Astronomers report dwarf star with unexpectedly giant planet

An international team of astronomers discovered an exoplanet, called NGTS-1b, revolving around M-dwarf star NGTS-1, that the team said does not fit existing notions of how stars and planets form. NGTS-1b is a gas giant, similar to Jupiter and of comparable volume and mass, but its parent star is about half the diameter and mass of the Sun, making this the most massive planet orbiting an M-dwarf ever discovered.

HD 189733 has a Jupiter-class planet. This image is artwork. Image credit: NASA, ESA & G. Bacon (PD)

NGTS-1b, about 600 light years from the Earth, is so extremely close to its star that a revolution around its star takes only about 2.6 Earth days — 2.647298 ± 0.000020 — and its surface temperature is about 800 K.

The planet was discovered by observing periodic fluctuations in the star's apparent brightness as NGTS-1b passed in front of it. NGTS-1b's mass is less than Jupiter, about 0.812 MJ (mass of Jupiter), but it has greater volume, with radius about 1.33 RJ (radius of Jupiter).

The existing understanding of planetary formation, the team explained, says small stars can produce rocky planets but cannot not pull in enough mass for larger, gaseous ones like NGTS-1b.

Based on the observations, NGTS-1's radius is 0.573±0.077 R☉ (solar radius) and using that value, astronomers calculated its weight to be about 0.598 M☉ (solar mass).

The research team discovered NGTS-1b using the Next-Generation Transit Survey (NGTS), an array of telescopes physically located in Chile, which was designed to search for planets around bright stars. NGTS-1 is a relatively dim red M-dwarf, which are very common in the universe, of apparent magnitude 15.52 ± 0.08.

NGTS-1b was difficult to find, despite being a monster of a planet, because its parent star is small and faint. Small stars are actually the most common in the universe, so it is possible there are many of these giant planets waiting to found.

To date, scientists have discovered only three gas giants which revolves around M-dwarf stars. The other two are Kepler-45b and HATS-6b which have masses 0.505 MJ and 0.32 MJ respectively. (Wikinews)

YOU MAY ALSO LIKE

'Iceball' Planet Discovered Through Microlensing

Scientists have discovered a new planet with the mass of Earth, orbiting its star at the same distance that we orbit our sun. The planet is likely far too cold to be habitable for life as we know it, however, because its star is so faint.

ESA, NASA’s SOHO Sees Bright Sungrazer Comet

ESA and NASA’s Solar and Heliospheric Observatory, or SOHO, saw a bright comet plunge toward the sun at nearly 1.3 million miles per hour.

NASA Climate Modeling Suggests Venus May Have Been Habitable

Venus may have had a shallow liquid-water ocean and habitable surface temperatures for up to 2 billion years of its early history, according to computer modeling of the planet’s ancient climate by scientists at NASA’s Goddard Institute for Space Studies.

K2 Finds Dead Star Vaporizing a Mini 'Planet'

Scientists have uncovered strong evidence of a tiny, rocky object being torn apart as it spirals around a white dwarf star. This discovery validates a long-held theory that white dwarfs are capable of cannibalizing possible remnant planets that have survived within its solar system.

NASA Spacecraft Achieves Unprecedented Success Studying Mercury

After extraordinary science findings and technological innovations, a NASA spacecraft launched in 2004 to study Mercury will impact the planet’s surface, most likely on April 30, after it runs out of propellant.

The Strange Structures of the Saturn Nebula

The spectacular planetary nebula NGC 7009, or the Saturn Nebula, emerges from the darkness like a series of oddly-shaped bubbles, lit up in glorious pinks and blues.