Hubblecast 71: Visible echoes around RS Puppis

Summary

The Hubble Space Telescope captured a light echo around the variable star RS Puppis, revealing its pulsating nature and cosmic gas interactions. This phenomenon, similar to an audible echo, helps astronomers measure cosmic distances, with RS Puppis being determined to be 6500 light years away.

Takeaways

• 🌌 Hubble has captured a light echo around the variable star RS Puppis.
• 🌟 Stars like RS Puppis, a Cepheid variable, undergo changes in brightness and size over time.
• 🔍 RS Puppis varies in brightness by almost a factor of five every 40 days.
• 🌫️ The star is surrounded by a thick shroud of cosmic gas and dust.
• 🎥 Hubble observed RS Puppis over five weeks, creating a time-lapse video of its brightness changes.
• 🌐 The perceived expansion of gas around the star is actually a light echo, not actual movement.
• 💫 Light echoes are caused by light reflecting off progressively distant shells of dust and gas, reaching Earth at different times.
• 🌌 A similar light echo was observed around the variable star V838 Monocerotis in 2002.
• 📏 Cepheid variables like RS Puppis are used as cosmic distance markers due to the correlation between their pulsation period and intrinsic brightness.
• 📍 The distance to RS Puppis has been measured to be around 6500 light years, marking the most accurate measurement for such a star.

Q & A

What is an echo?

An echo is a reflection of sound or light that arrives at the listener or observer later than the direct sound or light, due to it taking a longer path by bouncing off surrounding objects.

What is a light echo?

A light echo is an optical illusion caused by the reflection of light from progressively more distant shells of dust and gas surrounding a star, making it appear as if the gas around the star is expanding outwards.

What is RS Puppis?

RS Puppis is a variable star, specifically a Cepheid variable, that varies in brightness by almost a factor of five every 40 days or so and is engulfed in a thick shroud of cosmic gas and dust.

Why do variable stars like RS Puppis pulsate?

Variable stars pulsate because they become unstable as most of their core hydrogen has been consumed, causing them to expand and shrink over a number of days or weeks.

How does the Hubble Space Telescope capture a light echo?

The Hubble Space Telescope captures a light echo by observing a variable star like RS Puppis over a period of time, noting how the reflected light from dust and gas arrives later than the direct light.

What is the significance of observing light echoes around stars like RS Puppis?

Observing light echoes around stars like RS Puppis helps scientists understand the dusty environment around these stars and provides insights into their pulsation periods and intrinsic brightness.

How is RS Puppis used as a cosmic distance marker?

RS Puppis is used as a cosmic distance marker because the period of its pulsations is directly connected to its intrinsic brightness, allowing astronomers to measure its distance.

What is the distance to RS Puppis as measured by astronomers?

Astronomers have measured the distance to RS Puppis to be around 6500 light years, which is the most accurate distance to such a star ever measured.

What is the role of the Hubble mission in studying stars like RS Puppis?

The Hubble mission, a project of international cooperation between NASA and the European Space Agency, plays a crucial role in studying stars like RS Puppis by capturing detailed images and observations that help in understanding their properties and behaviors.

What is the significance of the Hubble Space Telescope's observations of light echoes?

The Hubble Space Telescope's observations of light echoes provide a unique way to study the interaction of light with cosmic dust and gas, and also help in measuring distances to distant stars more accurately.

What is the Hubblecast and where can more information be found?

The Hubblecast is a production by ESA/Hubble at the European Southern Observatory in Germany, providing updates and information on the Hubble mission. More information can be found at www.spacetelescope.org.