The Center for Astrophysics | Harvard & Smithsonian

The Center for Astrophysics | Harvard & Smithsonian

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Paola Testa

Center for Astrophysics

Astrophysicist

Paola Testa

ptesta@cfa.harvard.edu

About

I received my doctorate in Physics at the University of Palermo (Italy) on the topic of coronal activity in the Sun and other stars. After my graduate studies I held a post-doctoral appointment at the Kavli Institute for Astrophysics at MIT. My research focuses on understanding the heating mechanisms and X-ray emission processes in the hot outer layers of the atmosphere of the Sun and other stars, by combining observations with advanced numerical modeling. My interests encompass a wide range of astrophysical sources including the Sun, late-type main/pre-main sequence, and early-type stars. I am also involved in development and operations of space instrumentation, as co-I or instrument team member of several missions and of rocket experiments, including the Interface Region Imaging Spectrograph (IRIS), the Hinode X-ray Telescope (XRT), the SDO Atmospheric Imaging Assembly (AIA), the Marshall Grazing Incidence X-ray Spectrometer (MaGIXS), and the Hi-resolution Coronal Imager (Hi-C).

Telescopes and Instruments

High Resolution Coronal Imager (Hi-C)

Why the Sun’s corona — the wispy outermost atmosphere — is so much hotter than its surface stands as a big mystery in solar science. NASA’s High-Resolution Coronal Imager (Hi-C) is an ultraviolet telescope designed to help solve the mystery, and understand the processes by which the Sun sends violent storms of particles into the Solar System. Since most of the light from the Sun’s atmosphere is blocked by air molecules on Earth, Hi-C is carried on a short-flight rocket into Earth’s upper atmosphere. Since 2012, Hi-C has flown three times, providing the highest resolution images of the corona and revealing new details in the Sun’s atmosphere. Hi-C is jointly operated by NASA's Marshall Space Flight Center (MSFC) and the Center for Astrophysics | Harvard & Smithsonian, with contributions from other researchers around the world.

Visit the Hi-C Website

Solar and Heliospheric Observer (SOHO)

The Sun is the only star we can study in detail, providing us with the opportunity to observe stellar internal structure, magnetic fields, and atmosphere. Solar and Heliospheric Observer (SOHO), a space observatory jointly operated by NASA and the European Space Agency (ESA), has been one of the best sources for that knowledge. Originally designed to operate for two years, SOHO has provided daily data on the Sun for more than twenty years, making it one of the longest running space observatories. During that time, SOHO has monitored the Sun’s atmosphere, surface, and seismology, using a wide range of scientific instruments. Scientists and engineers at the Center for Astrophysics | Harvard & Smithsonian developed the instrument SOHO uses to measure the ultraviolet spectrum of the Sun.

Visit the SOHO/UVCS Website

Transition Region and Coronal Explorer (TRACE)

The Transition Region and Coronal Explorer (TRACE) was a space-based solar observatory which operated from 1998 through 2010. TRACE primarily observed in ultraviolet light to map the small-scale structure of the eruptions of gas on the Sun’s surface known as coronal loops, as well as the “transition region” where the Sun’s atmosphere increases in temperature dramatically. The telescope was a joint project of the Center for Astrophysics | Harvard & Smithsonian, NASA, and Lockheed Martin. The long duration of the mission enabled TRACE to be the second space-based solar observatory to monitor an entire sunspot cycle, which provided valuable information on how the Sun’s magnetic field affects its atmosphere.

Chandra

The Chandra X-ray Observatory is NASA’s flagship X-ray observatory, providing essential data on everything from the environment surrounding newborn stars to the emissions from hot plasma inside galaxy clusters. The Smithsonian Astrophysical Observatory (SAO), as part of the Center for Astrophysics | Harvard & Smithsonian, manages Chandra’s day-to-day operations, providing spacecraft control, observation planning, and data processing for astronomers. Chandra is one of NASA’s orbiting Great Observatories, along with the Hubble.

Visit the Chandra Website

Hinode

The Sun is the closest star to Earth, and the single most important influence on the worlds of the Solar System in terms of the light and particles it emits. Studying the Sun, in other words, helps us understand the habitability of Earth, but also other stars elsewhere in the universe. One important solar observatory is the Japanese Aerospace Exploration Agency’s Hinode spacecraft, which carries three powerful instruments to study the Sun in X-rays, visible light, and ultraviolet light. Center for Astrophysics | Harvard & Smithsonian engineers collaborated in the development of the X-ray Telescope for the spacecraft. Hinode has been observing the Sun continuously since its launch in 2006, providing important day-by-day information about our host star’s activity.

Visit the Hinode/XRT Website

Interface Region Imaging Spectrograph (IRIS)

The Sun’s surface is incandescently hot, but its outer atmosphere — the corona — is far hotter, for reasons astronomers don’t fully understand. NASA’s Interface Region Imaging Spectrograph (IRIS) is an orbiting observatory designed to study the mysterious transitional part of the Sun’s lower atmosphere, where the heating of the material flowing into the corona takes place. Understanding the heating process may help predict solar storms as well. Scientists and engineers from the Center for Astrophysics | Harvard & Smithsonian contributed to the telescope for IRIS. In addition, CfA researchers participate in telescope operations, and provide scientific support and analysis for the observatory’s work.

Visit the IRIS Website