Skygazers at northern latitudes are familiar with the W-shaped star pattern of Cassiopeia the Queen. This circumpolar constellation is visible year-round near the North Star. Tucked next to one leg of the W lies a modest 5th-magnitude star named HD 219134 that has been hiding a secret.
Astronomers have now teased out that secret: a planet in a 3-day orbit that transits, or crosses in front of its star. At a distance of just 21 light-years, it is by far the closest transiting planet to Earth, which makes it ideal for follow-up studies. Moreover, it is the nearest rocky planet confirmed outside our solar system. Its host star is visible to the unaided eye from dark skies, meaning anyone with a good star map can see this record-breaking system.
This artist's rendition shows one possible appearance for the planet HD 219134b, the nearest rocky exoplanet found to date outside our solar system. The planet is 1.6 times the size of Earth, and whips around its star in just three days. Scientists predict that the scorching-hot planet -- known to be rocky through measurements of its mass and size -- would have a rocky, partially molten surface with geological activity, including possibly volcanoes.
"Most of the known planets are hundreds of light-years away. This one is practically a next-door neighbor," said astronomer Lars A. Buchhave of the Harvard-Smithsonian Center for Astrophysics (CfA).
"Its proximity makes HD 219134 ideal for future studies. The James Webb Space Telescope and future large ground-based observatories are sure to point at it and examine it in detail," said lead author Ati Motalebi of the Geneva Observatory.
The newfound world, designated HD 219134b, was discovered using the HARPS-North instrument on the 3.6-meter Telescopio Nazionale Galileo in the Canary Islands. The CfA is a major partner with the Geneva Observatory on the HARPS-North Collaboration, which includes several other European partners.
HARPS-North detects planets using the radial velocity method, which allows astronomers to measure a planet's mass. HD 219134b weighs 4.5 times the mass of Earth, making it a super-Earth.
With such a close orbit, researchers realized that there was good possibility the planet would transit its star. In April of this year they targeted the system with NASA's Spitzer Space Telescope. At the appropriate time, the star dimmed slightly as the planet crossed the star's face. Measuring the depth of the transit gave the planet's size, which is 1.6 times Earth. As a result, the team can calculate the planet's density, which works out to about 6 g/cm3. This shows that HD 219134b is a rocky world.
But wait, there's more! The team detected three additional planets in the system using radial velocity data. A planet weighing at least 2.7 times Earth orbits the star once every 6.8 days. A Neptune-like planet with 9 times the mass of Earth circles in a 47-day orbit. And much further out, a hefty fourth world 62 times Earth's mass orbits at a distance of 2.1 astronomical units (200 million miles) with a "year" of 1,190 days. Any of these planets might also transit the star, so the team plans to search for additional transits in the months ahead.
HD 219134 is an orange Type K star somewhat cooler, smaller and less massive than our Sun. Its key measurements have been pinned down very precisely, which thus allows a more precise determination of the properties of its accompanying planets.
This discovery came from the HARPS-North Rocky Planet Search, a dedicated survey examining about 50 nearby stars for signs of small planets. The team targeted nearby stars because those stars are brighter, which makes follow-up studies easier. In particular, additional observations might allow the detection and analysis of planetary atmospheres.
HD 219134 was one of the closest stars in the sample, so it was particularly lucky to find that it hosts a transiting planet. This system now holds the record for the nearest transiting exoplanet. As such, it likely will be a favorite for researchers for years to come.
Christine Pulliam | EurekAlert!
NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center
Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses