Image Credit: Hubble Legacy Archive, NASA, ESA – Processing & Licence: Judy Schmidt
Some stars explode in slow motion. Rare, massive Wolf-Rayet stars are so tumultuous and hot that they slowly disintegrating right before our telescopes. Glowing gas globs each typically over 30 times more massive than the Earth are being expelled by violent stellar winds. Wolf-Rayet star WR 124, visible near the above image center spanning six light years across, is thus creating the surrounding nebula known as M1-67. Details of why this star has been slowly blowing itself apart over the past 20,000 years remains a topic of research. WR 124 lies 15,000 light-years away towards the constellation of Sagitta. The fate of any given Wolf-Rayet star likely depends on how massive it is, but many are thought to end their lives with spectacular explosions such as supernovas or gamma-ray bursts.
APOD NASA 01-Jul-14
Image Credit & Copyright: P. Tuthill (U. Sydney) & J. Monnier (U. Michigan), Keck Obs., ARC, NSF
Might this giant pinwheel one-day destroy us? Probably not, but investigation of the unusual star system Wolf-Rayet 104 has turned up an unexpected threat. The unusual pinwheel pattern has been found to be created by energetic winds of gas and dust that are expelled and intertwine as two massive stars orbit each other. One system component is a Wolf-Rayet star, a tumultuous orb in the last stage of evolution before it explodes in a supernova — and event possible anytime in the next million years. Research into the spiral pattern of the emitted dust, however, indicates the we are looking nearly straight down the spin axis of the system — possibly the same axis along which a powerful jet would emerge were the supernova accompanied by a gamma-ray burst. Now the WR 104 supernova itself will likely be an impressive but harmless spectacle. Conversely, were Earth really near the center of the powerful GRB beam, even the explosion’s 8,000 light year distance might not be far enough to protect us. Currently, neither WR 104 nor GRB beams are understood well enough to know the real level of danger.
NASA APOD 03-Jun-14
Image Credit & Copyright: Bob and Janice Fera (Fera Photography)
This helmet-shaped cosmic cloud with wing-like appendages is popularly called Thor’s Helmet. Heroically sized even for a Norse god, Thor’s Helmet is about 30 light-years across. In fact, the helmet is more like an interstellar bubble, blown as a fast wind from the bright, massive star near the bubble’s center sweeps through a surrounding molecular cloud. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. Cataloged as NGC 2359, the nebula is located about 15,000 light-years away in the constellation Canis Major. The sharp image, made using broadband and narrowband filters, captures striking details of the nebula’s filamentary structures. It shows off a blue-green color from strong emission due to oxygen atoms in the glowing gas.
APOD NASA 15-feb-2014
Sharpless 308 (also known as Sh2-308, S 308 or RCW 11) is a cosmic bubble of nearly 60 light-years across, located some 5,200 light-years from Earth in the constellation of Canis Major, the Greater Dog. Known as a Wolf-Rayet bubble, it has an age of about 70,000 years and an expansion velocity of about 60 kilometers per second.
Imaging telescopes or lenses: William Optics FLT 132/925
Imaging cameras: Artemis Atik 383L+
Mounts: 10 Micron GM2000 QCI
Guiding telescopes or lenses: William Optics 80 II ed triplet APO
Guiding cameras: M-Gen Guiding Kamera
Focal reducers: Tele Vue 0.8x Focal Reducer
Software: Deep Sky Stacker 3.3.3 Beta 51 DSS DeepSkyStacker, Fitswork4, Adobe Photoshop CS2
Filters: Baader Planetarium 36mm Luminance, Baader Planetarium 36mm Red, Baader Planetarium 36mm Green, Baader Planetarium 36mm Blue
Accessories: Lacerta MGEN2
Dates: Dec. 5, 2013
Locations: Sahara Sky, Marokko
Baader Planetarium 36mm Blue: 6×600″ -20C bin 1×1
Baader Planetarium 36mm Green: 5×600″ -20C bin 1×1
Baader Planetarium 36mm Luminance: 8×600″ -20C bin 1×1
Baader Planetarium 36mm Red: 5×600″ -20C bin 1×1
Integration: 4.0 hours
Autor: Stefan Westphal
AstroPhotography of the day by SPONLI
19 January 2014
We select the best works of amateur astrophotographers with details of equipment, shooting processing etc.
Image Credit & Copyright: Jeff Husted
Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive star evolution. Fast winds from this Wolf-Rayet star create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of evolution. The windblown nebula has an age of about 70,000 years. Relatively faint emission captured in the expansive image is dominated by the glow of ionized oxygen atoms mapped to violet hues.
NASA APOD 24-dec-13