The Hubble Space Telescope's latest image of the star V838 Monocerotis (V838 Mon) reveals dramatic changes in the illumination of surrounding dusty cloud structures. The effect, called a light echo, has been unveiling never-before-seen dust patterns ever since the star suddenly brightened for several weeks in early 2002.
The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a pulse of light three years ago, somewhat similar to setting off a flashbulb in a darkened room. The dust surrounding V838 Mon may have been ejected from the star during a previous explosion, similar to the 2002 event.
The echoing of light through space is similar to the echoing of sound through air. As light from the stellar explosion continues to propagate outwards, different parts of the surrounding dust are illuminated, just as a sound echo bounces off of objects near the source, and later, objects further from the source. Eventually, when light from the back side of the nebula begins to arrive, the light echo will give the illusion of contracting, and finally it will disappear.
V838 Mon is located about 20,000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy. The Hubble telescope has imaged V838 Mon and its light echo several times since the star's outburst. Each time Hubble observes the event, different thin sections of the dust are seen as the pulse of illumination continues to expand away from the star at the speed of light, producing a constantly changing appearance. During the outburst event whose light reached Earth in 2002, the normally faint star suddenly brightened, becoming 600,000 times more luminous than our Sun.
The new image of V838 Mon, taken in October 2004 with Hubble's Advanced Camera for Surveys, was prepared from images obtained through filters that isolate blue, green, and infrared light. These images have been combined to produce a full-color picture that approximates the true colors of the light echo and the very red star near the center.
Credits
NASA, ESA, and The Hubble Heritage Team (STScI/AURA);Acknowledgment: H.E. Bond (STScI)
| About The Object | |
|---|---|
| Object Name | V838 Monocerotis |
| Object Description | Nova-like variable star and surrounding light echo |
| R.A. Position | 07h 4m 4.99s |
| Dec. Position | -3° 50' 50.0" |
| Constellation | Monoceros |
| Distance | The star is ~20,000 light-years (~6 kiloparsecs) away. |
| Dimensions | The top image is 2.4 arcminutes (13.7 light-years or 4.2 parsecs) wide. |
| About The Data | |
| Data Description | These data are from the HST program : K. Noll, H. Bond, C. Christian, L. Frattare, F. Hamilton, Z. Levay, M. Mutchler, and T. Royle (STScI). |
| Instrument | HST>ACS/WFC |
| Exposure Dates | May - December, 2002 |
| Filters | F435W (B), F606W (V), F814W (I) |
| About The Image | |
| Color Info | Blue: F435W (B) Green: F606W (V) Red: F814W (I) |
| Compass Image |  |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
