Carbon Stars - La Superba - Low resolution Spectral Profile

 

Kurt loves a bit of stellar spectroscopy and encouraged by his friend and sometimes astronomical collaborator, Professor GP, he captured the spectral data for the amazing Carbon Star - La Superba, using the JPO's 127mm. apo-refractor and a spectrometer designed and 3d printed by our on-site engineer Jolene McSquint -Fleming in the observatory's clean room'. - Joel Cairo CEO of the Jodrell Plank Observatory.

For an absolutely fantastic image of this 'very red star' follow the link.

https://apod.nasa.gov/apod/ap081218.html

"For an explanation of this 'cool', in every sense of the word, star, I asked the JPO's visiting physicist, G.P.T. Chat Phd, to describe its general features and spectral details using a comparative methodology" - Kurt Thrust current Director of the Jodrell Plank Observatory.

La Superba and Stellar Evolution: A Comparative Analysis on the Hertzsprung-Russell Diagram

Introduction

Stars are the fundamental building blocks of galaxies, and their life cycles reflect the underlying physics that governs the universe. Among the many types of stars observed, carbon stars represent a fascinating late stage in stellar evolution. One of the most prominent and well-studied carbon stars is La Superba, also known as Y Canum Venaticorum. This essay explores La Superba's characteristics in detail and places it in context with several other well-known stars using the Hertzsprung-Russell (H-R) diagram.

La Superba: An Overview

La Superba is located in the constellation Canes Venatici, visible in the northern hemisphere, especially during spring. Its coordinates (J2000 epoch) are:
- Right Ascension: 12h 45m 07.83s
- Declination: +45° 26′ 24.9″

It lies approximately 710 light-years from Earth and is classified as a carbon-rich red giant — one of the brightest of its kind visible to the naked eye. As a semi-regular variable star, its apparent magnitude varies from +4.9 to +6.3.

La Superba's physical parameters make it particularly interesting:
- Temperature: ~2,750 K
- Luminosity: ~9,000 L☉ (9000 x Sun's luminosity)
- Radius: ~400–500 R☉ (400 to 500 x Sun's radius)

It is a C-type (carbon) star, having undergone internal helium burning via the triple-alpha process, which produces carbon that is brought to the surface through convective dredge-up. This enrichment gives rise to a spectrum rich in carbon molecules, including C₂ (Swan bands), CN, and CH. These features result in deep molecular absorption bands, giving the star a very red appearance and making it a textbook example of a cool, evolved star on the Asymptotic Giant Branch (AGB).

Spectral Features

La Superba’s spectral type is typically classified as C6,2e in the revised carbon star classification system. It exhibits strong molecular absorption features and sometimes weak emission lines like H-alpha during pulsation events. The absence of oxygen-bearing molecules like TiO, common in M-type giants, highlights the dominance of carbon chemistry in its atmosphere.

Position on the H-R Diagram

The Hertzsprung-Russell diagram plots stars by their luminosity (vertical axis) and surface temperature (horizontal axis, decreasing rightward). La Superba occupies the upper-right portion of the H-R diagram — a region dominated by cool, highly luminous red giants and supergiants.

To provide comparative context, several other prominent stars are also plotted:
- The Sun – A G-type main sequence star with a surface temperature of 5,778 K and luminosity of 1 L☉.
- Deneb – A luminous blue-white supergiant (~8,500 K, 196,000 L☉).
- Sirius – A bright A-type main-sequence star (~9,940 K, 25.4 L☉).
- Arcturus – An orange giant (~4,286 K, 170 L☉).
- Capella – A system of G-type giants (~5,700 K, 78.7 L☉).
- Betelgeuse – A red supergiant (~3,500 K, 126,000 L☉).
- Castor – An A-type star (~10,100 K, 52.4 L☉).
- Pollux – An orange giant (~4,865 K, 43 L☉).
- Vega – A well-known A-type main-sequence star (~9,602 K, 40.1 L☉).

These stars cover a range of spectral types and evolutionary stages, allowing us to place La Superba within the broader context of stellar evolution.

H-R Diagram

Conclusion

La Superba serves as a striking example of late stellar evolution and highlights the diversity of stars when viewed through the lens of temperature and luminosity. Its placement on the H-R diagram underscores the dramatic changes stars undergo during their lifespans. Comparing La Superba with other well-known stars reveals the full spectrum of stellar development — from main-sequence hydrogen burners to evolved giants and future white dwarfs". - G.P.T. Chat Phd visiting physicist at the Jodrell Plank Observatory 

Globular star cluster Messier 3 or NGC 5272

 

Messier 3 Credit: Kurt Thrust - Seestar S30 in EQ mode.
Image cropped from Seestar widefield FOV.

"Messier 3 (M3), also known as NGC 5272, is a globular star cluster located in the northern constellation Canes Venatici. It is one of the brightest and most well-studied globular clusters in the sky.

Location and Observational Data

• Right Ascension: 13h 42m 11.62s

• Declination: +28° 22′ 38.2″

• Distance from Earth: ~33,900 light-years (10.4 kpc)

• Distance from Galactic Center: ~38,800 light-years (11.9 kpc)

• Position relative to Galactic Plane: ~31,600 light-years (9.7 kpc) above

• Constellation: Canes Venatici

• Apparent Magnitude: 6.39

• Apparent Size: 18 arcminutes

Physical Characteristics

• Estimated Age: ~11.4 billion years

• Mass: ~450,000 solar masses

• Radius: ~103 parsecs (335.9 light-years)

• Tidal Radius: ~113 parsecs (370 light-years)

• Absolute Magnitude: -8.93

• Metallicity ([Fe/H]): -1.34 dex

• Spectral Type: F2 (overall cluster classification)

Star Population and Variability

• Total Stars: ~500,000

• Variable Stars: 274 known, including 133 RR Lyrae variables

• Brightest Stars: Magnitude ~12.7

• Average Brightness of 25 Brightest Stars: ~14.23 mag

Discovery and Historical Significance

• Discovered by: Charles Messier on May 3, 1764

• First mistaken for: A nebula without stars

• Resolved into stars by: William Herschel in 1784

• Notable for: Having the highest number of variable stars among known globular clusters

The uncropped widefield image from the Seestar S30 post processed mainly using Affinity Photo 

Messier 3 is a fascinating object for astronomers due to its rich stellar population and high concentration of variable stars. Its isolation from the galactic plane makes it an excellent target for studying globular cluster evolution. Given your curiosity about astronomy, George, I imagine you’d appreciate the intricate details of its stellar dynamics! Would you like to explore how its variable stars contribute to distance measurements in astrophysics?

Globular star clusters like Messier 3 (M3) are some of the oldest stellar structures in the universe, forming during the early epochs of galaxy evolution. Their formation is still an area of active research, but here’s a breakdown of the leading theories and processes involved:

Formation Process

1. Primordial Collapse:

   • Globular clusters likely formed from massive gas clouds in the early universe, collapsing under gravity.

   • These clouds were enriched with low-metallicity gas, meaning they contained mostly hydrogen and helium, with very few heavier elements.

2. Rapid Star Formation:

   • The gas cloud underwent intense bursts of star formation, leading to the creation of hundreds of thousands of stars in a short period.

   • Unlike open clusters, globular clusters formed all at once, rather than gradually over time.

3. Gravitational Binding:

   • The stars remained gravitationally bound due to their high density and mutual attraction.

   • This led to the spherical shape characteristic of globular clusters.

4. Galactic Influence:

   • Many globular clusters formed outside the main disk of galaxies, possibly in dwarf galaxies or as remnants of galactic mergers.

   • Over time, they were captured by larger galaxies like the Milky Way.

5. Long-Term Evolution:

   • As globular clusters age, stellar interactions cause some stars to migrate outward while others fall toward the core.

   • Blue stragglers, a peculiar type of star found in globular clusters, may result from stellar collisions or mergers.

Why Are They So Old?

• The stars in globular clusters are typically Population II stars, meaning they formed early in the universe’s history.

• Their low metallicity suggests they originated before significant amounts of heavier elements were synthesized by supernovae.

• The lack of new star formation in globular clusters is due to the absence of gas, which was either used up or expelled early in their history.

M3, like other globular clusters, provides a window into the early universe, helping astronomers understand galaxy formation and stellar evolution. Given your curiosity about astronomy, George, I imagine you’d appreciate how these clusters serve as cosmic fossils! Would you like to explore how their dynamics influence galactic evolution?

Globular star clusters like Messier 3 (M3) are some of the oldest stellar structures in the universe, forming during the early epochs of galaxy evolution. Their formation is still an area of active research, but here’s a breakdown of the leading theories and processes involved:

Formation Process

1. Primordial Collapse:

   • Globular clusters likely formed from massive gas clouds in the early universe, collapsing under gravity.

   • These clouds were enriched with low-metallicity gas, meaning they contained mostly hydrogen and helium, with very few heavier elements.

2. Rapid Star Formation:

   • The gas cloud underwent intense bursts of star formation, leading to the creation of hundreds of thousands of stars in a short period.

   • Unlike open clusters, globular clusters formed all at once, rather than gradually over time.

3. Gravitational Binding:

   • The stars remained gravitationally bound due to their high density and mutual attraction.

   • This led to the spherical shape characteristic of globular clusters.

4. Galactic Influence:

   • Many globular clusters formed outside the main disk of galaxies, possibly in dwarf galaxies or as remnants of galactic mergers.

   • Over time, they were captured by larger galaxies like the Milky Way.

5. Long-Term Evolution:

   • As globular clusters age, stellar interactions cause some stars to migrate outward while others fall toward the core.

   • Blue stragglers, a peculiar type of star found in globular clusters, may result from stellar collisions or mergers.

Why Are They So Old?

• The stars in globular clusters are typically Population II stars, meaning they formed early in the universe’s history.

• Their low metallicity suggests they originated before significant amounts of heavier elements were synthesized by supernovae.

• The lack of new star formation in globular clusters is due to the absence of gas, which was either used up or expelled early in their history.

M3, like other globular clusters, provides a window into the early universe, helping astronomers understand galaxy formation and stellar evolution. Given your curiosity about astronomy, George, I imagine you’d appreciate how these clusters serve as cosmic fossils! Would you like to explore how their dynamics influence galactic evolution?

How do globular clusters impact galactic evolution?

Globular clusters play a significant role in the evolution of galaxies, influencing their structure, dynamics, and star formation history. Here’s how:

1. Galactic Halo Formation and Enrichment

• Globular clusters are among the oldest stellar systems, forming early in a galaxy’s history.

• Their low metallicity suggests they originated before significant enrichment by supernovae.

• As they evolve, they contribute heavy elements to the interstellar medium, enriching future generations of stars.

2. Stellar Dynamics and Galactic Structure

• Globular clusters orbit within a galaxy’s halo, often following highly elliptical paths.

• Their gravitational interactions help shape the galactic potential, influencing the motion of stars and dark matter.

• Some clusters are disrupted over time, spreading stars throughout the halo.

3. Galactic Mergers and Evolution

• During galaxy mergers, globular clusters can be captured by the larger galaxy.

• This process helps trace the assembly history of galaxies, revealing past interactions.

• Some clusters may originate from dwarf galaxies that were absorbed by larger galaxies.

4. Black Hole and Dark Matter Studies

• Some globular clusters contain intermediate-mass black holes, providing insights into black hole formation.

• Their motions help astronomers study the distribution of dark matter in galaxies.

5. Star Formation and Feedback

• While globular clusters no longer form new stars, their stellar winds and supernovae influence surrounding gas.

• This feedback can regulate star formation in the galaxy.

Globular clusters like Messier 3 serve as cosmic fossils, preserving information about the early universe and galaxy formation." 

- Charlie Server - Copilot at the Jodrell Plank Observatory

Interacting Galaxies NGC 5194 (Messier 51) and NGC 5195

 

NGC 5194 and NGC 5195. Image Credit: Pip Stakkert - Jodrell Plank Observatory. Data Credits: telescope.org, Open Observatories, Open University and Jodrell Plank Observatory. 

"The  interacting galaxies, known as Messier 51 or The Whirlpool, ride high in the late spring Northern Hemisphere sky, and in the constellation Canes Venatici. This pair of gravitationally interacting galaxies are some 31 million light years distant and the larger of the two is approximately 77,000 light years across. M51 was the first galaxy to be identified as having a spiral structure in 1845 by Lord Rosse from his observatory in Ireland.

We first pointed the Jodrell Plank Observatory's little Seestar S30 at  this galactic pair and thought how small these huge galactic structures looked when imaged with a telescope having a large field of vision.

Uncropped and stacked image downloaded from the Seestar S30.
Credit: Pip Stakkert.

We decided to use the PIRATE robotic telescope on Mount Teide Tenerife to capture M 51 and apply the data, imaged in white light and hydrogen alpha wavelengths, as a luminance channel  for the colour data we captured with the Seestar S30. The Seestar has an aperture of 30mm and the PIRATE telescope has an aperture of 600mm. So our image is a veritable 'little and large' collaboration. The two data sets were combined using the excellent and venerable software 'Registar'.

An interesting feature of both our above images is, the 'tidal feature', or northwest plume of gas emanating from the galactic centre of the larger NGC 5194 and extending some 140,000 light years to NGC 5195.  Close inspection of the top combined image shows a burst of star formation underway towards the the centre of NGC 5194" - Joel Cairo CEO of the Jodrell Plank Observatory (The Uk's most Easterly Astronomical Observatory).
 

Messier 87 and Virgo A

 

Messier 87 in the Constellation Virgo. PIRATE robotic Telescope Mount Teide, BVR filters, Hydrogen alpha filter  and Clear filter combined. Over-layed with Ultra violet data from the GALEX space Telescope.  Data Credits: telescope.org, Open Observatories, Open University, Astrometry net and NASA.
Image Credit: Pip Stakkert Jodrell Plank Observatory.

Annotated version M87: Credit Astrometry net.

Annotated and enlarged section of the galaxy core
to better show the plasma jet. Image credit: Kurt Thrust.

"Pip Stakkert combined the data from these two research grade telescopes to show the jet of energetic plasma issuing from the galaxy's massive central black hole and extending 4900 light years outwards. You can just see the jet at the centre of the large elliptical galaxy at approximately 10 -o'- clock position.

The plasma jet from the core of M87 issues from the supermassive black hole at its center. This black hole, which was famously imaged by the Event Horizon Telescope, is actively accreting matter. As material falls toward the black hole, some of it gets caught in powerful magnetic fields and is ejected outward at nearly the speed of light, forming a relativistic jet.

These jets are powered by the immense gravitational and electromagnetic forces near the black hole. The plasma is accelerated along magnetic field lines, creating a highly energetic stream that extends thousands of light-years into space. Observations suggest that the jet is composed of charged particles, primarily electrons, moving at relativistic speeds, which makes it a strong source of radio and X-ray emissions.

The elliptical galaxy Messier 87 is thought to contain more than a trillion stars, is almost spherical having a diameter of 120,000 light years and is over 50 million light years away. With an apparent magnitude of 9.6 it is visible as a small smudge of light through a small telescope. It can be found in the sky within the boundaries of the constellation Virgo. It is visible in our images as a large ball of diffuse light with a bright central core. The jet can be seen emanating from this core. M87 is too far away to make out any of the constituent stars. The stars which you see in our images are located much closer to home in our Milky Way galaxy. It is thought that M87 although very large in mass sits within an absolutely enormous surrounding halo of dark matter which can only be observed by its gravitational influence on other galaxies within the local group of galaxies". - Kurt Thrust current director of the Jodrell Plank Observatory.