ASTRONOMICAL

PHOTOS

By: Ismael De Fuentes Sánchez

The Medusa Nebula 

2012 October 25

Braided, serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. The nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun, as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa's transforming star is near the center of the overall bright crescent shape.

The Horsehead Nebula 

2012 October 21

One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s. The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field. Bright spots in the Horsehead Nebula's base are young stars just in the process of forming

Merging NGC 2623 

2012 October 19

2012 October 19

NGC 2623 is really two galaxies that are becoming one. Seen to be in the final stages of a titanic galaxy merger, the pair lies some 300 million light-years distant toward the constellation Cancer. The violent encounter between two galaxies that may have been similar to the Milky Way has produced widespread star formation near a luminous core and along eye-catching tidal tails. Filled with dust, gas, and young blue star clusters, the opposing tidal tails extend well over 50,000 light-years from the merged nucleus. Likely triggered by the merger, accretion by a supermassive black hole drives activity within the nuclear region. The star formation and its active galactic nucleus make NGC 2623 bright across the spectrum. This sharp cosmic snapshot of NGC 2623 is based on Hubble Legacy.

A VIEW FROM NEXT DOOR

2012 October 18

Alpha Centauri is the closest star system to the Sun. The Sun is at the upper right, shining in the background of the Milky Way. The cresent in the foreground is an artist's rendering of a planet now reported oriting Alpha Centauri B, making it the closest known exoplanets. It was discover by Xavier Dumusque. This planet has the same mass as earth but is not habitable because it orbits 3.2 days, about 0.04 times the Earth-Sun distance from its parent star.

We can see too Alpha Centauri A, a star a little colder than the Sun. This photo was

captured by European Southern Observatory, L Calçada, N. Risinger.

Bibliography:

http://antwrp. gsfc. nasa. gov/ apod/