Exoplanets and Proxima B
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Questions and Answers

What does a redshift in radial velocity indicate?

  • The object is moving away from the observer. (correct)
  • The object is moving toward the observer.
  • The object's velocity is constant.
  • The object is at rest relative to the observer.

Which of the following instruments is specifically designed to measure radial velocities of stars?

  • Astronomical Radial Velocity Analyzer (ARVA)
  • Spectroscopic Analysis Device (SAD)
  • High Accuracy Radial Velocity Planet Searcher (HARPS) (correct)
  • Ultraviolet and Visual Echelle Spectrograph (UVES)

What percentage of solar-type stars are estimated to have Earth-sized planets in their habitable zones?

  • 10%
  • 20% (correct)
  • 50%
  • 5%

What is the mass of Proxima b compared to Earth?

<p>1.3 times the mass of Earth (A)</p> Signup and view all the answers

What is the significance of the discovery of 51 Pegasi b in relation to exoplanet research?

<p>It was the first exoplanet discovered orbiting a sun-like star. (A), It has made the possibility of finding new Earth-like planets more realistic. (C)</p> Signup and view all the answers

What is the primary goal of using spectroscopy in the study of exoplanets?

<p>To gauge light received at different wavelengths and reveal physical properties. (A)</p> Signup and view all the answers

Why might life be considered to be extremely rare on planets outside of Earth?

<p>Only Earth-like planets around Sun-like stars may support life. (D)</p> Signup and view all the answers

How far away is Proxima Centauri, the star around which Proxima b orbits?

<p>4.2 light-years (C)</p> Signup and view all the answers

What challenges are often associated with the habitability of newly discovered exoplanets?

<p>Tidal locking and stellar winds (D)</p> Signup and view all the answers

How long is Proxima b's orbital period around Proxima Centauri?

<p>11.2 days (D)</p> Signup and view all the answers

What percentage of exoplanet candidates are considered potentially habitable?

<p>10% (A)</p> Signup and view all the answers

Which astronomer is associated with the discovery of Proxima b?

<p>Guillem Anglada-Escudé (D)</p> Signup and view all the answers

What is the orbital period of Proxima b reported in the findings?

<p>Approximately 11 Earth days (D)</p> Signup and view all the answers

What aspect of Proxima b's environment is primarily questioned by astronomers?

<p>Its habitability for life (A)</p> Signup and view all the answers

What discovery procedures were trialed by Anglada-Escudé to gather information about exoplanets?

<p>Transit method and radial velocity (B)</p> Signup and view all the answers

In what year was Proxima b discovered?

<p>2016 (B)</p> Signup and view all the answers

What was the main focus of the work by Anglada-Escudé et al. in 2016?

<p>Identifying a terrestrial planet candidate around Proxima Centauri (C)</p> Signup and view all the answers

Which of the following studies discusses the risks for life on Proxima b?

<p>Siraj and Loeb 2020 (A)</p> Signup and view all the answers

What is one of the primary objectives of the HARPS survey as mentioned in the 2011 study?

<p>Detecting very low-mass planets around certain stars (D)</p> Signup and view all the answers

Which publication discusses the methods of planetary spectroscopy in relation to exoplanets?

<p>Encrenaz 2022 (D)</p> Signup and view all the answers

What was a key finding of Dong et al. in their 2017 research on Proxima Centauri b?

<p>Atmospheric loss may affect Proxima Centauri b's habitability (D)</p> Signup and view all the answers

Why is Proxima Centauri expected to live longer than the Sun?

<p>It has a smaller size than the Sun. (B)</p> Signup and view all the answers

What effect do stellar winds have on a planet's atmosphere?

<p>They can deplete the atmosphere over time. (C)</p> Signup and view all the answers

How much of Earth's atmospheric oxygen has been lost over 3 billion years?

<p>2% (C)</p> Signup and view all the answers

What is a potential threat to life on Proxima b due to asteroids?

<p>Higher chances of extinction. (C)</p> Signup and view all the answers

What advancements can be expected in the future to aid in exploring exoplanets?

<p>Improved spectrometers. (C)</p> Signup and view all the answers

Which instruments have been crucial for exploring exoplanets like Proxima b?

<p>Radial velocity instruments. (A)</p> Signup and view all the answers

What is the maximum estimated time for Proxima b's atmosphere to deplete completely?

<p>100 million years. (D)</p> Signup and view all the answers

What could happen to Proxima b's habitability over time?

<p>It may evolve to strengthen its atmosphere. (A)</p> Signup and view all the answers

What does the 11.2-day period signify in the context of the Doppler signal detection?

<p>The periodicity of a detected signal from Proxima b (D)</p> Signup and view all the answers

Why should astronomers compare Proxima b to Earth when assessing habitability?

<p>To understand similarities and differences with a known habitable planet (C)</p> Signup and view all the answers

What potential condition is associated with Proxima b that raises questions about its habitability?

<p>Rotation leading to tidal locking (C)</p> Signup and view all the answers

What is the effective temperature of Proxima Centauri compared to the Sun?

<p>Approximately 3,050 Kelvin (C)</p> Signup and view all the answers

How does the distance of Proxima b from Proxima Centauri compare with Earth’s distance from the Sun?

<p>Proxima b is much closer to its star than Earth is to the Sun (C)</p> Signup and view all the answers

What percentage of the Sun's luminosity does Proxima Centauri have?

<p>0.15% (B)</p> Signup and view all the answers

What misconception about Proxima b's location is addressed in the context of habitability?

<p>Proxima b is in the livable zone, hence it is habitable (B)</p> Signup and view all the answers

What phenomenon is suggested as a possibility affecting Proxima b's climate conditions?

<p>Tidal heating due to proximity to Proxima Centauri (A)</p> Signup and view all the answers

Flashcards

Exoplanet

A planet that orbits a star outside of our solar system.

51 Pegasi b

An exoplanet discovered in 1995 orbiting the star 51 Pegasi.

Light-year

The distance light travels in one year, approximately six trillion miles.

Proxima b

An exoplanet orbiting Proxima Centauri, the closest star to Earth.

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Proxima Centauri

The closest star to our solar system.

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Orbital Period

The time it takes for a planet to complete one orbit around its star.

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Semi-major Axis

Half of the longest diameter of an elliptical orbit.

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Habitability

The potential for a planet to support life.

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Radial Velocity

The velocity of an object between the observer and the object, showing how fast it's moving towards or away.

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Redshift

Indicates positive radial velocity; the object is moving away from the observer.

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Blueshift

Indicates negative radial velocity; the object is moving towards the observer.

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HARPS

High Accuracy Radial Velocity Planet Searcher - an instrument used in detecting planets.

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Habitable Zone (HZ)

The region around a star where a planet can have liquid water on its surface and a stable atmosphere.

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Proxima b

A potentially habitable exoplanet orbiting Proxima Centauri.

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Proxima Centauri

The closest star to our Sun.

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Orbital Period (Proxima b)

The time it takes for Proxima b to complete one orbit around Proxima Centauri (about 11.2 days).

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11.2-day period

The time it takes for the signal (Doppler shift) from Proxima b to repeat, indicating its orbit.

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Proxima b's Orbit

Proxima b orbits Proxima Centauri, closely around its star.

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Proxima Centauri's HZ

The region around Proxima Centauri where a planet may have liquid water on its surface.

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Proxima b's Habitability

The question of whether Proxima b can support life.

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Tidal Locking

When one side of a planet always faces its star.

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Effective Temperature

The temperature of a star as measured by its radiated energy.

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Astronomical Unit (AU)

A unit of measurement for astronomical distances equal to the average distance between the Earth and the Sun.

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Proxima b distance from Proxima Centauri

0.05 AU = 7.5 million km.

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Proxima Centauri

The star closest to our solar system.

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Proxima b's Orbit

Proxima b orbits its star, Proxima Centauri, at a close distance.

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Habitable Zone

The region around a star where a planet could potentially support liquid water.

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Proxima b's Potential Habitability

The possibility that the conditions on Proxima b support life.

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Radial Velocity Method

A method of detecting exoplanets by measuring the slight wobble of a star caused by an orbiting planet.

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Proxima b's lifespan

Proxima b might not have a very long atmosphere, potentially losing it in a few hundred million years (100,000,000) due to its star's high stellar winds.

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Stellar Wind Effect

Fast particles from a star can affect a planet's atmosphere, potentially disrupting its environment.

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Proxima b's habitability

Proxima b's potential habitability depends on factors like its atmosphere's durability, and asteroid impacts.

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Habitable Zone (HZ)

The region around a star where a planet can potentially support liquid water on its surface and a stable atmosphere.

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Radial Velocity Instruments

Tools used to find exoplanets by detecting the slight movement of stars due to the gravitational pull of orbiting planets.

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Exoplanet Atmosphere Weakening

A planet's atmosphere can get thinner over time due to the effects of stellar winds and other factors.

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Proxima Centauri's Longevity

Proxima Centauri will live longer than our Sun due to its smaller size.

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Debris Belts Impact

Debris belts near planets can cause asteroid impacts, threatening life.

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Study Notes

Exoplanet Proxima B

  • An exoplanet is a planet orbiting a star outside our solar system.
  • 51 Pegasi b was first discovered in 1995, orbiting 51 Pegasi.
  • 51 Pegasi is approximately 48 light-years from Earth.
  • A light-year is equivalent to about 6 trillion miles.
  • The discovery of 51 Pegasi b sparked interest in finding other potentially Earth-like planets.
  • Other exoplanets discovered before Proxima b include Gamma Cephei Ab (1988) and PSR B1257+12 B (1992).

Significance of Proxima B Discovery

  • Proxima b was announced in 2016 by Guillem Anglada-Escudé.
  • It orbits Proxima Centauri, the closest star to our solar system.
  • Proxima Centauri is approximately 4.2 light-years away.
  • The article "A Terrestrial Planet Candidate in a Temperate Orbit Around Proxima Centauri" discusses Proxima b's discovery and potential habitability.
  • Proxima b's discovery increased curiosity in the possibility of finding an Earth-like planet.

Methods for Detecting Exoplanets

  • Radial velocity instruments, like HARPS, measure the velocity of celestial objects relative to Earth to detect exoplanets.
  • Radial velocity is the speed an object moves towards/away from an observer.
  • "Redshift" indicates the object is moving away, while "blueshift" indicates it's moving towards the observer
  • UVES is another instrument that detects light from exoplanets to determine temperature and other physical properties.
  • Spectroscopy studies the light emitted by planets to learn about their composition and density.

Proxima b's Characteristics

  • Proxima b has a mass approximately 1.3 times that of Earth.
  • It orbits Proxima Centauri with a period of 11.2 days.
  • By analyzing Doppler signals, scientists can measure the radial velocity.
  • These patterns are similar to a police siren's varying wavelengths based on direction of the siren.

Habitability Considerations

  • Proxima b's location within Proxima Centauri's "habitable zone" doesn't guarantee habitability (possible tidal locking).
  • The habitable zone is an area around a star where a planet may have conditions suitable for liquid water on its surface and possibly life.
  • Proxima Centauri's characteristics (smaller size, cooler temperature) may affect the habitability of Proxima B.
  • Tidal locking could create extreme temperature differences between the planet's surfaces, impacting potential habitability.
  • 0.15% of the Sun's luminosity vs. Proxima Centauri; 0.05 au away from Proxima Centauri.

Concerns Regarding Exoplanets

  • Effects of stellar winds on exoplanet atmospheres, which could strip away atmospheric components (like oxygen).
  • Possible asteroid belts near exoplanets, increasing the risk of extinction-level events.
  • Advances in technology will create better spectrometers/methods that will enable better studies/discoveries.

Future Exploration of Exoplanets

  • Further study is needed to evaluate Proxima b's habitability.
  • Continued observations and advancements in technology (spectrometers) are needed.
  • Proxima b might not be the next Earth for constantly evolving humans, but the current technology and future research may prove that otherwise.

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Cluster 70A Final Draft: The Significance of Proxima B PDF

Description

Explore the fascinating world of exoplanets, particularly focusing on Proxima B, the closest known Earth-like planet. This quiz covers the history of exoplanet discoveries, significant findings, and methods used for detection. Test your knowledge on the significance of Proxima B and its discovery.

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