Science & Astronomy

Exoplanet Discovery: The 7 Earth-Sized Planets of TRAPPIST-1 in Pictures

The TRAPPIST-1 star, an ultra-cool dwarf, has seven Earth-size planets orbiting it. Original Image
Credit: NASA/JPL-Caltech

TRAPPIST-1: A Star with 7 Earths?

This artist’s impression depicts what the view might be like from a planet in the TRAPPIST-1 system. Original Image
Credit: ESO/M. Kornmesser/<a href="http://www.spaceengine.org/">spaceengine.org</a>

On Feb. 22, 2017, scientists announced the discovery of TRAPPIST-1, an alien solar system with at least seven Earth-sized planets. See pictures of the discovery here. Read the Full Story.

Artist's impression of the cool dwarf star TRAPPIST-1 and its exoplanets, which lie 39 light-years from Earth.

TRAPPIST-1 System

The TRAPPIST-1 star, an ultra-cool dwarf, has seven Earth-size planets orbiting it. Original Image
Credit: NASA/JPL-Caltech

The seven planets in the TRAPPIST-1 system range in mass from 75 percent to 110 percent that of Earth. At least three of the worlds likely have surface temperatures that allow liquid water to exist, scientists say.

TRAPPIST-1 Orbit Diagram

This diagram shows the orbits of the seven known plants in the TRAPPIST-1 system. Original Image
Credit: ESO/O. Furtak

Diagram of the orbits of the TRAPPIST-1 worlds, compared to those of Jupiter's Galilean moons, Mercury, Venus and Earth.

View from the Surface of a TRAPPIST-1 Planet

Imagine standing on the surface of the exoplanet TRAPPIST-1f. This artist's concept is one interpretation of what it could look like. Original Image
Credit: NASA/JPL-Caltech

Artist's impression of the view from the surface from one of the seven Earth-size planets in the TRAPPIST-1 system.

TRAPPIST-1 Planets and the Solar System's Rocky Worlds

This chart shows, on the top row, artist conceptions of the seven planets of TRAPPIST-1 with their orbital periods, distances from their star, radii and masses as compared to those of Earth. The bottom row shows data about Mercury, Venus, Earth and Mars. Original Image
Credit: NASA/JPL-Caltech

Characteristics of the seven TRAPPIST-1 worlds, compared to the rocky planets in our solar system.

2016 Discovery: 3 TRAPPIST-1 Planets

Scientists using the TRAPPIST-1 telescope have discovered three alien planets 40 light-years from Earth that just might support life. Original Image
Credit: ESO

In 2016, astronomers announced the discovery of three Earth-size worlds in the TRAPPIST-1 system. Additional observation upped eventually upped that tally to seven.

TRAPPIST-1 Planet: Surface View

Scientists using the TRAPPIST-1 telescope have discovered three alien planets 40 light-years from Earth that just might support life. Original Image
Credit: ESO

Another artist's impression of the view from a TRAPPIST-1 planet's surface.

TRAPPIST-1 Planetary System: Artist's Concept

Artist's illustration of two Earth-size exoplanets crossing the face of the dim star TRAPPIST-1, which lies just 39 light-years from Earth. Original Image
Credit: NASA, ESA, G. Bacon (STScI) and J. de Wit (MIT)

Artist's illustration of two Earth-size exoplanets crossing the face of the dim star TRAPPIST-1, which lies just 39 light-years from Earth.

TRAPPIST-1 System: Size Comparison

Comparing the sizes of the main objects of the Solar system, and of the planets of TRAPPIST-1. The TRAPPIST-1 star is small, barely bigger than Jupiter. The planets of TRAPPIST-1 are comparable to Earth. Original Image
Credit: Amanda Smith/IoA

Diagram showing the sizes of the TRAPPIST-1 star and planets, compared to objects in our own solar system. The star TRAPPIST-1 is only slightly bigger than Jupiter.

Energy Fluxes in TRAPPIST-1 System

Comparing the TRAPPIST-1 system with the Solar System. Here the vertical axis represents the amount of energy received from the star, for Earth = 1. Numbers indicate how much flux (2=twice more, ½ = half) a certain distance corresponds. Sizes of the planets are all relative to each other. Original Image
Credit: Amanda Smith/IoA

Diagram showing how much stellar energy the TRAPPIST-1 planets receive, compared to worlds in our own solar system.

TRAPPIST-1 System from Above

View of the planetary system from above. The star is at the centre and the planets are in orbit around it. Their relative position corresponds to what the system would have looked like when we saw the first planet pass in front of the star. The relative sizes of the planets are correct, but on a different scale to their distance to the star. Original Image
Credit: Amanda Smith/IoA

The orbits of the seven TRAPPIST-1 planets. The relative sizes of the planets are correct, but on a different scale to their distance to the star.

Planet Orbits Around TRAPPIST-1

Data on the discovery of seven planets around the star TRAPPIST-1. Original Image
Credit: ESO/M. Gillon et al.

This diagram shows the orbits of seven planets around the cool red dwarf star, TRAPPIST-1. The shaded area shows the star's "habitable zone," where a planet could have the right surface temperature for liquid water. The dotted lines show alternative boundaries to the habitable zone based on different "theoretical assumptions," according to a statement from the European Southern Observatory.

Planetary Transit of TRAPPIST-1

Data on the discovery of seven planets around the star TRAPPIST-1. Original Image
Credit: ESO/M. Gillon et al.

This chart shows how the red dwarf star TRAPPIST-1 appears to grow slightly dimmer each time one of its seven known planets crosses in front of the star )as seen from Earth).

Triple Transit

Data on the discovery of seven planets around the star TRAPPIST-1. Original Image
Credit: ESO/M. Gillon et al.

This graph shows the star TRAPPIST-1 during a rare triple transit event. A planetary transit occurs when a planet passes between its parent star and the Earth, causing an apparent change in the star's brightness. In this case, three planets transited the star.

TRAPPIST-1 Brightness Profile

Data on the discovery of seven planets around the star TRAPPIST-1. Original Image
Credit: ESO/M. Gillon et al.

This diagram shows the brightness of the cool red dwarf star TRAPPIST-1 over 20 days. Dips in the brightness are caused by one or more planets orbiting in front of the star and briefly blocking its light.

TRAPPIST-1 Star v Sun

This artist's impression shows the size of Earth's sun compared to the cool red dwarf star TRAPPIST-1. Planets that orbit closer to the star than Mercury orbits the sun can still have surface temperatures cool enough to support liquid water. Original Image
Credit: ESO

This artist's impression shows the size of Earth's sun compared to the cool red dwarf star TRAPPIST-1. Planets that orbit closer to the star than Mercury orbits the sun can still have surface temperatures cool enough to support liquid water.

TRAPPIST-1 Solar System Comparison

This diagram compares the TRAPPIST-1 planet system with Earth's solar system. The size of Earth's sun is shown with regard to the red dwarf star, TRAPPIST-1. The position of the seven planets around TRAPPIST-1 are shown in relation to Mercury's orbit around the sun. Original Image
Credit: ESO/O. Furtak

This diagram compares the TRAPPIST-1 planet system with Earth's solar system. The size of Earth's sun is shown with regard to the red dwarf star, TRAPPIST-1. The position of the seven planets around TRAPPIST-1 are shown in relation to Mercury's orbit around the sun.

TRAPPIST-1 Size Comparison

Diagrams of the TRAPPIST-1 system compared to Earth's solar system. Original Image
Credit: ESO/O. Furtak

A size comparison of the TRAPPIST-1 system with the sun and the inner-most planets, as well as Jupiter and its largest moons.

TRAPPIST-1 and Galilean Moons

Diagrams of the TRAPPIST-1 system compared to Earth's solar system. Original Image
Credit: ESO/O. Furtak

This diagram compares the TRAPPIST-1 system to the orbits of some of Jupiter's largest moons.

A Distant View in TRAPPIST-1

An artist's impression of the view from a planet in the TRAPPIST-1 system. Original Image
Credit: ESO/M. Kornmesser/<a href="http://www.spaceengine.org/">spaceengine.org</a>

An artist's impression of what an observer might see standing on one of the more distant planets known to orbit the cool dwarf star TRAPPIST-1.

A View from TRAPPIST-1

An artist's impression of the view from a planet in the TRAPPIST-1 system. Original Image
Credit: ESO/M. Kornmesser/<a href="http://www.spaceengine.org/">spaceengine.org</a>

An artist's impression of what it might look like from the surface of a planet in the TRAPPIST-1 system.

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