Our solar system sits in a cosmic bubble of hot, sparse gas called the . This region, formed by ancient supernovas, spans 300 light-years and contains gas heated to a million degrees Kelvin.
Within this bubble, we're currently passing through a denser pocket called the . This cooler, denser region offers a unique glimpse into the interplay between our solar system and the surrounding .
The Local Hot Bubble and Local Fluff
Structure of Local Hot Bubble
Region of hot, low-density gas surrounding our solar system
Spans about 300 light-years in diameter
Gas heated to roughly 1,000,000 K
Contains around 0.001 atoms per cm³
Exhibits an irregular, non-uniform shape
Distances to its boundaries vary in different directions ( vs )
Presence of hot gas confirmed through X-ray observations (, telescopes)
Primarily composed of hydrogen and helium
Small quantities of heavier elements like carbon, nitrogen, oxygen also present
Forms part of the larger
Origin of Local Hot Bubble
Formed as a result of multiple explosions
Violent deaths of massive stars approximately 10-20 million years ago (, )
Supernova shock waves heated and compressed the interstellar gas
Generated the hot, rarefied conditions within the LHB
Stellar winds from nearby stars also played a role in shaping the LHB
Constant flow of charged particles ejected from stars (, )
Current expansion of the LHB counterbalanced by pressure from the ambient interstellar medium
Local Fluff vs Local Hot Bubble
Local Fluff (LF) is a denser pocket of interstellar gas embedded within the LHB
Our solar system presently traversing through the LF
LF exhibits a lower temperature compared to the enveloping LHB
Around 7,000 K in the LF
Significantly cooler than the 1,000,000 K in the LHB
LF possesses a higher density relative to the LHB
Roughly 0.1 atoms per cm³ in the LF
100 times more dense than the LHB (0.001 atoms/cm³)
LF primarily consists of neutral hydrogen atoms
LHB predominantly composed of ionized gas
LF likely a surviving remnant of an interstellar cloud that endured the LHB's formation
Represents a cooler, more concentrated region within the hot, diffuse LHB (, )
Interstellar Matter and Solar System Interaction
The marks the boundary where the interacts with interstellar matter
, high-energy particles from space, interact with the heliosphere and Earth's atmosphere
allows for the study of interstellar matter through in stellar spectra
particles play a role in light absorption and scattering in space
Key Terms to Review (28)
Absorption Lines: Absorption lines are dark lines that appear in the spectrum of a star or other celestial object, representing wavelengths of light that have been absorbed by atoms or molecules in the object's atmosphere. These lines provide valuable information about the chemical composition and physical properties of the object.
Antares: Antares is a red supergiant star located in the constellation Scorpius. It is one of the largest and most luminous stars visible to the naked eye, and it plays a significant role in the context of interstellar matter around the Sun.
Aquila: Aquila is a constellation located in the northern celestial hemisphere. It is one of the 88 modern constellations and is best known for containing the bright star Altair, one of the three stars that make up the Summer Triangle asterism. In the context of the topics covered in Section 20.6 Interstellar Matter around the Sun, Aquila is significant as it lies in the direction of the Sun's motion through the Milky Way galaxy.
Betelgeuse: Betelgeuse is a red supergiant star located in the constellation Orion, known for its distinctive reddish-orange hue. As one of the largest and most luminous stars visible to the naked eye, Betelgeuse has become an important subject of study in various fields of astronomy, from understanding stellar evolution to exploring the nature of interstellar matter.
Bok Globules: Bok globules are small, dense clouds of molecular hydrogen and dust found in star-forming regions of the Milky Way galaxy. These dark, opaque globules are believed to be the earliest stage of stellar formation, where gravity causes the collapse of the cloud into a new star.
Chandra: Chandra is the name of the X-ray observatory satellite launched by NASA in 1999. It is designed to observe high-energy sources in the universe, such as black holes, neutron stars, and supernova remnants, by detecting and analyzing their X-ray emissions.
Cosmic rays: Cosmic rays are highly energetic particles that originate from outer space and travel at nearly the speed of light. They consist mostly of protons, but also include heavier atomic nuclei and electrons.
Cosmic Rays: Cosmic rays are high-energy particles, primarily composed of protons and atomic nuclei, that originate from various sources in the universe and travel through space at nearly the speed of light. These particles play a crucial role in shaping the interstellar medium, interstellar gas, and the evolution of massive stars, while also providing important insights into the cosmic context for life.
Giant molecular clouds: Giant molecular clouds are vast regions of gas and dust in space, primarily composed of molecular hydrogen. They are the primary sites for star formation within galaxies.
Heliosphere: The heliosphere is a vast, bubble-like region of space surrounding the Sun, where the solar wind and the Sun's magnetic field interact with the interstellar medium. This region extends far beyond the orbits of the planets and defines the boundary between the solar system and the rest of the Milky Way galaxy.
Interstellar dust: Interstellar dust consists of tiny solid particles found in the space between stars, within galaxies. It absorbs and scatters starlight, affecting astronomical observations.
Interstellar Dust: Interstellar dust refers to the tiny solid particles that are found throughout the space between stars in a galaxy. These microscopic grains of dust are composed of various elements and compounds, and they play a crucial role in the structure and evolution of the interstellar medium, as well as the formation of new stars and planets.
Interstellar medium: Interstellar medium (ISM) is the matter that exists in the space between star systems within a galaxy. It consists of gas (both ionized and neutral) and dust, playing a crucial role in the life cycle of cosmic material.
Interstellar Medium: The interstellar medium refers to the vast expanse of gas and dust that fills the space between stars within a galaxy. It is the material that exists in the space between solar systems and plays a crucial role in the formation and evolution of stars, as well as the overall structure and dynamics of galaxies.
Ionization: Ionization is the process in which an atom or molecule loses or gains electrons, resulting in the formation of ions. This often occurs due to high energy photons interacting with atoms or molecules.
Ionization: Ionization is the process by which an atom or molecule loses or gains one or more electrons, resulting in the formation of an ion. This process is fundamental to understanding the formation of spectral lines, the spectra of stars and brown dwarfs, the composition of interstellar gas, the behavior of cosmic rays, and the nature of interstellar matter around the Sun.
Kepler’s Supernova: Kepler’s Supernova is a Type Ia supernova that was observed in 1604 within the Milky Way galaxy. Named after astronomer Johannes Kepler, it is one of the few supernovae visible to the naked eye in recorded history.
Local Bubble: The Local Bubble is a cavity in the interstellar medium filled with hot, ionized gas. It was created by supernova explosions and stellar winds from massive stars.
Local Fluff: The Local Fluff refers to the diffuse, low-density interstellar gas and dust that surrounds the Sun and our local galactic neighborhood. It is part of the larger structure known as the Local Bubble, a region of hot, rarefied gas that has been carved out of the Milky Way's interstellar medium.
Local Hot Bubble: The Local Hot Bubble is a region of hot, low-density gas that surrounds the solar system within the Local Bubble, a larger cavity of rarefied interstellar gas. This hot bubble is believed to have been created by the energy released from multiple supernovae explosions in the past, which have shaped the local interstellar environment around our Sun.
Molecular Clouds: Molecular clouds are vast, dense regions of the interstellar medium composed primarily of molecular hydrogen and other molecules. These clouds serve as the birthplace for new stars and play a crucial role in the life cycle of cosmic material throughout the universe.
Orion: Orion is a prominent and easily recognizable constellation in the night sky, named after the Greek mythological hunter. It is one of the most conspicuous and distinctive star patterns, featuring a distinctive hourglass or belt-and-sword shape that is visible throughout the world.
Rosat: Rosat is a satellite-based X-ray observatory that was launched in 1990 to study the hot, diffuse gas in the solar system and the interstellar medium surrounding the Sun. It played a crucial role in our understanding of the interstellar matter around the Sun, a topic covered in section 20.6 of the course.
Solar wind: Solar wind is a continuous stream of charged particles released from the upper atmosphere of the Sun, called the corona. It consists primarily of electrons, protons, and alpha particles.
Solar Wind: The solar wind is a constant stream of charged particles, primarily electrons and protons, that flow outward from the Sun in all directions at high speeds. This solar wind originates from the Sun's upper atmosphere, known as the corona, and interacts with the planetary bodies and interstellar medium throughout the solar system.
Spectroscopy: Spectroscopy is the study of the interaction between matter and electromagnetic radiation, which provides valuable information about the composition, temperature, and motion of celestial objects. This technique is widely used in astronomy to analyze the properties of stars, galaxies, and other cosmic phenomena.
Supernova: A supernova is a powerful and luminous stellar explosion that occurs at the end of a massive star's life cycle. It is one of the most energetic and dramatic events in the universe, releasing an immense amount of energy and ejecting vast amounts of material into space.
Wolf-Rayet Stars: Wolf-Rayet stars are a rare type of massive, hot, and extremely luminous stars that are characterized by strong stellar winds and emission lines in their spectra, indicating the presence of highly ionized elements. These stars play a crucial role in several astronomical topics, including the Doppler effect, interstellar matter around the Sun, and the evolution of stars from the main sequence to red giants.