbed by clouds of gaseous hydrogen through their high cross section for bound-free transitions at this X-ray wavelength.

The scientists used their X-ray pulsing laser to break apart molecular Hydrogen from a solid/liquid state and ultimately "heating" and energizing the electrons until ionization into a Hydrogen plasma. Setting their laser to a super fast pulse (around a trillionth of a second), they are able to observe the plasma as if looking at a slow motion camera, with each pulse revealing a 'photo' of information about the plasma. Understanding the discoveries they have made experimenting on Hydrogen, they are confident in the future ability of observing denser plasma like those found in deeper interiors of planets.

http://www.sciencedaily.com/releases/2014/03/140311105833.htm

Light over Time interval from Exomoon

This video shows a simulation of how an exomoon orbiting an exoplanet around a distant star would look like on graphs similar to those that we look at in class. After discovery of exoplanet's from the kepler telescopes, scientists are now capable of detecting large moons circling planets around other stars. These exomoons modify the shape, timing, and duration of the transiting eclipsing lightcurve of their host planet as they pass in front of the star. As the moon orbits the planet and the planet passes in front of the star, the light intensity (flux) of the star system drops and shows a significant blip in the light time graph. As the moon comes in front of the star along with the planet, there are different curvatures and shapes to the dip in the light intensity that would explain phenomena other than simply just a single planet eclipsing in front of the star. From watching the video, the moon has a higher inclination of orbit than the planet's flat orbit, and during certain passes in front of the star may not be in the eclipsing light change at all.

http://vimeo.com/46119423

http://www.scientificamerican.com/article/exomoons-what-one-would-look-like-from-earth/

Proxima Centauri's Path Aligning with Distant Stars will Help Reveal Its Mass

http://www.scientificamerican.com/article/proximae28099s-unprecedented-passage-when-stars-align/




The green line in the above picture traces out the path that Proxima Centauri will be taking across the expanse of the night sky. The curvature and wave-like motion of the path is due to the motion of Earth around the Sun in its orbit. Proxima Centauri in the near future will be tracing out this path across our sky and reveal secrets about its mass as astronomers analyze the interaction of the star's mass with light from much more distant stars. Through process of gravitational microlensing and analysis of the phenomena arising as the star passes in front of the others, the gravity from Proxima Centauri will bend the light and cause apparently brighter/dimmer spots and even a spread out circular pattern of these directly behind stars. This is said to be the first time we will be able to notice significant effects of this gravitational lensing outside of our own solar system.