This surreal picture isn’t from a special effects sci-fi movie. It is a digital composite of frames of the real Andromeda Galaxy, also known as M31, rising over a real mountain. Exposures tracking the galaxy and background stars have been digitally combined with separate exposures of the foreground terrain. All background and foreground exposures were made back to back with the same camera and telephoto lens on the same night from the same location. In the “Deepscape” combination they produce a stunning image that reveals a range of brightness and color that your eye can’t quite see on its own. Still, it does look like you could ride a cable car up this mountain and get off at the station right next to Andromeda. But at 2.5 million light-years from Earth the big beautiful spiral galaxy really is a little out of reach as a destination. Don’t worry, though. Just wait 5 billion years and the Andromeda Galaxy will come to you. This Andromeda Station is better known as Weisshorn, the highest peak of the ski area in Arosa, Switzerland.
Massive star IRS 4 is beginning to spread its wings. Born only about 100,000 years ago, material streaming out from this newborn star has formed the nebula dubbed Sharpless 2-106 Nebula (S106), featured here. A large disk of dust and gas orbiting Infrared Source 4 (IRS 4), visible in brown near the image center, gives the nebula an hourglass or butterfly shape. S106 gas near IRS 4 acts as an emission nebula as it emits light after being ionized, while dust far from IRS 4 reflects light from the central star and so acts as a reflection nebula. Detailed inspection of a relevant infrared image of S106 reveal hundreds of low-mass brown dwarf stars lurking in the nebula’s gas. S106 spans about 2 light-years and lies about 2000 light-years away toward the constellation of the Swan (Cygnus).
What happens to a star that goes near a black hole? If the star directly impacts a massive black hole, then the star falls in completely — and everything vanishes. More likely, though, the star goes close enough to have the black hole’s gravity pull away the outer layers of the star, or disrupt the star. Then most of the star’s gas does not fall into the black hole. These stellar tidal disruption events can be as bright as a supernova, and an increasing amount of them are being discovered by automated sky surveys. In the featured artist’s illustration, a star has just passed a massive black hole and sheds gas that continues to orbit. The inner edge of a disk of gas and dust surrounding the black hole is heated by the disruption event and may glow long after the star is gone.
If you stare at an interesting patch of sky long enough, will it look different? In the case of Pleiades and Hyades star clusters — and surrounding regions — the answer is: yes, pretty different. Long duration camera exposures reveal an intricate network of interwoven interstellar dust and gas that was previously invisible not only to the eye but to lower exposure images. In the featured wide and deep mosaic, the dust stands out spectacularly, with the familiar Pleaides star cluster visible as the blue patch near the top of the image. Blue is the color of the Pleiades’ most massive stars, whose distinctive light reflects from nearby fine dust. On the upper left is the Hyades star cluster surrounding the bright, orange, foreground-star Aldebaran. Red glowing emission nebula highlight the bottom of the image, including the curving vertical red ribbon known as the Eridanus Loop. The pervasive dust clouds appear typically in light brown and are dotted with unrelated stars. Almost Hyperspace: Random APOD Generator