The dying star that created a cosmic jug

IC 2220, also known as the Toby Jug Nebula, is an extraordinary find in the realm of astronomy. This reflection nebula, situated approximately 1200 light-years away in the constellation Carina, resembles an old English drinking vessel. It derives its illumination from the red-giant star at its center, creating a double-lobed or bipolar cloud of gas and dust.

The Toby Jug Nebula presents a rare opportunity for researchers to delve into the study of stellar evolution, as this phase in the life cycle of red giant stars is relatively fleeting. The celestial structures that emerge around these stars are uncommon, making this nebula an excellent case study.

The captivating image, taken by the Gemini South telescope, showcases the Toby Jug Nebula’s remarkable and nearly symmetrical double-looped structure, as well as its luminous stellar core. These distinct characteristics are exclusive to red giants as they transition from aging stars to planetary nebulae. They provide astronomers with valuable insights into the evolution of low- to intermediate-mass stars approaching the end of their lifespans, as well as the cosmic formations they engender.

At the heart of the Toby Jug Nebula lies its progenitor, the red-giant star HR3126. Red giants form when a star depletes its hydrogen fuel in its core. With no fusion to counterbalance gravitational forces, the star contracts, causing the core temperature to rise and the star to expand up to 400 times its original size.

HR3126 is significantly younger than our sun, being a mere 50 million years old compared to the sun’s age of 4.6 billion years. However, it possesses five times the mass of the sun, enabling it to deplete its hydrogen supply and evolve into a red giant at an accelerated pace.

As HR3126 expanded, its atmosphere swelled, and it began shedding its outer layers. The expelled stellar material dispersed into the surrounding space, giving rise to a magnificent structure of gas and dust that reflects the central star’s light. Infrared studies of the Toby Jug Nebula have revealed that silicon dioxide (silica) is the most likely compound responsible for reflecting HR3126’s light.

Astronomers hypothesize that the bipolar structures akin to those observed in the Toby Jug Nebula result from interactions between the central red giant and a binary companion star. However, previous observations have not detected any such companion to HR3126. Instead, astronomers have observed an exceedingly compact disk of material encircling the central star. This discovery suggests that a former binary companion was potentially torn apart, giving rise to the disk and triggering the formation of the surrounding nebula.

In approximately five billion years, when our sun has exhausted its hydrogen supply, it will undergo a similar transformation into a red giant, ultimately evolving into a planetary nebula. In the distant future, all that will remain of our Solar System will be a vibrant nebula akin to the Toby Jug Nebula, with our cooling sun at its core.

The image of the Toby Jug Nebula was processed by the NOIRLab’s Communication, Education & Engagement team as part of the NOIRLab Legacy Imaging Program. The Gemini South telescope on Cerro Pachón in Chile captured the observations using one of its dual Gemini Multi-Object Spectrographs (GMOS). While spectrographs are primarily designed for studying light at various wavelengths, the GMOS spectrographs also possess powerful imaging capabilities, as exemplified by this exceptional view of the Toby Jug Nebula.

Source: Association of Universities for Research in Astronomy

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