Astronomy Picture of the Day Search Results for "V838 Mon"

APOD: 2022 June 26 - Light Echoes from V838 Mon
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became one of the brighter stars in the Milky Way Galaxy in early 2002. Then, just as suddenly, it shrunk and faded. A stellar flash like this had never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the featured image from the Hubble Space Telescope is actually an outwardly expanding light echo of the original flash. In a light echo, light from the flash is reflected by successively more distant surfaces in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter.

APOD: 2014 June 17 - V838 Light Echo: The Movie
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon suddenly became one of the brightest stars in the entire Milky Way Galaxy. Then, just a few months later, it faded. A stellar flash like this has never been seen before -- supernovas and novas expel a tremendous amount of matter out into space. Although the V838 Mon flash appeared to expel some material into space, what is seen in the above eight-frame movie, interpolated for smoothness, is actually an outwardly moving light echo of the flash. The actual time-span of the above movie is from 2002, when the flash was first recorded, to 2006. In a light echo, light from the flash is reflected by successively more distant ellipsoids in the complex array of ambient interstellar dust that already surrounded the star. Currently, the leading model for V838's outburst was the orbital decay and subsequent merging of two relatively normal stars. V838 Mon lies about 20,000 light years away toward the constellation of Monoceros, while the largest light echo above spans about six light years in diameter.

APOD: 2013 March 17 - Light Echoes from V838 Mon
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this had never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above image from the Hubble Space Telescope is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter.

APOD: 2011 December 4 - Light Echoes from V838 Mon
Explanation: For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this had never been seen before. It's true that supernovae and novae expel matter out into space. But while the V838 Mon flash appears to expel material into space, what is seen here is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of Monoceros the unicorn. In this Hubble Space Telescope image from February 2004, the light echo is about six light years in diameter.

APOD: 2009 November 22 - Light Echoes from V838 Mon
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this has never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above image from the Hubble Space Telescope is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter.

APOD: 2008 February 3 - Light Echoes from V838 Mon
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this has never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above image from the Hubble Space Telescope is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter.

APOD: 2006 November 3 - V838 Mon: Echoes from the Edge
Explanation: Variable star V838 Monocerotis lies near the edge of our Milky Way Galaxy, about 20,000 light-years from the Sun. Still, ever since a sudden outburst was detected in January 2002, this enigmatic star has taken the center of an astronomical stage. As astronomers watch, light from the outburst echoes across pre-existing dust shells around V838 Mon, progressively illuminating ever more distant regions. This stunning image of swirls of dust surrounding the star was recorded by the Hubble Space Telescope in September of this year. The picture spans about 14 light-years. Astronomers expect the expanding echoes to continue to light up the dusty environs of V838 Mon for at least the rest of the current decade. Researchers have now found that V838 Mon is likely a young binary star, but the cause of its extraordinary outburst remains a mystery.

APOD: 2005 November 27 - Light Echoes from V838 Mon
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this has never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above image from the Hubble Space Telescope is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter.

APOD: 2005 February 4 - V838 Mon: Light Echo Update
Explanation: Expanding light echoes continue to illuminate the dusty environs of V838 Monocerotis, mysterious variable star near the edge of our Galaxy. This stunning image, produced from Hubble data recorded in October of 2004, adds to a unique series of space-based, high-resolution views. After detecting a sudden outburst from the star in 2002, astronomers have followed the flash expanding at the speed of light through pre-existing dust clouds surrounding the reddened variable star. While the expanding light echoes are dramatic, astronomers have struggled to understand where V838 Mon itself fits into the stellar life cycle. Studies indicate the V838 Mon is a young binary system with a massive star responsible for the outburst. The Hubble image spans about 14 light-years at the estimated 20,000 light-year distance to V838 Mon.

APOD: 2004 November 25 - What the Hubble Saw
Explanation: In this striking 41 inch by 38 inch quilt, astronomy enthusiast Judy Ross has interpreted some of the Hubble Space Telescope's best galactic and extragalactic vistas. Featured in past APODs, clockwise from the lower right are; the Red Rectangle Nebula, NGC 2392, the Sleeping Beauty Galaxy, V838 Monocerotis - the Milky Way's most mysterious star, and supernova remnant N49 - the cosmic debris from an exploded star. Of course, quilts have been used historically to represent astronomical concepts. And while inspired by the images of the cosmos that she incorporates into her quilts, Ross reports that she is still a little daunted by the intricacies of the Cat's Eye Nebula revealed by the Hubble's sharp vision.

APOD: 2004 March 5 - V838 Mon: Echoes from the Edge
Explanation: Variable star V838 Monocerotis lies near the edge of our Milky Way Galaxy, about 20,000 light-years from the Sun. Still, ever since a sudden outburst was detected in January 2002, this enigmatic star has taken the center of an astronomical stage while researchers try to understand where it fits into the picture of stellar evolution. As light from the stellar flash echoes across pre-existing dust shells around V838 Mon, its appearance changes dramatically. Revealed in a sharp snapshot recorded in February by the Hubble's Advanced Camera for Surveys, this portion of the dust shell is about six light-years in diameter. But because light reflected from the dust follows only a slightly indirect path compared to the direct line-of-sight to the star, the light echoes visible now are only lagging about two years behind the outburst itself. Astronomers expect the expanding echoes to continue to light up the dusty environs of V838 Mon for at least the rest of the current decade.

APOD: 2003 December 5 - Startling Star V838 Mon
Explanation: Variable star V838 Monocerotis startled astronomers in January of 2002, undergoing a dramatic outburst like no other variable star known. Followed closely by ground-based instruments and the Hubble Space Telescope over the following months, it was soon realized that the quickly evolving dusty nebula surrounding V838 Mon was in fact made visible by "light echoes" from the outburst. Remarkably, as light from the outburst plays across layers of pre-existing circumstellar material, it gives the surrounding nebulosity the illusion of expanding "faster than light". Though the nebula's visible appearance changes dramatically over a period of months, it is actually at least 6 light years in diameter. A good astrophysical explanation for V838 Mon's outbursting behavior is still unknown but astronomers continue to follow the mystery star. This gorgeous image, based on data recorded on October 21 with the US Naval Observatory's 1.55 meter telescope, adopts the color scheme used in previous Hubble images for easy comparison.

APOD: 2003 April 2 - V838 Light Echo: The Movie
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy. Then, just as suddenly, it faded. A stellar flash like this has never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above four-frame movie is actually an outwardly moving light echo of the bright flash. The actual time-span of the movie is 8 months during 2002. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of Monoceros, while the largest light echo above spans about six light years in diameter.

APOD: 2003 March 27 - Light Echoes from V838 Mon
Explanation: Nominated for most mysterious star in the Milky Way, V838 Monocerotis briefly became one of the brightest stars in our galaxy. Its outburst discovered in January 2002, observations have indicated that V838 Mon somehow transformed itself over a period of months from a small under-luminous star a little hotter than the Sun, to a highly-luminous, cool supergiant star -- defying the conventional understanding of erupting stars and stellar life cycles. In this spectacular image, one of a series recorded last year by the Hubble Space Telescope, the dimmed V838 Mon is surrounded by an "expanding" nebula. But the nebula is actually a series of light echoes from formerly unseen shells of dust up to light-years in diameter. Previously ejected, the intricate shells progressively reflect light as it reaches them from V838 Mon's outbursts. Astronomers anticipate that light echoes from farther out in the dust envelope will continue to be visible until about 2010. Some estimates now place V838 Mon about 20,000 light-years from planet Earth.

APOD: 2002 October 3 - V838 Mon: Mystery Star
Explanation: A leading candidate for the most mysterious star found in recent times is variable star V838 Monocerotis. At a distance of about 8,000 light-years, V838 Mon was discovered to be in outburst in January of this year. Initially thought to be a familiar type of classical nova, astronomers quickly realized that instead, V838 Mon may be a totally new addition to the astronomical zoo. Observations indicate that the erupting star transformed itself over a period of months from a small under-luminous star a little hotter than the Sun, to a highly-luminous, cool supergiant star undergoing rapid and complex brightness changes. The transformation defies the conventional understanding of stellar life cycles. A most notable feature of V838 Mon is the "expanding" nebula which now appears to surround it. Seen above in two separate images from the South African Astronomical Observatory's 1 meter telescope, the nebula is probably a light echo from shells of formerly unseen material lost by the star during its previous evolution. Light-years in diameter, the shells progressively reflect the light from V838 Mon's outbursts, providing an opportunity to look back at the history of this remarkable star's behaviour.