page_title: Interstellar cloud
section_title: High-velocity cloud
hierarchical_section_title: Interstellar cloud / High-velocity cloud
caption_attribution_description: English: The pearly wisps surrounding the central star IRAS 10082-5647 in this Hubble image certainly draw the eye towards the heavens. The divine-looking cloud is a reflection nebula, made up of gas and dust glowing softly by the reflected light of nearby stars, in this case a young Herbig Ae/Be star. The star, like others of this type, is still a relative youngster, only a few million years old. It has not yet reached the so-called main sequence phase, where it will spend around 80% of its life creating energy by burning hydrogen in its core. Until then the star heats itself by gravitational collapse, as the material in the star falls in on itself, becoming ever denser and creating immense pressure which in turn gives off copious amounts of heat. Stars only spend around 1% of their lives in this pre-main sequence phase. Eventually, gravitational collapse will heat the star’s core enough for hydrogen fusion to begin, propelling the star into the main sequence phase, and adulthood. The Advanced Camera for Surveys aboard the Hubble Space Telescope captured the whorls and arcs of this nebula, lit up with the light from IRAS 10082-5647. Visible (555 nm) and near-infrared (814 nm) filters were used, coloured blue and red respectively. The field of view is around 1.3 by 1.3 arcminutes.
context_page_description: An interstellar cloud is generally an accumulation of gas, plasma, and dust in our and other galaxies. Put differently, an interstellar cloud is a denser-than-average region of the interstellar medium, the matter and radiation that exists in the space between the star systems in a galaxy. Depending on the density, size, and temperature of a given cloud, its hydrogen can be neutral, making an H I region; ionized, or plasma making it an H II region; or molecular, which are referred to simply as molecular clouds, or sometime dense clouds. Neutral and ionized clouds are sometimes also called diffuse clouds. An interstellar cloud is formed by the gas and dust particles from a red giant in its later life.
context_section_description: These interstellar clouds possess a velocity higher than can be explained by the rotation of the Milky Way. By definition, these clouds must have a vₗₛᵣ greater than 90 km s⁻¹, where vₗₛᵣ is the local standard rest velocity. They are detected primarily in the 21 cm line of neutral hydrogen, and typically have a lower portion of heavy elements than is normal for interstellar clouds in the Milky Way.
  Theories intended to explain these unusual clouds include materials left over from the formation of the galaxy, or tidally-displaced matter drawn away from other galaxies or members of the Local Group. An example of the latter is the Magellanic Stream. To narrow down the origin of these clouds, a better understanding of their distances and metallicity is needed.
  High-velocity clouds are identified with an HVC prefix, as with HVC 127-41-330.
caption: Reflection nebula IRAS 10082-5647 observed by the Hubble Space Telescope.
exif: {"Image ImageDescription": "The  pearly wisps surrounding the central star IRAS 10082-5647 in this  Hubble image certainly draw the eye towards the heavens. The  divine-looking cloud is a reflection nebula, made up of gas and dust  glowing softly by the reflected light of nearby stars, in this case a  young Herbig Ae/Be star. The  star, like others of this type, is still a relative youngster, only a  few million years old. It has not yet reached the so-called main  sequence phase, where it will spend around 80% of its life creating  energy by burning hydrogen in its core. Until then the star heats itself  by gravitational collapse, as the material in the star falls in on  itself, becoming ever denser and creating immense pressure which in turn  gives off copious amounts of heat. Stars  only spend around 1% of their lives in this pre-main sequence phase.  Eventually, gravitational collapse will heat the star\u2019s core enough for  hydrogen fusion to begin, propelling the star into the main sequence  phase, and adulthood. The  Advanced Camera for Surveys aboard the Hubble Space Telescope captured  the whorls and arcs of this nebula, lit up with the light from IRAS  10082-5647. Visible (555 nm) and near-infrared (814 nm) filters were  used, coloured blue and red respectively. The field of view is around 1.3 by 1.3 arcminutes.", "Image Artist": "", "Image Copyright": ""}