Thursday, 26 June 2025

The Tadpoles aka IC410 in Seestar S30 RGBSHO format.

 

The Tadpoles (centre right) Seestar  S30 (RGB SHO format).
Image credit: Pip Stakkert and Kurt Thrust.

"Mid-summer at the Jodrell Plank Observatory in Lowestoft, the nights are only truly dark for two or three hours, so June is the month, when we maintain our equipment, make new bits of kit and learn new skills. Kurt since returning from holiday, has been busy making a new solar white light filter for the 125mm Meade refractor and designing a transmission grating for the Seestar S30. Pip has been hard at study investigating the use of SIRIL software as a preprocessing first stage in the creation of deepsky images like the one above. In future we shall be using SIRIL to undertake initial stretching of data and the photometric calibration of colour in all our imagery. We hope you all approve!" - Joel Cairo CEO of the Jodrell Plank Observatory.

Widefield view of IC410 and NGC1893
data captured with the Seestar S30 robotic telescope

"Nestled deep in the rich star fields of the constellation Auriga lies a compelling region of stellar birth and evolution known as IC 410, a glowing emission nebula that encapsulates the dynamic story of cosmic creation. This region, set approximately 12,000 light-years from Earth, is more than just a celestial spectacle; it is a living laboratory of astrophysical processes shaped by the energetic lives of massive stars. At the heart of this nebula resides the young open star cluster NGC 1893, whose powerful influence has sculpted the surrounding clouds of gas and dust into mesmerizing structures, including the enigmatic “Tadpoles” of IC 410.

The Nebula IC 410

IC 410 is classified as an emission nebula, a vast cloud of ionized hydrogen gas (H II region) that glows in visible light as it is energized by the ultraviolet radiation of nearby hot stars. The reddish hues that dominate images of IC 410 are primarily due to the H-alpha emissions from excited hydrogen atoms, giving the nebula its distinctive fiery appearance. Extending over roughly 100 light-years, the nebula is part of a larger region of ongoing star formation.

IC 410’s radiance is not uniform. It contains darker dust lanes, filamentary structures, and bright knots—evidence of complex interactions between stellar winds, radiation pressure, and turbulent gas flows. This interplay creates shock fronts and compression zones, setting the stage for future generations of star formation.

Star Cluster NGC 1893

Embedded within IC 410, the open cluster NGC 1893 provides the energy and dynamism that drives much of the nebula’s current activity. Composed of several thousand stars, NGC 1893 is a relatively young cluster, estimated to be around 4 million years old. Among these stars are numerous hot, massive O- and B-type stars whose intense radiation and stellar winds exert a powerful influence on the surrounding interstellar medium.

The feedback from these massive stars—both through radiation pressure and mechanical outflows—has a dual effect. It can erode and disperse the surrounding gas, halting star formation in some areas, while simultaneously compressing other regions, triggering the collapse of gas clouds and the birth of new stars. This process, known as triggered star formation, is believed to play a key role in shaping IC 410’s morphology and fueling its continued evolution.

The Tadpoles of IC 410

Among the most visually and scientifically intriguing features within IC 410 are the structures known as the “Tadpoles.” These are elongated, cometary-shaped clouds of gas and dust that appear to be swimming through the glowing plasma of the nebula. There are two primary Tadpoles, officially designated as Sim 129 and Sim 130, named after astronomer Colin T. Simmons who cataloged them.

Each Tadpole is several light-years in length and has a dense, globule-like head followed by a trailing tail. These features are aligned in a direction that points away from the central cluster, suggesting they have been sculpted by the intense stellar winds and radiation emanating from the hot stars of NGC 1893. The leading edges of the Tadpoles are shielded from the full brunt of the radiation, allowing gas to survive in denser form, while the tails are formed as material is photoevaporated and swept back.

Observations in the infrared and radio wavelengths have revealed signs of star formation occurring within the heads of the Tadpoles. These proto-stellar objects, embedded in dense molecular material, suggest that even in the harsh environment of a bright emission nebula, pockets of gas can remain stable enough to collapse under their own gravity and give rise to new stars.

Formation and Evolutionary Processes

The formation of IC 410 and NGC 1893 likely began as a giant molecular cloud collapsed under gravitational instability, forming the first generation of massive stars that now dominate the cluster. The intense radiation and mechanical energy from these stars initiated a feedback loop that shaped the surrounding gas into arcs, filaments, and pillar-like structures such as the Tadpoles.

The Tadpoles are thought to be remnants of denser clumps of gas that were originally part of the molecular cloud. As the surrounding material was eroded away, these clumps resisted dispersal due to their higher density. Over time, they were shaped by the erosive forces of UV radiation, developing the characteristic head-tail morphology seen today.

Astronomers have used data from telescopes such as Spitzer, Chandra, and Hubble, as well as ground-based observatories, to study IC 410 across multiple wavelengths. X-ray emissions detected by Chandra reveal high-energy processes and young, embedded stars, while infrared observations from Spitzer show warm dust and the earliest stages of stellar formation.

Overview

IC 410, together with the open cluster NGC 1893 and the Tadpoles Sim 129 and Sim 130, represents a dynamic example of the cycle of stellar birth and feedback. The interaction between massive stars and their environment drives both destruction and creation, sculpting the nebula and triggering new generations of stars in a cosmic relay that spans millions of years.

In studying regions like IC 410, astronomers gain crucial insights into the processes that govern star formation across the galaxy. These structures not only illuminate the physics of interstellar matter and radiation, but also echo the early conditions under which our own Sun and solar system may have formed, making IC 410 not just a window into the distant cosmos, but a reflection of our own origins".

 -Professor G.P.T Chat visiting astrophysicist at the Jodrell Plank Observatory

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