astronomy

Interface Region Imaging Spectrograph

Interface Region Imaging Spectrograph is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Interface Region Imaging Spectrograph rather than just read about it. In short: Interface Region Imaging Spectrograph (IRIS), also called Explorer 94 and SMEX-12, is a NASA solar observation satellite. The mission was funded through the Small Explorer program to investigate the physical conditions of the solar limb, particularly the interface region made up of the chromosphere and transition region.

Key takeaways

Interface Region Imaging Spectrograph belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Interface Region Imaging Spectrograph to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Interface Region Imaging Spectrograph from memory before moving on to harder problems.

Reference excerpt

Interface Region Imaging Spectrograph (IRIS), also called Explorer 94 and SMEX-12, is a NASA solar observation satellite. The mission was funded through the Small Explorer program to investigate the physical conditions of the solar limb, particularly the interface region made up of the chromosphere and transition region. The spacecraft consists of a satellite bus and spectrometer built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), and a telescope provided by the Smithsonian Astrophysical Observatory (SAO). IRIS is operated by LMSAL and NASA's Ames Research Center. The satellite's instrument is a high-frame-rate ultraviolet imaging spectrometer, providing one image per second at 0.3-arcsecond angular resolution and sub-ångström spectral resolution. NASA announced, on 19 June 2009, that IRIS was selected from six Small Explorer mission candidates for further study, along with the Gravity and Extreme Magnetism (GEMS) space observatory.

Mission IRIS is intended to advance Sun-Earth connection studies by tracing the flow of energy and plasma into the corona and heliosphere for which no suitable observations exist. To achieve this IRIS obtains a high-resolution UV spectra and images of the Sun's chromosphere, specifically on the non-thermal energy that creates the corona and the solar wind. IRIS seeks to determine: (1) the types of non-thermal energy which dominate in the chromosphere and beyond; (2) the means by which the chromosphere regulates mass and energy supply to the corona and heliosphere; and, (3) how magnetic flux and matter rise through the lower solar atmosphere, and the role played by flux emergence in flares and mass ejections. To answer these questions, IRIS utilize a single instrument, a multi-channel imaging spectrograph.

Launch The spacecraft arrived at Vandenberg Air Force Base, California, on 16 April 2013 and was successfully deployed from an Orbital L-1011 carrier aircraft flying over the Pacific Ocean at an altitude of 12,000 m (39,000 ft), roughly 160 km (99 mi) northwest of Vandenberg. The launch vehicle was dropped at 02:27:46 UTC on 28 June 2013 (7:27 p.m. PDT on 27 June 2013) by a Pegasus-XL launch vehicle.

Experiment

Interface Region Imaging Spectrograph (IRIS) The IRIS instrument is a multi-channel imaging spectrograph with a 19 cm (7.5 in) ultraviolet telescope. IRIS obtains a spectra along a slit (1/3 arcsecond wide), and slit-jaw images. The charge-coupled device (CCD) detectors has 1/6 arcsecond pixels. IRIS will have an effective spatial resolution between 0.33 and 0.40 arcsecond and a maximum field of view (FoV) of 120 arcseconds. The far-ultraviolet channel covers 133.2-135.8 nm and 139.0-140.6 nm with an 0.04 nm resolution and an effective area of 2.8 cm2 (0.43 sq in). The near-ultraviolet channel covers 278.5-283.5 nm with an 0.08 nm resolution and an effective area of 0.3 cm2 (0.047 sq in). Slit-jaw imaging has four passbands: 133.5 nm and 140.0 nm with a 4 nm bandpass each; and 279.6 nm and 283.1 nm with a 0.4 nm bandpass each. IRIS has a high data rate (0.7 Mbit/s on average) so that the baseline cadence is 5 seconds for slit-jaw images and 1 second for six spectral windows, including rapid rastering to map solar regions.

Science results IRIS achieved first light on 17 July 2013. NASA noted that "IRIS's first images showed a multitude of thin, fibril-like structures that have never been seen before, revealing enormous contrasts in density and temperature occur throughout this region even between neighboring loops that are only a few hundred miles apart". On 31 October 2013, calibrated IRIS data and images were released on the project website. An open-access article describing the satellite and initial data was published in the journal Solar Physics. Data collected from the IRIS spacecraft has shown that the interface region of the Sun is significantly more complex than previously thought. This includes features described as solar heat bombs, high-speed plasma jets, nano-flares, and mini-tornadoes. These features are an important step in understanding the transfer of heat to the corona. In 2019, IRIS detected tadpole like jets coming out from the Sun according to NASA.

IRIS team Science and engineering team members include:

Lockheed Martin Solar and Astrophysics Laboratory Lockheed Martin Sensing and Exploration Systems Smithsonian Astrophysical Observatory Montana State University Institute for Theoretical Astrophysics, University of Oslo High Altitude Observatory, National Center for Atmospheric Research Stanford University NASA Ames Research Center NASA Goddard Space Flight Center National Solar Observatory Space Sciences Laboratory, University of California, Berkeley Princeton Plasma Physics Laboratory Sydney Institute for Astronomy, University of Sydney Center for Plasma Astrophysics, Catholic University of Leuven Mullard Space Science Laboratory Rutherford Appleton Laboratory European Space Agency Max Planck Institute for Solar System Research National Astronomical Observatory of Japan Niels Bohr Institute, University of Copenhagen

References

External links

Official website at NASA Science Official website at NASA Goddard Space Flight Center Official website at Lockheed Martin Solar and Astrophysics Laboratory De Pontieu, B., Polito, V., Hansteen, V. et al. A New View of the Solar Interface Region from the Interface Region Imaging Spectrograph (IRIS) Sol Phys 296, 84 (2021) https://doi.org/10.1007/s11207-021-01826-0

Illustrations

Worked examples

Example 1 — a first encounter with Interface Region Imaging Spectrograph

Start with the simplest possible case. Write down what Interface Region Imaging Spectrograph claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Interface Region Imaging Spectrograph before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Interface Region Imaging Spectrograph ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Interface Region Imaging Spectrograph

In research: Interface Region Imaging Spectrograph appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Interface Region Imaging Spectrograph in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Interface Region Imaging Spectrograph is common in secondary-school and first-year university syllabi. It links to neighbouring topics Explorers Program, Lockheed Martin satellites, Missions to the Sun, so understanding it makes those chapters shorter.
In everyday life: Look for Interface Region Imaging Spectrograph outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Interface Region Imaging Spectrograph in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Interface Region Imaging Spectrograph means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Interface Region Imaging Spectrograph out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Interface Region Imaging Spectrograph in simple terms?

Why does Interface Region Imaging Spectrograph matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Interface Region Imaging Spectrograph?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Interface Region Imaging Spectrograph.