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

A view of 4C 71.07 from observations by the Burst and Transient Source Experiment. This helped convince scientists that they were studying data from the quasar and not some other source in the neighborhood.

In visible light, 4C 71.07 is less than impressive, just a distant speck of light. It's in radio and in X-rays - and now, gamma rays - that this object really shines. 4C 71.07 is its designation in the 4th Cambridge University catalog of radio sources. 4C 71.07 has a red shift of z=2.17, putting it about 11 billion years away in a 12 to 15-billion year-old universe (using z=1 as 5 billion light years).

A quasi-stellar radio source (quasar) is a very energetic and distant galaxy with an active galactic nucleus (AGN). QSO 0836+7107 is a Quasi-Stellar Object that emits baffling amounts of radio energy. The radio signal is caused by electrons spiraling along the magnetic fields. These electrons can also interact with visible light emitted by the disk around the AGN or the black hole at its center, and that pumps them to emit X- and gamma-radiation.

On board the Compton Gamma Ray Observatory (CGRO) is the Burst and Transient Source Experiment (BATSE) which detects in the 20 keV to 8 MeV range. QSO 0836+7107 or 4C 71.07 was detected by BATSE as a source of soft gamma rays and hard X-rays. "What BATSE has discovered is that it can be a soft gamma-ray source". QSO 0836+7107 is the faintest and most distant object to be observed in soft gamma rays. It has already been observed in gamma rays by the Energetic Gamma Ray Experiment Telescope (EGRET) also aboard the Compton Gamma Ray Observatory.

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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

This seven-million-cubic-foot super-pressure balloon is the largest single-cell, super-pressure, fully-sealed balloon ever flown. Credit: NASA.{{free media}}

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Selected lesson

First X-ray source in Andromeda

Main resource: First X-ray source in Andromeda

File:Andromeda+Galaxy+in+X-rays.jpg

This is an X-ray image of the Andromeda galaxy. Credit: ESA/XMM-Newton/EPIC/W. Pietsch.

The first X-ray source in Andromeda is not known. This lesson is also a research project that needs your help. And, in exchange you'll be free to learn about star maps, astronomy, and the speciality of X-ray astronomy. The first such source in the constellation Andromeda is an astronomical X-ray source detected at some point in human history between now and a distant time mark in the past. It is an astronomical X-ray source detected in the constellation Andromeda.

This learning resource is experimental in nature because each learner interested in seeking this first X-ray source may start with any source and attempt to determine if this source is in Andromeda and is an X-ray source. Each currently known source has a history that includes earlier and earlier detections. To succeed, the adventurer need only show that their source has an earlier detection date as an X-ray source than previous adventurers.

The celestial sphere has coordinate systems often used to place a point source in the heavens. Familiarity with these coordinate systems is not a prerequisite. An introductory geography or map reading course or some familiarity with following a map is all that's needed.

Over the history of X-ray astronomy a number of astronomical X-ray sources have been discovered and studied, usually because they have something special about them that intrigues the researcher. The challenge of this resource is geometrical, astrophysical, and historical. As the ultimate answer is unknown, this is actually a research project, yet you may succeed!

Enjoy learning by doing!

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Selected quiz

Radiation astrochemistry quiz

Main resources: Radiation astronomy/Chemistry/Quiz and Radiation astrochemistry quiz

This is a natural color image of Titan. Credit: NASA/JPL/Space Science Institute.

Radiation chemistry, or astronomical radiation chemistry, is a lecture for the course principles of radiation astronomy about the abundance and reactions of chemical elements and molecules in the universe.

You are free to take this quiz at any time and as many times as you wish to improve your score.

Once you’ve read and studied the lecture, the links contained within, and listed under See also, External links and those in the {{principles of radiation astronomy}} template, you should have adequate background to get 100 %.

Enjoy learning by doing!

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Selected laboratory

Cratering astronomy laboratory

Main resources: Astronomy/Craters/Laboratory and Cratering astronomy laboratory

File:Santa Ana Volcano.USAF.C-130.3-1.jpg

The crater in Santa Ana Volcano is photographed from a United States Air Force C-130 Hercules flying above El Salvador. Credit: José Fernández, U.S Air Force.

This laboratory is an activity for you to create or analyze a cratering. While it is part of the astronomy course principles of radiation astronomy, it is also independent.

Some suggested types of cratering to consider include a lightning strike, a bullet shot into some material, a water droplet hitting the surface of a beaker of water, a subterranean explosion, a sand vortex, or a meteorite impact.

More importantly, there is your cratering idea. And, yes, you can crater a peanut butter and jelly sandwich if you wish to.

Okay, this is an astronomy cratering laboratory, but you may create what a crater is. Another example is a volcanic crater.

I will provide an example of a cratering experiment. 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

Energy phantoms

Main resource: Energy phantoms

This is an optical image in the visual range of Theta Ursae Majoris. It is listed in SIMBAD as an F7V spectral type star with a parallax of 74.19 mas. Credit: Aladin at SIMBAD.

Students start from specific situations of motion, determine how to calculate energy and convert units, then evaluate types of energy.

Def. a quantity that denotes the ability to do work and is measured in a unit dimensioned in mass × distance²/time² (ML²/T²) or the equivalent is called energy.

Def. a physical quantity that denotes ability to push, pull, twist or accelerate a body which is measured in a unit dimensioned in mass × distance/time² (ML/T²): SI: newton (N); CGS: dyne (dyn) is called force.

In astronomy we estimate distances and times when and where possible to obtain forces and energy.

The key values to determine in both force and energy are (L/T²) and (L²/T²). Force (F) x distance (L) = energy (E), L/T² x L = L²/T². Force and energy are related to distance and time using proportionality constants.

Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them:
$F=G{\frac {m_{1}m_{2}}{r^{2}}}\$, where: F is the force between the masses, G is the gravitational constant, m1 is the first mass, m2 is the second mass, and r is the distance between the centers of the masses.	The diagram shows two masses attracting one another. Credit: Dna-Dennis.

In the International System of Units (SI) units, F is measured in newtons (N), m₁ and m₂ in kilograms (kg), r in meters (m), and the constant G is approximately equal to 6.674×10⁻¹¹
 N m² kg⁻².

Observationally, we may not know the origin of the force.

Coulomb's law states that the electrostatic force $F$ experienced by a charge, $q$ at position $r_{q}$, in the vicinity of another charge, $Q$ at position $r_{Q}$, in vacuum is equal to:

$F={qQ \over 4\pi \varepsilon _{0}}{1 \over {r^{2}}},$

where $\varepsilon _{0}$ is the electric constant and $r$ is the distance between the two charges.

Coulomb's constant is

$k_{e}=1/(4\pi \varepsilon _{0}\varepsilon ),$

where the constant $\varepsilon _{0}$ is called the permittivity of free space in SI units of C² m⁻² N⁻¹.

For reality, $\varepsilon$ is the relative (dimensionless) permittivity of the substance in which the charges may exist.

The energy $E$ for this system is

$E=F\cdot D,$

where $D$ is the displacement.

References

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Selected X-ray astronomy pictures

Chandra image of two galaxies (Arp 270) in the early stage of a merger in the constellation Leo Minor. In the image, red represents low, green intermediate, and blue high-energy (temperature) X-rays. Image is 4 arcmin on a side. RA 10^h 49^m 52.5^s Dec Template:Dec. Observation date: April 28, 2001. Instrument: ACIS. Credit: NASA/U. Birmingham/A.Read.

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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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Related portals

Other Wikiversity science-related portals: Anthropology - Archaeology - Astronomy - Biology - Biochemistry - Chemistry - Ecology - Fluid mechanics - Genetics - Hematology - Immunology - Life sciences - Materials science and engineering - Neurology - Organic chemistry - Particle physics - Quantum biology - Regional anatomy - Sciences - Technology

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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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