astronomy

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Mars is now known as the planet who lost an ocean’s worth of water. According to new results published today, about 4 billion years ago a primitive ocean on Mars held more water than Earth’s Arctic Ocean. Above’s an artist’s impression showing how Mars may have looked.

An international team of scientists used European Southern Observatoy’s Very Large Telescope, along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility, to monitor the atmosphere of the planet and map out the properties of the water in different parts of Mars’s atmosphere over a six-year period. read more here
illustration credit: ESO/M. Kornmesser/N. Risinger (skysurvey.org)

Thor’s Helmet

This stunning image shows the nebula cataloged as NGC 2359, but more commonly known as Thor’s Helmet. It does bear a striking resemblance to the headpiece worn by the Norse god, right down to the wings. The nebula, roughly 30 light-years across, is located about 15,000 light-years away in the constellation Canis Major.

Powering up this nebula is a Wolf-Rayet (WR) star known as HD 56925. WR stars are hot, massive giants late in their evolutionary cycles. This O-type giant, perhaps 20 times more massive than the Sun, has gone through a rapid loss of mass, casting most of its hydrogen out into space. The powerful stellar winds carrying this material outward shock the surrounding interstellar medium, causing it to glow. The wing structures were likely thrown off earlier by the progenitor star, while the central helmet portion of the nebula is a more recent bubble blown by the O-type blue giant.

The Thor’s Helmet nebula is not immortal. The central Wolf-Rayet star, having jettisoned most of its hydrogen outward, begins to fuse heavier elements, but that fusion process will end at iron. The outward pressure from fusion will cease, and the inward pressure of gravity will crush the star down, creating a supernova explosion. The nebula won’t survive the blast, but perhaps the resulting supernova remnant will take on an interesting shape of its own.

For a larger version of this image, go here:http://bit.ly/1KOMSEu

-JF

Image credit & copyright: Adam Block/Mount Lemmon SkyCenter/University of Arizona

Sources: 1, 2, 3

At the center of this reflection nebula is the young star V1331 Cyg. The star is starting to contract to become a main sequence star similar to our Sun. What makes V1331Cyg special is the fact that we look almost exactly at one of its poles. Usually, the view of a young star is obscured by the dust from the circumstellar disc and the envelope that surrounds it. However, with V1331Cyg we are actually looking in the exact direction of a jet driven by the star that is clearing the dust and providing this magnificent view.

Credit: ESA/Hubble, NASA, Karl Stapelfeldt (GSFC), B. Stecklum and A. Choudhary (Thüringer Landessternwarte Tautenburg, Germany)

All four stages of the rocket are visible in this time lapse photo of the NASA Oriole IV sounding rocket with Aural Spatial Structures Probe, launched from Poker Flats, Alaska

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Planet ‘reared’ by four parent stars

Growing up as a planet with more than one parent star has its challenges. Though the planets in our solar system circle just one star—our sun—other more distant planets, called exoplanets, can be reared in families with two or more stars. Researchers wanting to know more about the complex influences of multiple stars on planets have come up with two new case studies: a planet found to have three parents, and another with four.

The discoveries were made using instruments fitted to telescopes at the Palomar Observatory in San Diego: the Robo-AO adaptive optics system, developed by the Inter-University Center for Astronomy and Astrophysics in India and the California Institute of Technology in Pasadena, and the PALM-3000 adaptive optics system, developed by NASA’s Jet Propulsion Laboratory in Pasadena, California, and Caltech.

This is only the second time a planet has been identified in a quadruple star system. While the planet was known before, it was thought to have only three stars, not four. The first four-star planet, KIC 4862625, was discovered in 2013 by citizen scientists using public data from NASA’s Kepler mission.

The latest discovery suggests that planets in quadruple star systems might be less rare than once thought. In fact, recent research has shown that this type of star system, which usually consists of two pairs of twin stars slowly circling each other at great distances, is itself more common than previously believed.

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