More than a century after a spectacular stellar explosion lit up the night time sky above the constellation Perseus, NASA’s latest house telescope, SPHEREx, has uncovered one thing nobody anticipated: The historic nova GK Persei is surrounded by a beforehand unknown envelope of molecular hydrogen, probably the most ample molecule within the universe, stretching roughly 8-by-5 light-years throughout.
The study, led by Professor D. P. Ok. Banerjee of the Physical Research Laboratory in Ahmedabad, India, in collaboration with a world staff together with Arizona State University Regents Professor Sumner Starrfield of the School of Earth and Space Exploration, additionally consists of researchers from the United States, the United Kingdom and Estonia. The findings printed in The Astrophysical Journal Letters characterize an essential new chapter within the historical past of considered one of astronomy’s most iconic objects, providing new clues about the evolution of classical novae.
“The eruption occurred 125 years ago, yet it continues to reveal new phenomena that surprise us,” Starrfield stated. “We are trying to understand how the nova outburst is interacting with the nebula and the H2 molecular envelope.”
A stellar explosion that keeps surprising astronomers
Nova Persei 1901, known to astronomers as GK Persei, was the first bright classical nova of the 20th century. In these events, a dense white dwarf star pulls gas from a companion star until a surface explosion makes the system about a million times brighter for a short time, before it dims again.
GK Persei’s 1901 eruption was dramatic. Within months, astronomers observed ghostly light echoes racing outward at apparent speeds faster than light: an optical illusion caused by the explosion’s flash illuminating surrounding clouds of gas and dust. The shell of debris from the explosion is still visible today and spans about 1 light-year.
Around this small remnant is a much bigger structure: a bipolar, two-lobed nebula about 8 light-years wide. Its origin has puzzled astronomers for years. Some thought it was an old planetary nebula from an earlier stage of the star’s life, while others were not convinced.
“GK Persei keeps holding major surprises,” Banerjee said. “The eruption occurred 125 years ago, yet it continues to reveal new phenomena that challenge our understanding. In this study, we have tried to explain the nova outburst, the nebula and the H2 molecular envelope in a unified way.”
SPHEREx: A new kind of cosmic detective
NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) is designed to survey the entire sky in infrared light with unprecedented sensitivity. Molecular hydrogen, which is normally invisible to conventional optical telescopes, emits faint infrared signatures that SPHEREx is uniquely equipped to detect.
The new observations show that molecular hydrogen traces the full extent of the bipolar nebula surrounding GK Persei, suggesting that the two structures are directly connected — a significant clue in a cold case that has been open for over a century.
“It is really exciting to see the ways the science community, both around the world and on campus here at ASU, is using SPHEREx data to answer new science questions,” stated Sean Bryan, ASU School of Earth and Space Exploration affiliate analysis professor, survey lead for the SPHEREx mission and member of the science staff.
ASU’s function in NASA mission science
The School of Earth and Space Exploration at ASU maintains robust connections to NASA mission science, with college conducting analysis in areas reminiscent of stellar astrophysics, infrared spectroscopy and interstellar chemistry. Discoveries such because the huge envelope of molecular hydrogen round GK Persei spotlight ASU’s ongoing dedication to advancing our understanding of the universe’s origins and evolution.
Images of the GK Persei nebula from Deep Sky Collective, taken over greater than 265 hours, give further visible context for the SPHEREx findings. These photographs present that the molecular hydrogen is linked to the supposed planetary nebula construction.
“The numbers just do not add up for the large nebula to be a recent event,” Starrfield stated. “A typical planetary nebula lives for only about 30,000 years and would be long gone by the time the white dwarf had faded to its current brightness, which takes about a million years.”
Why it issues
Classical novae are among the many most energetic and chemically productive occasions within the galaxy. Understanding how their remnants evolve and what molecular species survive and kind of their aftermath has direct implications for fashions of stellar evolution, the chemical enrichment of the interstellar medium and the life cycle of stars.
With SPHEREx scanning the entire sky within the infrared, astronomers suppose GK Persei is barely the primary of many stellar remnants that can present options that we can’t see with optical telescopes. It appears the universe retains its secrets and techniques for a very long time, however new house telescopes are lastly beginning to uncover them.
Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) is a joint mission of the Jet Propulsion Laboratory and the California Institute of Technology, and is funded by the National Aeronautics and Space Administration.