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