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  2. Boomerang Nebula - Wikipedia

    en.wikipedia.org/wiki/Boomerang_Nebula

    The Boomerang Nebula is a protoplanetary nebula [2] located 5,000 light-years from Earth in the constellation Centaurus. It is also known as the Bow Tie Nebula and catalogued as LEDA 3074547. [ 3 ] The nebula's temperature is measured at 1 K (−272.15 °C ; −457.87 °F ) making it the coolest natural place currently known in the Universe .

  3. Stellar core - Wikipedia

    en.wikipedia.org/wiki/Stellar_core

    Once a star has converted all the hydrogen in its core into helium, the core is no longer able to support itself and begins to collapse. It heats up and becomes hot enough for hydrogen in a shell outside the core to start fusion. The core continues to collapse and the outer layers of the star expand. At this stage, the star is a subgiant. Very ...

  4. M2-9 - Wikipedia

    en.wikipedia.org/wiki/M2-9

    The nebula was imaged by the Hubble Space Telescope in the 1990s. The primary component of the central binary is the hot core of a star that reached the end of its main-sequence life cycle, ejected most of its outer layers and became a red giant, and is now contracting into a white dwarf. It is believed to have been a sun-like star early in its ...

  5. List of largest nebulae - Wikipedia

    en.wikipedia.org/wiki/List_of_largest_nebulae

    Enormous Lyα nebula (ELAN) Around the quasar UM287 at around z=2.3. Cosmic filament illuminated by the quasar. MAMMOTH-1: 1,441,000 ly (442,000 pc) [7] Enormous Lyα nebula (ELAN) The nebula is associated with the galaxy overdensity BOSS1441, [7] which is a protocluster at z=2.3. The nebula represents the circumgalactic medium. Its emission is ...

  6. Emission nebula - Wikipedia

    en.wikipedia.org/wiki/Emission_nebula

    The nebula's color depends on its chemical composition and degree of ionization. Due to the prevalence of hydrogen in interstellar gas, and its relatively low energy of ionization, many emission nebulae appear red due to strong emissions of the Balmer series. If more energy is available, other elements will be ionized, and green and blue ...

  7. Stellar corona - Wikipedia

    en.wikipedia.org/wiki/Stellar_corona

    A corona (pl.: coronas or coronae) is the outermost layer of a star's atmosphere. It is a hot but relatively dim region of plasma populated by intermittent coronal structures known as solar prominences or filaments. The Sun's corona lies above the chromosphere and extends millions of kilometres into outer space.

  8. Bubble Nebula - Wikipedia

    en.wikipedia.org/wiki/Bubble_Nebula

    NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region [1] emission nebula in the constellation Cassiopeia. It lies close to the open cluster Messier 52 . The "bubble" is created by the stellar wind from a massive hot, 8.7 [ 1 ] magnitude young central star , SAO 20575 ( BD+60°2522 ). [ 7 ]

  9. NGC 6302 - Wikipedia

    en.wikipedia.org/wiki/NGC_6302

    The structure in the nebula is among the most complex ever seen in planetary nebulae. The spectrum of Butterfly Nebula shows that its central star is one of the hottest stars known, with a surface temperature in excess of 250,000 degrees Celsius, implying that the star from which it formed must have been very large.