The star system harboring the new planet contains only one star, as do the other three systems with extrasolar planets analyzed by Kane, an assistant professor of physics and astronomy, and his colleagues. It is a surprising finding, given the high rate of multiple-star systems in our solar neighborhood.
"There is a great interest in these stars that are known to host planets," Kane explained, since astronomers suspect that planet formation in a multi-star system would be very different from planet formation in a single-star system like our own. Kane presented his findings today at the annual conference of the American Astronomical Society.
A multiple-star system "might have not one but two planetary disks" where planets form, he said. "Or it could be that having an extra star would be disruptive, and its gravity could cause any protoplanets to pull apart."
Relatively few extrasolar planets have been found in multiple-star systems, "but we know that they are there," Kane said.
In the four systems studied by the researchers, using optical imaging data collected at the Gemini North observatory in Hawaii, there were some intriguing signs that perhaps a second star -- or something else -- was present.
In each system, the extrasolar planets were discovered by the radial velocity technique, pioneered at SF State by astronomer Geoffrey Marcy, now at the University of California, Berkeley. The radial velocity technique measures variations in the speed at which a star moves away and toward Earth, perturbed or "wobbled" by the gravitational pull of a nearby cosmic body. Depending on the radial velocity signature, astronomers can calculate whether the wobble is coming from a planet or star.
In the star systems studied by Kane and his colleagues, there was a part of the radial velocity data that couldn't be explained entirely by the pull of an orbiting planet. And at the same time, the planets that had already been discovered in these systems followed eccentric orbits, swinging away from their stars in a less circular and more elliptical fashion, "more like that of a comet," Kane said.
With these two clues, the researchers wondered if the radial velocity and eccentric orbits might be explained by the presence of another star in the system. But when they took a closer look at the systems, they were able to rule out the possibility that another star was perturbing the system.
"I thought we were likely to find stellar companions, and when all four didn't have a binary star, that did surprise me," Kane said.
But in the case of one star, Pisces' HD 4230, the unexplained radial velocity appears to be coming from the pull of a previously undiscovered giant planet, the researchers report. They confirmed the planet's presence with additional radial velocity data collected at Hawaii's Keck observatory.
Given that the researchers did not find any stellar companions, Kane says it is very likely that the leftover radial velocity is instead a signal that there are additional planets to be found in all four systems. The researchers feel this is especially true for the system called HD 168443, where their ability to detect a companion star was very strong.
Kane is one of the few astronomers to use a variety of planet-hunting techniques, including radial velocity and imaging. He said that the new findings had motivated him to look at other extrasolar systems with similar kinds of unexplained radial velocity data, to see if other stars or planets may be lurking there.
"Limits on Stellar Companions to Exoplanet Host Stars with Eccentric Planets" is in press at Astrophysical Journal. Kane co-authored the study with SF State Postdoctoral Fellow Natalie R. Hinkel; Steve B. Howell of NASA Ames Research Center; Elliott P. Horch of Southern Connecticut State University; Ying Feng and Jason T. Wright of Pennsylvania State University; David R. Ciardi of NASA Exoplanet Science Institute; Mark E. Everett of National Optical Astronomy Observatory and Andrew W. Howard of the University of Hawaii.
SF State is the only master's level public university serving the counties of San Francisco, San Mateo and Marin. The university enrolls more than 30,000 students each year. With nationally acclaimed programs in a range of fields -- from creative writing, cinema and biology to history, broadcast and electronic communications arts, theatre arts and ethnic studies -- the University's more than 219,000 graduates have contributed to the economic cultural and civic fabric of San Francisco and beyond.
Nan Broadbent | EurekAlert!
Donuts, math, and superdense teleportation of quantum information
29.05.2015 | University of Illinois College of Engineering
Physicists precisely measure interaction between atoms and carbon surfaces
29.05.2015 | University of Washington
Many joining and cutting processes are possible only with lasers. New technologies make it possible to manufacture metal components with hollow structures that are significantly lighter and yet just as stable as solid components. In addition, lasers can be used to combine various lightweight construction materials and steels with each other. The Fraunhofer Institute for Laser Technology ILT in Aachen is presenting a range of such solutions at the LASER World of Photonics trade fair from June 22 to 25, 2015 in Munich, Germany, (Hall A3, Stand 121).
Lightweight construction materials are popular: aluminum is used in the bodywork of cars, for example, and aircraft fuselages already consist in large part of...
Using ultrashort laser pulses, scientists in Max Planck Institute of Quantum Optics have demonstrated the emission of extreme ultraviolet radiation from thin dielectric films and have investigated the underlying mechanisms.
In 1961, only shortly after the invention of the first laser, scientists exposed silicon dioxide crystals (also known as quartz) to an intense ruby laser to...
The only professorship in Germany to date, one master's programme, one laboratory with worldwide unique equipment and the corresponding research results: The University of Würzburg is leading in the field of biofabrication.
Paul Dalton is presently the only professor of biofabrication in Germany. About a year ago, the Australian researcher relocated to the Würzburg department for...
Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.
Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...
Development and implementation of an advanced automobile parking navigation platform for parking services
To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...
20.05.2015 | Event News
18.05.2015 | Event News
12.05.2015 | Event News
29.05.2015 | Life Sciences
29.05.2015 | Earth Sciences
29.05.2015 | Physics and Astronomy