Portal:Radiation astronomy

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Radiation astronomy

This image is a composite of several types of radiation astronomy: radio, infrared, visual, ultraviolet, soft and hard X-ray. Credit: NASA.

Radiation astronomy is astronomy applied to the various extraterrestrial sources of radiation, especially at night. It is also conducted above the Earth's atmosphere and at locations away from the Earth, by satellites and space probes, as a part of explorational (or exploratory) radiation astronomy.

Seeing the Sun and feeling the warmth of its rays is probably a student's first encounter with an astronomical radiation source. This will happen from a very early age, but a first understanding of the concepts of radiation may occur at a secondary educational level.

Radiation is all around us on top of the Earth's crust, regolith, and soil, where we live. The study of radiation, including radiation astronomy, usually intensifies at the university undergraduate level.

And, generally, radiation becomes hazardous, when a student embarks on graduate study.

Cautionary speculation may be introduced unexpectedly to stimulate the imagination and open a small crack in a few doors that may appear closed at present. As such, this learning resource incorporates some state-of-the-art results from the scholarly literature.

The laboratories of radiation astronomy are limited to the radiation observatories themselves and the computers and other instruments (sometimes off site) used to analyze the results.

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Selected radiation astronomy

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Selected lecture

Radiation astronomy objects

Main resource: Radiation astronomy/Objects

The image shows a chain of craters on Ganymede. Credit: Galileo Project, Brown University, JPL, NASA.

Def. a hemispherical pit a basinlike opening or mouth about which a cone is often built up any large roughly circular depression or hole is called a crater.

The image at right shows a chain of 13 craters (Enki Catena) on Ganymede measuring 161.3 km in length. "The Enki craters formed across the sharp boundary between areas of bright terrain and dark terrain, delimited by a thin trough running diagonally across the center of this image. The ejecta deposit surrounding the craters appears very bright on the bright terrain. Even though all the craters formed nearly simultaneously, it is difficult to discern any ejecta deposit on the dark terrain.

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Selected theory

Stellar surface fusion

Main resources: Stars/Surface fusion and Stellar surface fusion

RHESSI observes high-energy phenomena from a solar flare. Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio.

Stellar surface fusion occurs above a star's photosphere to a limited extent as found in studies of near coronal cloud activity.

Surface fusion is produced by reactions during or preceding a stellar flare and at much lower levels elsewhere above the photosphere of a star.

"Nuclear interactions of ions accelerated at the surface of flaring stars can produce fresh isotopes in stellar atmospheres."

"This energy [10³² to 10³³ ergs] appears in the form of electromagnetic radiation over the entire spectrum from γ-rays to radio burst, in fast electrons and nuclei up to relativistic energies, in the creation of a hot coronal cloud, and in large-scale mass motions including the ejections of material from the Sun."

"The new reaction ²⁰⁸Pb(⁵⁹Co,n)²⁶⁶Mt was studied using the Berkeley Gas-filled Separator [BGS] at the Lawrence Berkeley National Laboratory [LBNL] 88-Inch Cyclotron."

²⁶⁶Mt has been produced using the ²⁰⁹Bi(⁵⁸Fe,n)²⁶⁶Mt reaction.

"Reactions with various medium-mass projectiles on nearly spherical, shell-stabilized ²⁰⁸Pb or ²⁰⁹Bi targets have been used in the investigations of transactinide (TAN) elements and their decay properties for many years. These so-called “cold fusion” reactions produce weakly excited (10-15 MeV) [1] compound nuclei (CNs) at bombarding energies at or near the Coulomb barrier that de-excite by the emission of one to two neutrons."

"The laboratory-frame, center-of-target energy used was 291.5 MeV, corresponding to a CN excitation energy of 14.9 MeV."

"At the start of the experiment the BGS magnet settings were chosen to guide products with a magnetic rigidity of 2.143 T·m to the center of the [focal plane detector] FPD. After the first event of ²⁶⁶Mt was detected in strip 45 (near one edge of the FPD), the magnetic field strength was decreased to 2.098 T·m in an effort to shift the distribution of products toward the center of the detector."

"²⁵⁸Db [has been produced] via the ²⁰⁹Bi(⁵⁰Ti,n) and ²⁰⁸Pb(⁵¹V,n) reactions [15], and ²⁶²Bh via the ²⁰⁹Bi(⁵⁴Cr,n) and ²⁰⁸Pb(⁵⁵Mn,n) reactions [13, 16]."

"Hofmann et al. at Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany, and Morita et al., at the Institute of Physical and Chemical Research (RIKEN) in Saitama, Japan, have studied the ²⁰⁹Bi(⁶⁴Ni,n)²⁷²Rg reaction [7, 17, 18]. The complementary ²⁰⁸Pb(⁶⁵Cu,n)²⁷²Rg reaction was studied by Folden et al. at the Lawrence Berkeley National Laboratory (LBNL) [19]."

"Based on the observation of the long-lived isotopes of roentgenium, ²⁶¹Rg and ²⁶⁵Rg (Z = 111, t_1/2 ≥ 10⁸ y) in natural Au, an experiment was performed to enrich Rg in 99.999% Au. 16 mg of Au were heated in vacuum for two weeks at a temperature of 1127°C (63°C above the melting point of Au). The content of ¹⁹⁷Au and ²⁶¹Rg in the residue was studied with high resolution inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). The residue of Au was 3 × 10⁻⁶ of its original quantity. The recovery of Rg was a few percent. The abundance of Rg compared to Au in the enriched solution was about 2 × 10⁻⁶, which is a three to four orders of magnitude enrichment."

References

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Selected topic

Continua

Main resource: Radiation astronomy/Continua

The 15" refractor at Comanche Springs Astronomy Campus had its finder scope (a Stellarvue 80/9D achromat) equipped with a Baader Herschel Solar Wedge and a Solar Continuum Filter for today's transit of Venus. Credit: Jeff Barton from Richardson, TX, USA.{{free media}}

Lyc photon or Ly continuum photon or Lyman continuum photon are a kind of photon emitted from stars. Hydrogen is ionized by absorption of Lyc photons. Lyc photons are in the ultraviolet portion of the electromagnetic spectrum of the hydrogen atom and immediately next to the limit of the Lyman series of the spectrum with wavelengths that are shorter than 91.1267 nanometres and with energy above 13.6 eV.

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Selected X-ray astronomy article

Jupiter shows intense X-ray emission associated with auroras in its polar regions (Chandra X-ray Observatory observatory X-ray image on the left). The accompanying schematic illustrates how Jupiter's unusually frequent and spectacular auroral activity is produced. Observation period: 17 h, 24-26 February 2003.

Not only are there apparently X-ray dark stars, but planets generally are not usually capable of X-ray luminescence. X-ray observations offer the possibility to detect X-ray dark planets as they eclipse part of the corona of their parent star while in transit. "Such methods are particularly promising for low-mass stars as a Jupiter-like planet could eclipse a rather significant coronal area."

As X-ray detectors have become more sensitive, they have observed that some planets and other normally X-ray non-luminescent celestial objects under certain conditions emit, fluoresce, or reflect X-rays.

Jupiter's strong, rapidly rotating magnetic field (light blue lines in the figure) generates strong electric fields in the space around the planet. Charged particles (white dots), trapped in Jupiter's magnetic field, are continually being accelerated (gold particles) down into the atmosphere above the polar regions, so auroras are almost always active on Jupiter. Electric voltages of about 10 megavolts, and currents of 10 megaamperes—a hundred times greater than the most powerful lightning bolts—are required to explain the auroras at Jupiter's poles, which are a thousand times more powerful than those on Earth.

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Objects

• Callisto
• Ceres
• Comets
• Dione
• Earth
• Enceladus
• Io
• Jupiter
• Mars
• Mercury
• Moon
• Neptune
• Planets
• Pluto
• Saturn
• Titan
• Uranus
• Venus
• Vesta
• Volcanoes

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Selected image

Chandra X-ray Observatory observations of the central regions of the Perseus galaxy cluster are at left. Image is 284 arcsec across. Right ascension (RA) 03^h 19^m 47.60^s Declination (Dec) +41° 30' 37.00" in the constellation Perseus. Observation dates: 13 pointings between August 8, 2002 and October 20, 2004. Color code: Energy (Red 0.3-1.2 keV, Green 1.2-2 keV, Blue 2-7 keV). Instrument: ACIS. Credit: NASA/CXC/IoA/A. Fabian et al. On the right is a composite image og the behemoth galaxy NGC 1275, also known as Perseus A, that lies at the centre of Perseus Galaxy Cluster. Hubble data from the Advanced Camera for Surveys covers visible-light wavelengths and is shown in the red, green and blue. Radio data from NRAO's Very Large Array at 0.91 m was also used. In this composite image, dust lanes, star-forming regions, hydrogen filaments, foreground stars, and background galaxies are contributions from the Hubble optical data. The X-ray data contributes to the soft but violet shells around the outside of the centre. The pinkish lobes toward the centre of the galaxy are from radio emission. The radio jets from the black hole fill the X-ray cavities. Chandra data from the ACIS covers X-ray wavelengths from 0.1771 to 4.133 nm (0.3-7 KeV).

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Selected lesson

First gamma-ray source in Triangulum Australe

Main resource: Radiation astronomy/First gamma-ray source in Triangulum Australe

The first gamma-ray source in Triangulum Australe is unknown.

The field of gamma-ray astronomy is the result of observations and theories about gamma-ray sources detected in the sky above.

The first astronomical gamma-ray source discovered may have been the Sun.

But, gamma-rays from the Sun do not penetrate far enough into the Earth's atmosphere to be detected on the ground.

The early use of sounding rockets and balloons to carry detectors high enough may have detected gamma-rays from the Sun as early as the 1940s.

This is a lesson in map reading, coordinate matching, and searching. It is also a project in the history of gamma-ray astronomy looking for the first astronomical gamma-ray source discovered in the constellation of Triangulum Australe.

Nearly all the background you need to participate and learn by doing you've probably already been introduced to at a secondary level and perhaps even a primary education level.

Some of the material and information is at the college or university level, and as you progress in finding gamma-ray sources, you'll run into concepts and experimental tests that are an actual search.

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Selected quiz

Color astronomy quiz

Main resources: Radiation astronomy/Colors/Quiz and Color astronomy quiz

Gases above Io's surface produced a ghostly glow that could be seen at visible wavelengths (red, green, and violet). Credit: NASA/JPL/University of Arizona.

Color astronomy is a lecture as part of the radiation astronomy department course development of principles of radiation astronomy.

You are free to take this quiz based on color astronomy at any time.

To improve your scores, read and study the lecture, the links contained within, and listed under See also, External links and the {{radiation astronomy resources}} and {{principles of radiation astronomy}} templates. This should give you adequate background to get 100 %.

As a "learning by doing" resource, this quiz helps you to assess your knowledge and understanding of the information, and it is a quiz you may take over and over as a learning resource to improve your knowledge, understanding, test-taking skills, and your score.

This quiz may need up to an hour to take and is equivalent to an hourly.

Suggestion: Have the lecture available in a separate window.

Enjoy learning by doing!

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Selected laboratory

Electron beam heating laboratory

Main resources: Electron beam heating/Laboratory and Electron beam heating laboratory

File:Sun in X-rays Recovered.png

This is an X-ray image of the coronal clouds near the Sun. Credit: NASA Goddard Space Flight Center.

This laboratory is an activity for you to create a method of heating the solar corona or that of a star of your choice. While it is part of the astronomy course principles of radiation astronomy, it is also independent.

Some suggested entities to consider are electromagnetic radiation, electrons, positrons, neutrinos, gravity, time, Euclidean space, Non-Euclidean space, magnetic reconnection, or spacetime.

More importantly, there are your entities.

Please define your entities or use available definitions.

Usually, research follows someone else's ideas of how to do something. But, in this laboratory you can create these too.

Okay, this is an astronomy coronal heating laboratory.

Yes, this laboratory is structured.

I will provide an example of electron beam heating calculations. The rest is up to you.

Please put any questions you may have, and your laboratory results, you'd like evaluated, on the laboratory's discussion page.

Enjoy learning by doing!

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Selected problems

Column densities

Main resource: Column densities

A region of the sky called the "Lockman Hole", located in the constellation of Ursa Major, is one of the areas surveyed in infrared light by the Herschel Space Observatory. Credit: ESA/Herschel/SPIRE/HerMES.

A column density is the number of units of matter observed along a line of sight that has an area of observation. This area has a height that is the distance to an object, or through which observation is taking place.

"A region of the sky [at right] called the "Lockman Hole", located in the constellation of Ursa Major, is one of the areas surveyed in infrared light by the Herschel Space Observatory. All of the little dots in this picture are distant galaxies. The pattern of their collective light is what's known as the cosmic infrared background. By studying this pattern, astronomers were able to measure how much dark matter it takes to create a galaxy bursting with young stars."

References

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Selected X-ray astronomy pictures

This is an X-ray image of two hot gas shells produced by supernova explosions. Although the shells appear to be colliding, it may be an illusion. Chandra X-ray spectra show that the shell of hot gas on the upper left contains considerably more iron than the one on the lower right. This implies that stars with very different ages exploded to produce these objects. The remnant on the upper left is from an old white dwarf star in a binary system, and the one on the lower right is from a much younger massive star, so the apparent proximity of the remnants is probably the result of a chance alignment.

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Fields

Fields associated with radiation astronomy include Astronomy, Astrogeology, Astrognosy, Astrohistory, Astrophysics, Atmospheric sciences, Charge ontology, Chemistry, Cosmogony, Fringe sciences, Geochemistry, Geochronology, Geology, Geomorphology, Geophysics, Geoseismology, Hydromorphology, Lofting technology, Mathematics, Measurements, Mining geology, Nuclear physics, Oceanography, Petrophysics, Radiation physics, Shielding, Spaceflights, Structural geology, Technology, Trigonometric-parallax astronomy, and X-ray trigonometric parallax

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Projects

• Astronomy Project
• Early telescopes
• Electron beam heating of the Sun
• Neutrinos from the Sun
• Stellar fission as a source of binary stars
• Sun as a binary star
• Superluminal astronomy
• X-ray classification of stars
• X-ray trigonometric parallax

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Things you can do

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