The High Resolution Coronal Imager (Hi-C) is a sub-orbital telescope designed to take high-resolution images of the Sun's corona. As of 2020 [update] it has been launched three times, but only the first and the third launches, on July 11, 2012, and May 29, 2018, resulted in a successful mission. [1] It was launched aboard a Black Brant sounding rocket from White Sands Missile Range, New Mexico. [2] The images taken were the highest resolution photos ever of the Sun's corona. [3]
The telescope weighs 464 pounds (210 kg), and is 10 feet (3.0 m) long. [3] The mirrors are approximately 9.5 inches (24 cm) across. Its optics were designed at the Marshall Space Flight Center in Huntsville, Alabama with assistance from the Smithsonian Astrophysical Observatory and L-3Com/Tinsley Laboratories of Richmond, California. Dr. Jonathan Cirtain, from MSFC said: "These mirrors were to be the finest pieces of glass ever fabricated for solar astrophysics." [4]
The imaging system was designed by Apogee Imaging Systems with a resolution of 0.1 arcsec/pixel (14 times higher resolution than the Solar Dynamics Observatory). It was based on a customized version of the E2V CCD203 from Lockheed Martin, which is a very large 4 channel back illuminated 4,000 × 4,000 pixel charge-coupled device (CCD). [2]
The first flight lasted for 10 minutes, reached an altitude of 283 kilometres (176 mi) and the telescope captured 165 images of a large active region. It imaged the Sun in ultraviolet light at 19.3 nm wavelength. [5] The total cost of the mission was $5 million. [6]
On the second flight, in 2018, five and a half minutes (329 seconds) of pictures were taken of an area on the sun 4.4 arcminutes square (the sun's disk being about 30 arcminutes in diameter). Seventy eight images were taken at intervals of 4.4 seconds, with a two-second exposure time, at the extreme ultraviolet wavelength of 17.2 nanometres which is dominated by Fe IX emission (emission from iron in the +8 ionization state) indicating temperatures around 800 000 Kelvin. The instrument was able to resolve strands of plasma as narrow as about 200 kilometres wide.
The first mission revealed never-before-seen "magnetic braids" of plasma roiling in the Sun's outer layers. [3] It was the first time scientists were able to directly observe magnetic reconnection in braids, which may be the primary sources of heating in the active solar corona. [5] [7]
A corona is the outermost layer of a star's atmosphere. It consists of plasma.
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy uses a type of space telescope that can see x-ray radiation which standard optical telescopes, such as the Mauna Kea Observatories, cannot.
The Solar and Heliospheric Observatory (SOHO) is a European Space Agency (ESA) spacecraft built by a European industrial consortium led by Matra Marconi Space that was launched on a Lockheed Martin Atlas IIAS launch vehicle on 2 December 1995, to study the Sun. It has also discovered over 4,000 comets. It began normal operations in May 1996. It is a joint project between the European Space Agency (ESA) and NASA. SOHO was part of the International Solar Terrestrial Physics Program (ISTP). Originally planned as a two-year mission, SOHO continues to operate after over 25 years in space; the mission has been extended until the end of 2025, subject to review and confirmation by ESA's Science Programme Committee.
The Extreme ultraviolet Imaging Telescope (EIT) is an instrument on the SOHO spacecraft used to obtain high-resolution images of the solar corona in the ultraviolet range. The EIT instrument is sensitive to light of four different wavelengths: 17.1, 19.5, 28.4, and 30.4 nm, corresponding to light produced by highly ionized iron (XI)/(X), (XII), (XV), and helium (II), respectively. EIT is built as a single telescope with a quadrant structure to the entrance mirrors: each quadrant reflects a different colour of EUV light, and the wavelength to be observed is selected by a shutter that blocks light from all but the desired quadrant of the main telescope.
Transition Region and Coronal Explorer was a NASA heliophysics and solar observatory designed to investigate the connections between fine-scale magnetic fields and the associated plasma structures on the Sun by providing high resolution images and observation of the solar photosphere, the transition region, and the solar corona. A main focus of the TRACE instrument is the fine structure of coronal loops low in the solar atmosphere. TRACE is the third spacecraft in the Small Explorer program, launched on 2 April 1998, and obtained its last science image on 21 June 2010, at 23:56 UTC.
The Solar Orbiter (SolO) is a Sun-observing probe developed by the European Space Agency (ESA) with a National Aeronautics and Space Administration (NASA) contribution. Solar Orbiter, designed to obtain detailed measurements of the inner heliosphere and the nascent solar wind, will also perform close observations of the polar regions of the Sun which is difficult to do from Earth. These observations are important in investigating how the Sun creates and controls its heliosphere.
International Ultraviolet Explorer, was the first space observatory primarily designed to take ultraviolet (UV) electromagnetic spectrum. The satellite was a collaborative project between NASA, the United Kingdom's Science and Engineering Research Council and the European Space Agency (ESA), formerly European Space Research Organisation (ESRO). The mission was first proposed in early 1964, by a group of scientists in the United Kingdom, and was launched on 26 January 1978 aboard a NASA Thor-Delta 2914 launch vehicle. The mission lifetime was initially set for 3 years, but in the end it lasted 18 years, with the satellite being shut down in 1996. The switch-off occurred for financial reasons, while the telescope was still functioning at near original efficiency.
Solar physics is the branch of astrophysics that specializes in the study of the Sun. It deals with detailed measurements that are possible only for our closest star. It intersects with many disciplines of pure physics, astrophysics, and computer science, including fluid dynamics, plasma physics including magnetohydrodynamics, seismology, particle physics, atomic physics, nuclear physics, stellar evolution, space physics, spectroscopy, radiative transfer, applied optics, signal processing, computer vision, computational physics, stellar physics and solar astronomy.
The Solar Dynamics Observatory (SDO) is a NASA mission which has been observing the Sun since 2010. Launched on 11 February 2010, the observatory is part of the Living With a Star (LWS) program.
A coronal hole is a temporary region of relatively cool, less dense plasma in the solar corona where the Sun's magnetic field extends into interplanetary space as an open field. Compared to the corona's usual closed magnetic field that arches between regions of opposite magnetic polarity, the open magnetic field of a coronal hole allows solar wind to escape into space at a much quicker rate. This results in decreased temperature and density of the plasma at the site of a coronal hole, as well as an increased speed in the average solar wind measured in interplanetary space. If streams of high-speed solar wind from coronal holes encounter the Earth, they can cause major displays of aurorae. Near solar minimum, when activity such as coronal mass ejections is less frequent, such streams are the main cause of geomagnetic storms and associated aurorae.
Hinode, formerly Solar-B, is a Japan Aerospace Exploration Agency Solar mission with United States and United Kingdom collaboration. It is the follow-up to the Yohkoh (Solar-A) mission and it was launched on the final flight of the M-V rocket from Uchinoura Space Center, Japan on 22 September 2006 at 21:36 UTC. Initial orbit was perigee height 280 km, apogee height 686 km, inclination 98.3 degrees. Then the satellite maneuvered to the quasi-circular Sun-synchronous orbit over the day/night terminator, which allows near-continuous observation of the Sun. On 28 October 2006, the probe's instruments captured their first images.
The Extreme Ultraviolet Explorer was a NASA space telescope for ultraviolet astronomy. EUVE was a part of NASA's Explorer spacecraft series. Launched on 7 June 1992. With instruments for ultraviolet (UV) radiation between wavelengths of 7 and 76 nm, the EUVE was the first satellite mission especially for the short-wave ultraviolet range. The satellite compiled an all-sky survey of 801 astronomical targets before being decommissioned on 31 January 2001.
In solar physics, a coronal loop is a well-defined arch-like structure in the Sun's atmosphere made up of relatively dense plasma confined and isolated from the surrounding medium by magnetic flux tubes. Coronal loops begin and end at two footpoints on the photosphere and project into the transition region and lower corona. They typically form and dissipate over periods of seconds to days and may span anywhere from 1 to 1,000 megametres in length.
The Sun Watcher using Active Pixel System Detector and Image Processing (SWAP) telescope is a compact extreme-ultraviolet (EUV) imager on board the PROBA-2 mission. SWAP provides images of the solar corona at a temperature of roughly 1 million degrees. the instrument was built upon the heritage of the Extreme ultraviolet Imaging Telescope (EIT) which monitored the solar corona from the Solar and Heliospheric Observatory from 1996 until after the launch of the Solar Dynamics Observatory in 2010.
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.
A nanoflare is a very small episodic heating event which happens in the corona, the external atmosphere of the Sun.
Supra-arcade downflows (SADs) are sunward-traveling plasma voids that are sometimes observed in the Sun's outer atmosphere, or corona, during solar flares. In solar physics, arcade refers to a bundle of coronal loops, and the prefix supra indicates that the downflows appear above flare arcades. They were first described in 1999 using the Soft X-ray Telescope (SXT) on board the Yohkoh satellite. SADs are byproducts of the magnetic reconnection process that drives solar flares, but their precise cause remains unknown.
The Wide-Field Imager for Solar Probe (WISPR) is an imaging instrument of the Parker Solar Probe mission to the Sun, launched in August 2018. Imaging targets include visible light images of the corona, solar wind, shocks, solar ejecta, etc. Development of WISPR was led by the U.S. Naval Research Laboratory. The Parker Solar Probe with WISPR on board was launched by a Delta IV Heavy on 12 August 2018 from Cape Canaveral, Florida. WISPR is intended take advantage of the spacecraft's proximity to the Sun by taking coronagraph-style images of the solar corona and features like coronal streamers, plumes, and mass ejections. One of the goals is to better understand the structure of the solar corona near the Sun.
Kelly Korreck is an American space scientist. She is currently an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian and Program Scientist at NASA as head of operations for the Solar Wind Electrons Alphas and Protons (SWEAP) instrument aboard the Parker Solar Probe spacecraft.
Daniel B. Seaton is an American solar physicist based at the Southwest Research Institute (SwRI) in Boulder, Colorado. He is particularly known for his work on producing and interpreting images of the solar corona, using both visible light and extreme ultraviolet.