Massive stars such as WOH G64 and Stephenson 2–18 challenge our understanding of stellar evolution due to their extraordinary size and brightness. These red supergiants are among the largest known stars and are nearing the end of their life cycles, with predictions of their eventual supernova explosions. Studying these stars helps astronomers learn how massive stars evolve, lose mass, and collapse.

Of the two, Stephenson 2–18 is larger, boasting a radius approximately 2,150 times that of the Sun (about 1.4958 billion km), while WOH G64 has a radius about 1,540 times that of the Sun (1.07 billion km). WOH G64 resides in the Large Magellanic Cloud, has a mass between 25 and 40 solar masses, and shines 282,000 times brighter than our Sun. In contrast, Stephenson 2–18, located in the constellation Scutum, is noted as one of the largest and brightest red supergiants recorded. Both stars are at the twilight of their lifetimes, expelling material before their inevitable supernova events.

WOH G64 vs Stephenson 2-18

Comparing WOH G64 and Stephenson 2-18 highlights the extremes of stellar mass and size, as well as their likely fates as powerful supernovae. As astronomers examine their size, brightness, and structure, they gather important insights into the life cycles of the universe’s most massive stars.

Stephenson 2-18 is the larger star between the two, with a radius estimated at 2,150 times that of the Sun, approximately 1.4958 billion kilometers, establishing it as one of the largest known red supergiants. In contrast, WOH G64, a red supergiant in the Large Magellanic Cloud, lies about 168,000 light-years away and has a radius roughly 1,540 times that of the Sun (1.07 billion kilometers). As both stars approach the end of their lifetimes, they are anticipated to explode as supernovae. While WOH G64 has a mass ranging from 25 to 40 solar masses and is 282,000 times brighter than the Sun, Stephenson 2-18 stands out for its extraordinary size and luminosity, situated in the Stephenson 2 star cluster in the constellation Scutum, around 19,570 light-years distant.

These stars offer critical insights into the characteristics of red supergiants and their final phases before undergoing supernova explosions. Surrounded by a dense dust cloud due to significant mass loss, WOH G64 aids scientists in understanding how massive stars expel material prior to their demise. Research into its atmosphere reveals aspects of stellar mass loss and the transition into supernova remnants or black holes. Similarly, despite its immense size, Stephenson 2–18 exists within a larger cosmic environment where even the largest stars are outmatched by galaxies. Studying these phenomena enhances our comprehension of the extreme conditions that influence stellar evolution.

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Comparative table: WOH G64 vs Stephenson 2-18

WOH G64 vs Stephenson 2-18: A key comparison

Overall size

Stephenson 2–18 is significantly larger than Woh G64. WOH G64 has an approximate radius of 1,540 times that of the sun, which is around 1.07 billion kilometers. While Stephenson 2–18 has a radius of about 2,150 times the sun’s radius, approximately 1.4958 billion kilometers. This makes Stephenson 2-18 one of the largest known stars, much bigger than WOH G64.

Strength

WOH G64 is likely more massive than Stephenson 2-18. WOH G64 has a mass between 25 to 40 times that of the Sun, whereas Stephenson 2-18 has a mass of approximately 30 solar masses or less. This means WOH G64 may have a stronger gravitational force. However, both stars are highly unstable and lose material rapidly as they near the end of their life cycles.

Type of object

Both WOH G64 and Stephenson 2-18 are red supergiant stars nearing the end of their life cycles. Woh G64 is located in a large Magellanic Cloud and is rapidly losing mass. Stephenson 2–18, lies in the Milky Way and is known for its huge size and luminosity. Both the stars are unstable and eventually explode as Supernova, which marks their final stages of development.

Mass

WOH G64 is estimated to have a mass between 25 and 40 solar masses, which is approximately 4.972 × 10³¹ kilograms at the upper limit. Stephenson has a mass of about 30 solar masses or less, causing Woh G64 to potentially be more large-scale. However, the two stars are rapidly shedding mass near the end of their life cycle.

Luminosity

Both WOH G64 and Stephenson 2–18 are highly luminous red supergiants, but Stephenson 2–18 is quite bright. The WOH G64 has an estimated luminosity of about 282,000 times the Sun, while Stephenson 2–18 is considered about 440,000 times more luminous than the Sun. This makes Stephenson 2–18 a more powerful star in terms of energy production, radiating light in immense amounts despite its cooler surface temperature.