The Center for Astrophysics | Harvard & Smithsonian

The Center for Astrophysics | Harvard & Smithsonian

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Srijan Bharati Das

Center for Astrophysics

Astrophysicist (Post-Doctoral Research Fellow)

Srijan Bharati Das

sbdas@cfa.harvard.edu

About

Srijan's research is often at the intersection of plasma physics, MHD and inverse theory/optimization. At CfA, Srijan focuses on understanding the nature of switchbacks observed by Parker Solar Probe (PSP), optimizing velocity distribution functions (VDFs) from joint measurements of SPAN and SPC instruments onboard PSP and evaluating the fidelity of photospheric vs. chromospheric magnetic field extrapolations using PFSS models. While his research is focused on the solar space environment at CfA, he continues to remain active in helioseismology and asteroseismology (the focus of his PhD and Marie-Curie Postdoctoral Fellowship at IST-Austria) to probe magnetic fields in the solar and stellar interiors.

BS-MS IISER-Kolkata, PhD Princeton University

Telescopes and Instruments

Kepler/K2

Since the early 1990s, astronomers have identified thousands of planets orbiting other stars. Most of those identifications have come thanks to one observatory: NASA’s Kepler space telescope. Until it lost its ability to point, Kepler observed a region of the sky containing about 150,000 stars with potential planets, monitoring them for the slight decrease in light caused by planets crossing in front of the star. After the spacecraft’s pointing control failed, the mission was renamed K2, and it continued to hunt for exoplanets as it tumbled slowly, with its field of view drifting slowly across the sky. The mission finally ended in 2018, though the data it produced continues to provide astronomers with valuable information about planets in our galactic neighborhood. Astronomers from the Center for Astrophysics | Harvard & Smithsonian were responsible for the preparation of the catalog for potentially interesting stars, and have participated extensively in follow-up observations of Kepler planetary discoveries.

Visit the Kepler/K2 Website

Solar Dynamics Observatory (SDO)

The Sun is both life-giving and dangerous. Variations in the Sun’s light and wind have profound effects on Earth, while solar storms can wreak havoc on power and communications systems. NASA’s Solar Dynamics Observatory (SDO) is a spacecraft dedicated to studying these potentially dangerous variations, and the magnetic fields that drive them. Engineers at the Center for Astrophysics | Harvard & Smithsonian contributed to the design and construction of the four Atmospheric Imaging Array (AIA) telescopes. AIA is one of the three major experiments carried by SDO.

Visit the SDO Website

Parker Solar Probe

What is driving the solar wind? Some particles in the Sun’s atmosphere gain enough speed to escape the Sun’s gravitational pull and bombard the worlds of the Solar System, but the processes behind the phenomenon are still mysterious. To solve that mystery, NASA’s Parker Solar Probe spacecraft was built to fly through the Sun’s atmosphere, performing the first up-close solar measurements in history. Scientists and engineers at the Center for Astrophysics | Harvard & Smithsonian built the Solar Probe Cup (SPC) instrument for the spacecraft. SPC is part of the Solar Wind Electrons Alphas and Protons (SWEAP) instrument suite used to sample particles directly from the Sun’s atmosphere for analysis.

Visit the Parker Solar Probe SWEAP Website

Wind Spacecraft

NASA’s Wind Spacecraft has observed the Sun ever since its launch in 1994, making it one of the most successful and longest-running space observatories. Orbiting at a special location between Earth and the Sun, Wind measures the properties of the electrically-charged particles known as the solar wind. Scientists from the Center for Astrophysics | Harvard & Smithsonian currently operate one of Wind’s instruments, which collects ions from the solar wind. Data from the spacecraft have been used in over 4,500 journal articles, doctoral dissertations, and other scientific publications. Wind was built to last: it has enough fuel to keep operating for another 50 years.

Visit the Wind Spacecraft 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