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PDS 70
PDS 70 (V1032 Centauri) is a very young T Tauri star in the constellation Centaurus. Located 370 light-years (110 parsecs) from Earth, it has a mass of 0.76 M☉ and is approximately 5.4 million years old. The star has a protoplanetary disk containing two nascent exoplanets, named PDS 70b and PDS 70c, which have been directly imaged by the European Southern Observatory's Very Large Telescope, as well as a 3rd unconfirmed one. PDS 70b was the first confirmed protoplanet to be directly imaged.
The "PDS" in this star's name stands for Pico dos Dias Survey, a survey that looked for pre-main-sequence stars based on the star's infrared colors measured by the IRAS satellite. PDS 70 was identified as a T Tauri variable star in 1992, from these infrared colors. PDS 70's brightness varies quasi-periodically with an amplitude of a few hundredths of a magnitude in visible light. Measurements of the star's period in the astronomical literature are inconsistent, ranging from 3.007 days to 5.1 or 5.6 days.
The protoplanetary disk around PDS 70 was first hypothesized in 1992 and fully imaged in 2006 with phase-mask coronagraph on the VLT. The disk has a radius of approximately 140 au. In 2012 a large gap (~65 au) in the disk was discovered, which was thought to be caused by planetary formation.
The gap was later found to have multiple regions: large dust grains were absent out to 80 au, while small dust grains were only absent out to the previously-observed 65 au. There is an asymmetry in the overall shape of the gap; these factors indicate that there are likely multiple planets affecting the shape of the gap and the dust distribution.
The James Webb Space Telescope has been used to detect water vapor in the inner part of the disk, where terrestrial planets may be forming.
In results published in 2018, a planet in the disk, named PDS 70 b, was imaged with SPHERE planet imager at the Very Large Telescope (VLT). With a mass estimated to be a few times greater than Jupiter, the planet is thought to have a temperature of around 1,200 K (930 °C; 1,700 °F) and an atmosphere with clouds; its orbit has an approximate radius of 20.8 AU (3.11 billion kilometres), taking around 120 years for a revolution.
The emission spectrum of the planet PDS 70 b is gray and featureless, and no molecular species were detected by 2021.
A second planet, designated PDS 70 c, was discovered in 2019 using the VLT's MUSE integral field spectrograph. The planet orbits its host star at a distance of 34.3 AU (5.13 billion kilometres), farther away than PDS 70 b. PDS 70 c is in a near 1:2 orbital resonance with PDS 70 b, meaning that PDS 70 c completes nearly one revolution once every time PDS 70 b completes nearly two.
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PDS 70
PDS 70 (V1032 Centauri) is a very young T Tauri star in the constellation Centaurus. Located 370 light-years (110 parsecs) from Earth, it has a mass of 0.76 M☉ and is approximately 5.4 million years old. The star has a protoplanetary disk containing two nascent exoplanets, named PDS 70b and PDS 70c, which have been directly imaged by the European Southern Observatory's Very Large Telescope, as well as a 3rd unconfirmed one. PDS 70b was the first confirmed protoplanet to be directly imaged.
The "PDS" in this star's name stands for Pico dos Dias Survey, a survey that looked for pre-main-sequence stars based on the star's infrared colors measured by the IRAS satellite. PDS 70 was identified as a T Tauri variable star in 1992, from these infrared colors. PDS 70's brightness varies quasi-periodically with an amplitude of a few hundredths of a magnitude in visible light. Measurements of the star's period in the astronomical literature are inconsistent, ranging from 3.007 days to 5.1 or 5.6 days.
The protoplanetary disk around PDS 70 was first hypothesized in 1992 and fully imaged in 2006 with phase-mask coronagraph on the VLT. The disk has a radius of approximately 140 au. In 2012 a large gap (~65 au) in the disk was discovered, which was thought to be caused by planetary formation.
The gap was later found to have multiple regions: large dust grains were absent out to 80 au, while small dust grains were only absent out to the previously-observed 65 au. There is an asymmetry in the overall shape of the gap; these factors indicate that there are likely multiple planets affecting the shape of the gap and the dust distribution.
The James Webb Space Telescope has been used to detect water vapor in the inner part of the disk, where terrestrial planets may be forming.
In results published in 2018, a planet in the disk, named PDS 70 b, was imaged with SPHERE planet imager at the Very Large Telescope (VLT). With a mass estimated to be a few times greater than Jupiter, the planet is thought to have a temperature of around 1,200 K (930 °C; 1,700 °F) and an atmosphere with clouds; its orbit has an approximate radius of 20.8 AU (3.11 billion kilometres), taking around 120 years for a revolution.
The emission spectrum of the planet PDS 70 b is gray and featureless, and no molecular species were detected by 2021.
A second planet, designated PDS 70 c, was discovered in 2019 using the VLT's MUSE integral field spectrograph. The planet orbits its host star at a distance of 34.3 AU (5.13 billion kilometres), farther away than PDS 70 b. PDS 70 c is in a near 1:2 orbital resonance with PDS 70 b, meaning that PDS 70 c completes nearly one revolution once every time PDS 70 b completes nearly two.