Messier 51 and NGC 5195 revisited with the COAST robotic telescope.

 

Interacting Galaxies M51(NGC 5194) and NGC 5195
- Data Credit:telescope.org, Open Observatories, Open University.
Image Credit: Kurt Thrust at the JPO. 

"With time on his hands, Kurt Thrust found data captured from Tenerife with the COAST robotic telescope and BVR filters in 2024. He worked on the data to emphasise the bright spiral arms in Messier 51 where star formation is evident". - Joel Cairo CEO of the Jodrell Plank Observatory.

Tidal Encounters and Star Formation in the M51 System: A Case Study of NGC 5194 and NGC 5195

A high-resolution optical image of the M51 system. NGC 5194 (left) displays grand-design spiral arms that wrap around the smaller, lenticular companion NGC 5195 (right). This iconic view shows the tidal bridge of stars and gas connecting the two galaxies—a clear signature of their ongoing gravitational interaction.

                    Optical Image of the M51 System (NGC 5194 and NGC 5195)

Source: Hubble Space Telescope / NASA, ESA

Authors: Professor G.P.T Chat, visiting astrophysicist at the Jodrell Plank Observatory and Kurt Thrust current Director of the Jodrell Plank Observatory.

The M51 system, composed of the grand-design spiral galaxy NGC 5194 and its smaller companion NGC 5195, represents one of the most well-studied examples of galaxy interaction in the nearby universe. Their ongoing gravitational interaction provides a compelling laboratory for investigating the dynamical processes that drive morphological transformations and star formation. In this report, we examine the tidal influence of NGC 5194 on NGC 5195 and explore the implications of their interaction on recent star formation activity within the system, particularly focusing on the peculiar case of NGC 5195, which exhibits signs of both past and suppressed star formation.

1. Introduction

Interacting galaxies provide critical insights into the dynamical evolution of galactic systems. The Whirlpool Galaxy (M51), comprising the spiral galaxy NGC 5194 and its lenticular companion NGC 5195, lies approximately 23 million light-years away in the constellation Canes Venatici. This pair is a prototypical example of a tidal encounter between a massive spiral and a smaller companion. The interaction, first modeled numerically by Toomre & Toomre (1972), is responsible for M51’s prominent spiral structure and continues to be a benchmark for simulations of galaxy interactions.

2. Gravitational Interaction Dynamics

NGC 5195 is currently located just beyond the plane of NGC 5194 and is moving away after a recent close passage through the disk of the larger spiral. This gravitational encounter has triggered large-scale tidal perturbations in both galaxies. The most conspicuous result of this interaction is the grand-design spiral arms of NGC 5194, which have been amplified and maintained by the torque induced by NGC 5195’s gravitational pull.

Simulations and observations suggest that NGC 5195 passed through the disk of NGC 5194 roughly 100–300 million years ago. This close passage induced strong tidal forces, generating density waves in the disk of NGC 5194, enhancing gas compression and leading to significant episodes of star formation. Tidal bridges and tails, seen in H I and optical imaging, confirm this interaction and show material being exchanged between the galaxies.

3. Star Formation in NGC 5195

While NGC 5194 exhibits intense star-forming regions along its spiral arms, NGC 5195 presents a more complex and nuanced case. Classified as an SB0-type lenticular galaxy, NGC 5195 possesses limited cold gas reserves and lacks the large-scale disk structure typically conducive to starburst activity. However, recent multiwavelength observations (e.g., Hubble Space Telescope, Spitzer, and Chandra) have revealed signs of localized star formation and nuclear activity, suggesting the interaction has not been entirely passive for the companion.

                                   Multiwavelength View of Star Formation in the M51 System

Data: Hubble (optical), Spitzer (IR), GALEX (UV), and Chandra (X-ray). Composite credit: NASA / ESA / JPL-Caltech / CXC

Notably, UV and H α imaging reveal faint emission in the central and circumnuclear regions of NGC 5195, indicative of recent, though limited, star formation. The triggering mechanism is likely tidal compression from the interaction, which funneled residual gas into the inner regions. Despite this, the overall star formation rate (SFR) in NGC 5195 remains significantly lower than that of NGC 5194, suggesting either a depletion of star-forming gas or the presence of feedback mechanisms (e.g., AGN activity or supernova-driven outflows) inhibiting widespread star formation.

4. Gas Dynamics and Feedback Processes

CO and H I mapping have shown that while some interstellar medium (ISM) exists in NGC 5195, it is largely confined to its central regions. The lack of extensive molecular gas may explain the subdued star formation. Furthermore, X-ray observations reveal hot gas bubbles and shock-heated regions, implying that energy injection from past starburst episodes or AGN feedback could have disrupted the ISM, suppressing further star formation.

The interface region between NGC 5194 and NGC 5195 shows tidal tails and ionized gas streams, suggesting that the gravitational encounter has facilitated gas exchange. Whether this material will reignite star formation in NGC 5195 remains an open question, dependent on future accretion and cooling timescales.

5. Conclusion

The M51 system exemplifies how tidal interactions shape galaxy morphology and star formation. While NGC 5194 responds to the interaction with a classic spiral arm starburst, NGC 5195 shows only limited, localized star formation, constrained by morphological type, gas availability, and possible feedback mechanisms. The gravitational dance of these two galaxies continues to sculpt their evolution, offering astronomers a vivid example of the complex interplay between dynamics and star formation in interacting systems.

References:

Toomre, A., & Toomre, J. (1972). Galactic Bridges and Tails. ApJ, 178, 623.

Smith, B. J., et al. (2010). Triggered Star Formation in Interacting Galaxies. AJ, 139(3), 1212.

Dumas, G., et al. (2011). Gas Kinematics and Feedback in M51’s Companion. A&A, 528, A10.

Mentuch Cooper, E., et al. (2012). Star Formation in Interacting Galaxies. MNRAS, 419(2), 1409.

Messiers: 99 and 83, Spiral Galaxies

 

Messier 99 - PIRATE robotic telescope, Tenerife, BVR filters
- data  credit: telescope.org, Open Observatories, Open University.
Image credit: Pip Stakkert - Jodrell Plank Observatory.

Messier 83 - PIRATE robotic telescope, Tenerife, BVR filters
- data  credit: telescope.org, Open Observatories, Open University.
Image credit: Kurt Thrust - Jodrell Plank Observatory.

" On recent nights the weather in Lowestoft has prevented any astro-data collection. This is a great pity as the team was enthusiastic about using our Seestar S30 to capture 60 second light subs for the first time. We purchased the Seestar just under a year ago and in that time ZWO, the robotic scopes manufacturer, has upgraded the software app and firmware for free, to enable use on an EQ mount, mosaic mode and now extended subs. The Seestar S30 is excellent value for money!

As we have been unable to capture our own photons, we have been relying on the Open Observatories robotic telescope, PIRATE, to provide them for us. We have just programmed it to take some images of the galaxy NGC 7331 where there has been a recent supernova". - Joel Cairo CEO the Jodrell Plank Observatory.

Galactic Twins Across the Cosmos: A Comparative Look at Spiral Galaxies M99 and M83

By Professor G.P.T. Chat, for the Jodrell Plank Observatory Blog

In the vast tapestry of the universe, spiral galaxies unfurl like celestial pinwheels, each with a unique character shaped by millions—sometimes billions—of years of cosmic evolution. Among these stellar masterpieces, Messier 99 (M99) and Messier 83 (M83) stand out not only for their striking beauty but also for the scientific insight they offer into the life cycle and structure of spiral galaxies. Though separated by millions of light-years, these two galaxies reveal a tale of similarity and contrast, hinting at the forces that sculpt the universe.

The Galactic Players: M99 and M83

M99, located in the constellation Coma Berenices about 50 million light-years from Earth, is a prime example of a grand design spiral galaxy. It is classified as SA(s)c, indicating a loosely wound spiral structure with well-defined arms. Discovered in 1781 by Pierre Méchain, M99 forms part of the Virgo Cluster, a bustling galactic metropolis where interactions are frequent and often dramatic.

In contrast, M83—often referred to as the "Southern Pinwheel"—resides a mere 15 million light-years away in the constellation Hydra. It is categorized as SAB(s)c, suggesting a weak central bar and open spiral arms. Unlike M99, M83 sits on the outskirts of the Centaurus A/M83 Group, a smaller galactic neighborhood. Despite its relative isolation, M83 is anything but quiet.

Structure and Symmetry

Visually, both galaxies exhibit a stunning spiral symmetry, yet their internal structures tell different stories. M99’s arms are elegant but asymmetrical—a clue to its recent turbulent past. Astronomers believe that M99’s lopsided appearance is due to gravitational interactions, likely with nearby galaxies or the intracluster medium of the Virgo Cluster. These interactions may have sparked bursts of star formation and slightly distorted the galaxy’s spiral arms, giving M99 a distinctive "tilted" visage.

M83, on the other hand, shows near-perfect symmetry with six prominent spiral arms radiating from its central bar. Its arms are dust-rich and laced with regions of intense star formation—evident in ultraviolet and H-alpha imaging. The presence of a central bar hints at internal dynamics that funnel gas inward, fueling both starbursts and the possible growth of a central black hole. M83’s smooth, organized spiral structure contrasts with M99’s more chaotic appearance, pointing to a relatively undisturbed evolutionary path.

Starbirth and Stellar Populations

Both M99 and M83 are prolific stellar nurseries, but the scale and intensity of their star formation vary. M99’s star-forming activity is concentrated in its spiral arms and outer disk. Its location within a cluster and the presence of hydrogen gas suggest ongoing accretion and interaction-induced starbursts.

M83, however, is in a league of its own. It is one of the closest and most studied starburst galaxies. Its central region is a hotbed of star formation, with hundreds of young clusters and supernova remnants dotting its inner spiral arms. Since 1923, astronomers have recorded at least six supernovae in M83—an unusually high number that underscores its vigorous star-forming processes.

Infrared and X-ray observations have also revealed a dense, turbulent core where massive stars are born and die in rapid succession. M83’s central starburst activity contrasts sharply with M99’s more evenly distributed stellar generation, offering a compelling case for how environment and internal dynamics shape galactic evolution.

Galactic Narratives

In many ways, M99 and M83 offer a comparative window into two archetypes of spiral galaxies—one shaped by external pressures, the other by internal dynamism.

M99’s story is one of interaction and adaptation. Nestled within the Virgo Cluster, it is subject to tidal forces and intergalactic encounters. These interactions, while disruptive, also stimulate growth and transformation. Its asymmetry and off-center star formation reflect a galaxy in flux—a portrait of evolution in motion.

M83, in contrast, illustrates what happens when a spiral galaxy is largely left to its own devices. With fewer gravitational disruptions, M83 has had the opportunity to develop a strong internal structure and maintain a stable star-forming regime. Its intense central starburst activity, fueled by its bar, speaks to an inward-focused evolution—driven not by external collisions, but by a well-regulated internal engine.

Conclusion

Though they are separated by tens of millions of light-years and shaped by different cosmic environments, M99 and M83 both exemplify the richness and diversity of spiral galaxies. Their comparative analysis allows astronomers to decode the influence of environment, structure, and internal dynamics on galactic evolution.

In the grand chronicle of the universe, galaxies like M99 and M83 are more than just distant pinwheels of stars—they are dynamic ecosystems, each with a history written in gas, dust, and light. By studying them side by side, we begin to unravel the universal threads that bind all spiral galaxies, including our own Milky Way, to the cosmic story.

References

NASA/IPAC Extragalactic Database (NED)

Hubble Space Telescope Imaging Archives

Chandra X-ray Observatory

de Vaucouleurs, G. et al., The Third Reference Catalogue of Bright Galaxies

The Great Globular Star Cluster in the constellation Hercules

 

Two views of the Globular Star Cluster M13.
On the left: a widefield combination of data from our Seestar S30 in Suffolk and the PIRATE robotic telescope on Teneriffe. On the right: an enlarged view of the cluster captured with the PIRATE robotic telescope. Data credits: telescope org, Open Observatories, Open University and the Jodrell Plank Observatory. Image credit: Kurt Thrust.

"The Great Globular Star Cluster, M13, in the constellation Hercules is one of the Northern Hemisphere's 'show stopping' astronomical sights. It can be seen in binoculars from a dark site and is aa go to target for the Jodrell Planks 80x11mm tripod mounted binoculars" - Joel Cairo CEO of the Jodrell Plank Observatory.

Messier 13 in all its glory. Data credit: PIRATE robotic telescope Mount Teide, Teneriffe. Image credit: Pip Stakkert at the JPO.

"What is M13?

Messier 13 is a globular star cluster, which is essentially a spherical collection of hundreds of thousands of stars, all gravitationally bound together and orbiting the halo of our galaxy. It's one of the brightest and best-known globular clusters visible from the Northern Hemisphere, located about 22,200 light-years from Earth in the constellation Hercules.

Stellar Composition and Evolution

Globular clusters like M13 are ancient—roughly 11.65 billion years old, formed not long after the Big Bang. This means almost all the stars within M13 are Population II stars—old, metal-poor, and long-lived.

Most of these stars are low-mass, mainly around 0.8 solar masses, since more massive stars have already evolved off the main sequence. The more massive ones that once existed would have become white dwarfs, neutron stars, or possibly black holes by now.

You can see this reflected in M13’s Hertzsprung-Russell (H-R) diagram: the main sequence ends fairly early, and there’s a prominent red giant branch, with stars in post-main-sequence stages of evolution. Many of these stars are currently in the helium-burning phase, having already exhausted hydrogen in their cores.

Structure and Dynamics

M13 is about 145 light-years in diameter and contains around 300,000 stars. The cluster has a high stellar density, especially toward its core. In the center, stars are separated by just 0.1 light-years or less, compared to around 4 light-years between stars in our solar neighborhood.

Despite this density, stars rarely collide directly due to their small sizes relative to the vast distances between them. However, gravitational interactions are frequent and important. These close encounters can:

Cause mass segregation: heavier stars sink toward the core, while lighter ones migrate outward.

Create binary systems or disrupt existing ones.

Lead to blue straggler stars—stars that appear younger and hotter, likely formed via stellar mergers or mass transfer in binary systems.

Pip Stakkert asked Copilot AI to create a night view of M13 as seen from a rocky airless planet orbiting a star within the Globular cluster. If the star was located towards the the centre of M13 the sky would be awash with light from  thousands of stars and as bright as day.

Orbital Mechanics and Galactic Role

M13 orbits the Milky Way’s galactic center in a roughly elliptical path. Its motion is governed by the galaxy’s gravitational potential. As it orbits, it experiences tidal forces from the Milky Way, which can strip stars from the outer regions—a process called tidal stripping.

Over billions of years, some stars are pulled into tidal streams that trail behind the cluster. These streams are important to astronomers because they help trace the mass distribution and dark matter content of the Milky Way.

Metallicity and Formation Clues

M13 has a metallicity ([Fe/H]) of about –1.5, meaning its stars contain only about 1/30th the iron content of the Sun. This tells us they formed at a time when the universe hadn’t yet produced much heavy element enrichment via supernovae.

Interestingly, while globular clusters were once thought to be composed of stars with a single age and composition, we now know that clusters like M13 show evidence of multiple stellar populations. This means they might have gone through more complex formation histories than originally believed, possibly involving early bursts of star formation or enrichment from earlier generations of stars.

Why Is M13 Special?

Besides being one of the brightest globular clusters, M13 has served as a kind of cosmic message board. In 1974, astronomers sent the Arecibo message toward M13—an interstellar radio message designed to demonstrate human technological achievement. Of course, M13 will have moved by the time the message arrives in 25,000 years, but the symbolism still stands.

Final Thoughts

M13 is a stunning example of gravitational physics in action. It's a self-contained stellar ecosystem where stars evolve, interact, and sometimes collide. Its dynamics help us understand everything from stellar evolution and galactic structure to the early conditions of the universe.

Despite its beauty, M13 is a harsh environment—dense, old, and metallically poor. Yet, within that ancient crucible, the dance of gravity continues, slowly shaping the fates of hundreds of thousands of stars across billions of years". - Professor G.P.T Chat visiting astrophysicist at the Jodrell Plank Observatory

Messier 20- The Trifid Nebula

 

Messier 20 data credit: PIRATE robotic telescope, Teneriffe.
telescope.org, Open Observatories, Open University.
Processing credit: Pip Stakkert the Jodrell Plank Observatory.

" Pip Stakkert has been reading MasterClass in Astronomy Now and decided to experiment with data captured with the PIRATE robotic telescope, using BVR, SHO, H-alpha and clear filters. The image shows lots of very faint nebulosity around the main areas of emission (red) and reflection (blue) nebulae. Even cursory inspection reveals dark nebulae (clouds of dust) that permeate he brighter nebulae. What a shame that this interesting  target does not rize above the Jodrell Plank Observatory's southern horizon". - Kurt Thrust current Director of the Jodrell Plank Observatory.

"Messier 20 (M20), also known as the Trifid Nebula, is a visually striking object in the constellation Sagittarius, approximately 4,100–5,200 light-years away from Earth. It’s an active star-forming region and a rare combination of three distinct types of nebulae.

 The Three Types of Nebulae in M20:

1. Emission Nebula (H II Region)

 Location: Central and red-pink regions of M20.

 Appearance: Glows with a reddish hue due to hydrogen-alpha emission.

Physical Process: Ultraviolet radiation from young, massive stars (especially an O7-type star near the core) ionizes the surrounding hydrogen gas. When electrons recombine with protons, they emit photons, most prominently in the Hα line at 656.3 nm.

Temperature: \~10,000 K.

Size: The ionized region spans several light-years in diameter.

2. Reflection Nebula

Location: Blue-hued regions, mostly in the northern part of M20.

Appearance: Blue due to scattered starlight by dust grains.

Physical Process: Unlike emission nebulae, reflection nebulae do not emit their own light. Instead, they reflect the light of nearby stars, often appearing blue because shorter wavelengths are scattered more efficiently.

Material: Fine dust particles, likely remnants of the same molecular cloud from which stars are forming.

3. Dark Nebula (Barnard 85)

Location: The dark lanes that appear to divide M20 into three lobes (hence “Trifid”).

Appearance: Opaque, dust-rich filaments silhouetted against the brighter emission background.

Physical Process: These are dense molecular clouds that obscure light from behind. The dust absorbs and blocks visible light but may emit infrared radiation.

Role: These regions often harbor the earliest phases of star formation—protostars hidden deep within.

Arrangement and Structure of M20:

M20 spans roughly 50 light-years across (angular diameter ~28 arcminutes) and is dominated by its trifurcated structure, with three main lobes formed by the dark dust lanes radiating outward from the central emission core. The central ionizing star system (dominated by HD 164492) is embedded within the emission nebula, energizing the gas and influencing star formation in the surrounding regions.

Stellar and Nebular Evolution in M20:

Birth: Star Formation

M20 lies in the Sagittarius Arm of the Milky Way, part of the larger Lagoon Nebula complex.

Star formation occurs as gravitational instabilities within dense parts of the molecular cloud cause it to collapse.

The resulting protostars accrete matter from surrounding disks and, once nuclear fusion begins, they ionize their surroundings.

Jets and outflows from these protostars can be seen in infrared and radio observations.

Life: H II Region Expansion:

The massive O and B-type stars live short lives (millions of years), continually ionizing the surrounding hydrogen and carving out expanding bubbles of hot gas.

UV radiation and stellar winds erode and compress nearby molecular clouds, potentially triggering sequential star formation (a process called radiation-driven implosion).

Over time, the surrounding gas becomes ionized and dispersed.

Death: Supernova and Nebula Dispersal:

The most massive stars will end their lives in core-collapse supernovae, enriching the interstellar medium with heavy elements.

These explosions can further compress nearby regions, initiating new waves of star formation.

Lower-mass stars become white dwarfs, and as the ionizing sources fade, the H II region will dissipate, leaving behind open star clusters.

In time, the dark nebulae will be consumed or dispersed, and M20 will fade as an active star-forming region

Scientific Significance:

M20 is a benchmark region for studying the interplay of different nebular types.

It showcases the feedback loop between star formation and cloud erosion.

It contains multiple Herbig-Haro objects (jets from young stars colliding with nearby gas) and proplyds (protoplanetary disks), making it crucial for understanding the early solar system’s analogs." - Professor G.P.T Chat visiting Astrophysicist at the Jodrell Plank Observatory.

 Summary Table:

| Feature                        | Description                                               

| Distance                      |~4,100–5,200 light-years                                

| Size                             |~50 light-years across                                   

| Main Nebula Types     | Emission, Reflection, Dark                                

| Dominant Star Type    | O7-type star (HD 164492A)                                

| Star Formation            | Active, with embedded protostars                          

| Long-Term Evolution   | Cluster + remnant dust after gas dispersal                                                                  and supernovae 

Markarian's Chain of Galaxies in the constellation Virgo

 

Markarian's Chain of Galaxies. Seestar S30 in EQ and Mosaic modes.
Credit: Pip Stakkert.

" Earlier in the year, Pip Stakkert was experimenting with the Seestar S30 and captured this rather poorly centred and under sampled mosaic of Markarian's Chain of Galaxies in the constellation Virgo. We will however return to this target next year when, once again, Virgo is high above our southern horizon in Lowestoft. Given more and longer sub exposures, the Seestar App now allows for 1-minute subs in EQ mode and mosaic format, we should be able to improve upon the image published above". - Kurt Thrust current Director of the Jodrell Plank Observatory.

"Markarian's Chain is a visually striking group of galaxies in the Virgo Cluster, named after Benjamin Markarian, who studied galaxy alignments and UV-active galaxies.While not all physically connected, several of the galaxies in the chain are interacting, providing valuable insights into galaxy evolution and cluster dynamics.

Notable members of the chain include:

• M84 (NGC 4374) – a giant elliptical galaxy.
• M86 (NGC 4406) – another bright elliptical galaxy.
• NGC 4435 and NGC 4438, often referred to as “The Eyes” because of their close pairing.
• Other galaxies such as NGC 4477, NGC 4461, and NGC 4458 are also part of the chain.

Some of the galaxies in the chain are gravitationally interacting, suggesting they are not just aligned by chance."  - Prof G.P.T. Chat visiting astrophysicist at the Jodrell Plank Observatory.

Altair and Tarazed in the constellation Aquila the Eagle.

 

The Summer Triangle above the Jodrell Plank Observatory.

"This time of year in the Northern Hemisphere, Altair and the less bright Tarazed are visible to the naked eye on clear transparent nights in Suffolk. Altair is one of the three bright stars which make up the 'Summer Triangle' asterism.  Altair is the alpha star in the constellation Aquila the Eagle. Tarazed a red giant and nearby Altair, is also in Aquila and is designated Gamma Aquilae.

This part of the summer night sky is awash with stars and dark nebulae (clouds of obscuring dust). Barnards 'E' can be seen in Kurt's image just above and to the right of Tarazed.

 

Kurt is very fond of using the spectrometer, designed and manufactured by our resident engineer, Jolene McSquint-Fleming, to create stellar spectral profiles". - Joel Cairo CEO of the Jodrell Plank Observatory.

Comparative Analysis of Low-Resolution Spectral Profiles of Altair and Tarazed

Prepared by: Prof G.P.T Chat, visiting astrophysicist at the Jodrell Plank Observatory

Date: July 5, 2025

This informal report presents a comparative analysis of the low-resolution spectral profiles of two nearby stars: Altair (α Aquilae) and Tarazed (γ Aquilae). Although they lie close together in the sky within the constellation Aquila, these stars differ significantly in spectral type, temperature, and luminosity class, which become evident when analyzing their spectral features.

Stellar Data Overview

Property Altair Tarazed

Spectral Type A7 V K3 II-III

Effective Temp. ~7,600 K ~4,300 K

Luminosity Class Main Sequence (V) Bright Giant (II-III)

Dominant Color White Orange-red

Spectral Profile Differences

1. Continuum Shape

Altair: Displays a blue-white continuum with a strong rise toward the shorter (bluer) wavelengths. This indicates a hotter surface temperature, consistent with its A-type classification.

Tarazed: Shows a redder continuum, peaking more in the longer (redder) wavelengths due to its significantly cooler surface temperature (~4300 K).

Interpretation: The blackbody radiation curves are shifted—Altair peaks in the UV-visible, Tarazed in the visible-red to near-infrared.

2. Balmer Line Strength

Altair: Prominent and broad hydrogen Balmer lines (especially Hα, Hβ, Hγ). This is typical of A-type stars where the hydrogen absorption is at its strongest due to optimal excitation conditions in the photosphere.

Tarazed: Very weak or absent Balmer lines. Cooler atmospheres do not excite hydrogen sufficiently to produce strong Balmer absorption features.

Interpretation: Balmer line strength peaks in mid-A spectral types and decreases sharply toward both hotter and cooler temperatures.

3. Metallic Lines and Molecular Bands

Altair: Metallic lines are present but not as strong, and molecular bands are virtually absent due to the high temperature preventing molecule formation.

Tarazed: Strong absorption lines of neutral metals such as Ca I, Fe I, and especially the Ca II infrared triplet. Also displays TiO molecular bands, common in cooler K and M-type giants.

Interpretation: Lower temperatures in Tarazed allow molecule formation and enhanced low-ionization metallic absorption. Molecular bands serve as clear markers of late-type stars.

4. Line Broadening

Altair: Broader spectral lines, especially in hydrogen and metal lines. This broadening is primarily due to rapid rotation (~250 km/s), which causes Doppler broadening across the stellar disk.

Tarazed: Narrower absorption lines. As a giant star, Tarazed rotates more slowly, and the lower surface gravity leads to less pressure broadening.

Interpretation: Rotation and gravity play key roles in line profile shape; Altair's fast spin contrasts strongly with Tarazed's more "settled" atmosphere.

Conclusion

In low-resolution spectra, Altair exhibits features typical of a hot, fast-rotating, hydrogen-rich main sequence star, dominated by strong Balmer lines and a blue continuum. In contrast, Tarazed, a cool and evolved bright giant, displays a redder spectrum dominated by metal lines and molecular absorption bands with relatively weak hydrogen features.

The differences in spectral profiles reflect underlying physical contrasts in temperature, gravity, chemical composition visibility, and rotational velocity, making these two stars a textbook example of spectral diversity across the HR diagram.

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