An international team of astronomers has released the largest ever compilation of exoplanet-detecting observations made using a technique called the radial velocity method. By making the data public, the team is offering unprecedented access to one of the best exoplanet searches in the world.
UCSC astronomer Steve Vogt (foreground) with collaborator Paul Butler at the W. M. Keck Observatory in Hawaii. Photo by Laurie HatchThe data were gathered as part of a two-decade planet-hunting program using a spectrometer called HIRES, built by UC Santa Cruz astronomer Steven Vogt and mounted on the 10-meter Keck-I telescope at the W. M. Keck Observatory atop Mauna Kea in Hawaii.
“HIRES was not specifically optimized to do this type of exoplanet detective work, but has turned out to be a workhorse instrument of the field,” said Vogt, a professor emeritus of astronomy and astrophysics. “I am very happy to contribute to science that is fundamentally changing how we view ourselves in the universe.”
Many scientists believe the Earth was dry when it first formed, and that the building blocks for life on our planet — carbon, nitrogen and water — appeared only later as a result of collisions with other objects in our solar system that had those elements.
The twin domes of Keck Observatory lit by the first rays of dawnToday, a UCLA-led team of scientists reports that it has discovered the existence of a white dwarf star whose atmosphere is rich in carbon and nitrogen, as well as in oxygen and hydrogen, the components of water. The white dwarf is approximately 200 light years from Earth and is located in the constellation Boötes.
HIRES instrument helps detect potential exoplanets. Artist’s conceptions of the probable planet orbiting a star called GJ 411, courtesy of Ricardo Ramirez.An international team of astronomers today released a compilation of almost 61,000 individual measurements made on more than 1,600 stars, used to detect exoplanets elsewhere in our Milky Way galaxy. The compilation includes data on over 100 new potential exoplanets. The entire dataset was observed using one of the twin telescopes of the W. M. Keck Observatory on Maunakea over the past two decades. The search for new worlds elsewhere in our Milky Way galaxy is one of the most exciting frontiers in astronomy today. The paper is published in the Astronomical Journal.
A new device on the W.M. Keck Observatory in Hawaii has delivered its first images, showing a ring of planet-forming dust around a star, and separately, a cool, star-like body, called a brown dwarf, lying near its companion star.
The vortex mask with a microscopic view shown on the right. Image Credit: University of Liège/Uppsala UniversityThe device, called a vortex coronagraph, was recently installed inside NIRC2 (Near Infrared Camera 2), the workhorse infrared imaging camera at Keck. It has the potential to image planetary systems and brown dwarfs closer to their host stars than any other instrument in the world.
“The vortex coronagraph allows us to peer into the regions around stars where giant planets like Jupiter and Saturn supposedly form,” said Dmitri Mawet, research scientist at NASA’s Jet Propulsion Laboratory and Caltech, both in Pasadena. “Before now, we were only able to image gas giants that are born much farther out. With the vortex, we will be able to see planets orbiting as close to their stars as Jupiter is to our sun, or about two to three times closer than what was possible before.”
Astronomers have just made a new measurement of the Hubble constant, the rate at which the universe is expanding, and it doesn’t quite line up with a different estimate of the same number. That discrepancy could hint at “new physics” beyond the standard model of cosmology, according to the team, which includes physicists from the University of California, Davis, that made the observation.
The image of this quasar is split into four by a massive galaxy acting as a gravitational lens. Image credit: Sherry Suyu, European Space Agency/Hubble Space Telescope/NASAThe Hubble constant allows astronomers to measure the scale and age of the universe and measure the distance to the most remote objects we can see, said Chris Fassnacht, a physics professor at UC Davis and a member of the international H0LiCOW (H0 Lenses in COSMOGRAIL’s Wellspring) collaboration, which carried out the work.
Led by Sherry Suyu at the Max Planck Institute for Astrophysics in Germany, the H0LICOW team used the NASA/ESA Hubble Space Telescope and other space- and Earth-based telescopes, including the Keck telescopes in Hawaii, to observe three galaxies and arrive at an independent measurement of the Hubble constant. Eduard Rusu, a postdoctoral researcher at UC Davis, is first author on one of five papers describing the work, due to be published in the Monthly Notices of the Royal Astronomical Society.
Keck Observatory is pushing the cutting edge of scientific discovery with the addition of the world’s most sensitive instrument for measuring the tendrils of faint gas in the intergalactic medium known as the cosmic web. The 5-ton instrument, the size of an ice cream truck, is named the Keck Cosmic Web Imager (KCWI). KCWI will uncover vital clues about the life-cycle of galaxies, helping to unravel mysteries about our universe.
KCWI being lifted off the trailer at Keck Observatory on the summit of Mauna Kea, Jan 20, 2017Physics professor, Christopher Martin, and his team at Caltech, in collaboration with Keck Observatory, University of California Santa Cruz and industrial partners, designed and built the spectrograph to study the cosmic web in unprecedented detail. KCWI will enable astronomers to study many other exceedingly faint objects in the universe as well.
“For decades, astronomers have demonstrated that galaxies evolve. Now, we’re trying to figure out how and why,” says Martin, describing the potential of this instrument. “We know the gas around galaxies is ultimately fueling them, but it is so faint – we still haven’t been able to get a close look at it and understand how this process works.”
The design of KCWI is based on its predecessor, the Palomar Cosmic Web Imager. KCWI will be installed on one of the twin 10-meter Keck Observatory telescopes, the largest optical/infrared telescopes in the world. The telescopes’ location on Maunakea provides the most pristine viewing conditions in the world for this science. This unbeatable combination of technology and location will enable KCWI to provide some of the most-detailed glimpses of the universe ever, including the study of gas jets around young stars, the winds of dead stars and even supermassive black holes.
“The best location in the world for astronomy calls for the best tools for astronomy,” said Hilton Lewis, director of the Keck Observatory. “With KCWI on the world’s largest telescope, we are well positioned to develop our understanding of the evolution of galaxies by capturing high-resolution spectra of some of the faintest, most difficult to study objects in the universe in ways never before possible.”
KCWI arrived by ship from Los Angeles on January 20 and was carefully transported up to the observatory atop Maunakea. The instrument will be installed and tested, followed by the first observations in the coming months.
The overlaid curve in depicts the inferred cyclic change in velocities in one such system, called KIC 9965691, looking something like the graph of an electrocardiogram. Credits: NASA/JPL-CaltechMatters of the heart can be puzzling and mysterious — so too with unusual astronomical objects called heartbeat stars.
Heartbeat stars, discovered in large numbers by NASA’s Kepler space telescope, are binary stars (systems of two stars orbiting each other) that got their name because if you were to map out their brightness over time, the result would look like an electrocardiogram, a graph of the electrical activity of the heart. Scientists are interested in them because they are binary systems in elongated elliptical orbits. This makes them natural laboratories for studying the gravitational effects of stars on each other.
In a heartbeat star system, the distance between the two stars varies drastically as they orbit each other. Heartbeat stars can get as close as a few stellar radii to each other, and as far as 10 times that distance during the course of one orbit.
A NIRC2 image of Jupiter’s Moon IoJupiter’s moon Io continues to be the most volcanically active body in the solar system, as documented by the longest series of frequent, high-resolution observations of the moon’s thermal emission ever obtained.
Using near-infrared adaptive optics on two of the world’s largest telescopes — the 10-meter Keck II and the 8-meter Gemini North, both located near the summit of the dormant volcano Maunakea in Hawaii — UC Berkeley astronomers tracked 48 volcanic hot spots on the surface over a period of 29 months from August 2013 through the end of 2015.
“On a given night, we may see half a dozen or more different hot spots,” said Katherine de Kleer, a UC Berkeley graduate student who led the observations. “Of Io’s hundreds of active volcanoes, we have been able to track the 50 that were the most powerful over the past few years.”
Using the world’s most powerful telescopes, an international team of astronomers has discovered a massive galaxy that consists almost entirely of Dark Matter. Using the W. M. Keck Observatory and the Gemini North telescope – both on Maunakea, Hawaii – the team found a galaxy whose mass is almost entirely Dark Matter. The findings are being published in The Astrophysical Journal Letters today.
The dark galaxy Dragonfly 44. Credit: Pieter Van Dokkum, Roberto Abraham Gemini, Sloan Digital Sky SurveyEven though it is relatively nearby, the galaxy, named Dragonfly 44, had been missed by astronomers for decades because it is very dim. It was discovered just last year when the Dragonfly Telephoto Array observed a region of the sky in the constellation Coma. Upon further scrutiny, the team realized the galaxy had to have more than meets the eye: it has so few stars that it quickly would be ripped apart unless something was holding it together.
To determine the amount of Dark Matter in Dragonfly 44, astronomers used the DEIMOS instrument installed on Keck II to measure the velocities of stars for 33.5 hours over a period of six nights so they could determine the galaxy’s mass. The team then used the Gemini Multi-Object Spectrograph (GMOS) on the 8-meter Gemini North telescope on Maunakea in Hawaii to reveal a halo of spherical clusters of stars around the galaxy’s core, similar to the halo that surrounds our Milky Way Galaxy.
Massive galaxy cluster MACS J0416 seen in X-rays (blue), visible light (red, green, and blue), and radio light (pink). Credit: NASA, CXC, SAO, G.Ogrean, STSCI, NRAO, AUI, NSFThe international University of California, Riverside-led SpARCS collaboration has discovered four of the most distant clusters of galaxies ever found, as they appeared when the Universe was only four billion years old. Clusters are rare regions of the Universe consisting of hundreds of galaxies containing trillions of stars, as well as hot gas and mysterious Dark Matter. Spectroscopic observations from the W. M. Keck Observatory on Maunakea, Hawaii and the Very Large Telescope in Chile confirmed the four candidates to be massive clusters. This sample is now providing the best measurement yet of when and how fast galaxy clusters stop forming stars in the early Universe.
“We looked at how the properties of galaxies in these clusters differed from galaxies found in more typical environments with fewer close neighbors,” said lead author Julie Nantais, an assistant professor at the Andres Bello University in Chile. “It has long been known that when a galaxy falls into a cluster, interactions with other cluster galaxies and with hot gas accelerate the shut off of its star formation relative to that of a similar galaxy in the field, in a process known as environmental quenching. The SpARCS team have developed new techniques using Spitzer Space Telescope infrared observations to identify hundreds of previously-undiscovered clusters of galaxies in the distant Universe.”
