Welcome to the Planetary Research Laboratory

The Planetary Research Laboratory (PRL) is hosted within the Earth Sciences Department at the University of California, Riverside. Our research involves students at both the undergraduate and graduate level and includes a combination of observational and theoretical programs.

News from the Lab

2017-11-16: A fascinating class of exoplanets are those that lie in eccentric orbits around their host star. However, what happens when the host star of the eccentric planet happens to be a highly-evolved giant star? Our new discovery of just such a system indicates that the orbits of many of these planets will likely decay with time, resulting in the planet being eaten by the star. The details of the planet discovery and its predicted fate are detailed in the article "The Pan-Pacific Planet Search. VII. The Most Eccentric Planet Orbiting a Giant Star", published in the Astronomical Journal.

2017-11-01: A new article published in Science magazine describes current progress towards finding potentially habitable exoplanets and how we might detect signatures of biological activity. The article includes a description of PRL work that uses data from the Earth Polychromatic Imaging Camera (EPIC) on board the Deep Space Climate Observatory (DSCOVR). These data are being used to simulate the Earth as an exoplanet and recovery key planetary properties, such as the albedo, obliquity, and rotation rate.

2017-09-26: It is well-known that it is the tilt of the Earth's rotational axis relative to the planet of the orbit (obliquity) that is the primary cause of the seasons. Orbital eccentricity can also play a significant role in driving seasonal changes, such as the case for Mars. A new paper published by our team in the Astronomical Journal, entitled "Obliquity and Eccentricity Constraints For Terrestrial Exoplanets", explores the regions of parameter space where the flux variations due to eccntricity and obliquity are equivalent to each other. These are applied to several of the known exoplanets that reside in the Habitable Zone of their host stars.

2017-08-01: I'm happy to report that the Planetary Research Laboratory has officially relocated to the Earth Sciences Department at the University of California, Riverside (UCR). The PRL researches matches seamlessly with the astrobiology work being undertaken within the UCR Astrobiology Center.

2017-01-13: It is often said amongst exoplanet hunters that one only knows the planet as well as one knows the star. One of the closest stars to the Earth is Wolf 1061, at a distance of only 14 light years. The star is host to three known planets and new research from the PRL, including student Miranda Waters, has provided accurate measurements of the star that allowed a detailed study of the planets to be conducted. The results reveal the true radius of the star, it's temperature and luminosity, and the stellar rotation period. The derived Habitable Zone of the system shows that the middle planet is new the inner edge and is likely a Venus analog rather than habitable, but dynamical simulations show that the planet also undergoes Milankovitch cycles on relatively short timescales. The publication is entitled "Characterization of the Wolf 1061 Planetary System" and is due to appear in the Astrophysical Journal.

2016-12-09: Recently, the exciting new of a terrestrial planet candidate orbiting Proxima Centauri swept through the exoplanet community. The planet was discovered using the radial velocity method and, at this time, is not known to transit. Since the true mass of the planet depends upon the unknown inclination, we conducted a study on the effects of inclination on the planetary properties and how current and future missions may be able to detect the signatures of those effects. The publication is entitled "On the Orbital Inclination of Proxima Centauri b" and the full results of the study are available here.

2016-08-31: A paper led by PRL graduate student Justin Wittrock has been accepted for publication in the Astronomical Journal. The paper is entitled "Stellar Companions to the Exoplanet Host Stars HD 2638 and HD 164509" and presents new results from a survey of exoplanet host stars using Gemini-North. The data reveal low-mass stellar companions to two known exoplanet host stars that place interesting constraints on planetary formation and evolution scenarios as well as the orbital dynamics of the systems. The full version of the publication is available here.

2016-06-17: PRL graduate student, Alma Ceja, has been awarded an ARCS Scholarship. The ARCS Foundation provides scholarships to exceptional students to provide them with the needed support to help them grow in their scientific careers. Alma is studying anthropogenic effects (such as temperature changes) on the physiology of marine invertebrates. In a broader context, we are using temperature variation models of exoplanets to study implications for the growth and decline of hypothetical biological populations. Congratulations Alma!

2016-06-13: We have announced the discovery of a new planet orbiting two stars using data from the Kepler mission. The planet has both the largest size and largest orbit of any "circumbinary" planet yet discovered. It also orbits within the Habitable Zone of the binary system, which could have positive habitability implications for exomoons associated with the giant planet. The results of this work have been accepted for publication in the Astrophysical Journal and are available here.

2016-06-03: Professor Stephen Kane delivered two astrobiology talks that were streamed live via the NASA Astrobiology Institute Seminar Series and are now available for public viewing. The talks were held in early May 2016 at the University of California, Riverside. The first was a public talk entitled "Mercury Transit & Beyond: Planetary Discoveries Inside and Outside Our Solar System". The second was a science colloquium entitled "Analyzing Alien Worlds: A Multidisciplinary Approach to Characterizing Exoplanets". Additionally, a recent talk by Professor Kane delivered at the Silicon Valley Astronomy Lecture Series is now available online, and is entitled "Finding a New Earth: Exoplanets and the Habitable Zone".

2016-03-30: Using the Spitzer Space Telescope, we have observed 55 Cancri e, a two Earth radii planet that completes an orbit around the host star every 18 hours. Our observations show that there is an extreme day-night temperature difference of 1,300 K, consistent with either a thick atmosphere of a planet that has had the atmosphere stripped away. Read the associated publication to learn more.

2015-11-27: One of the most curious exoplanet discoveries over the past two decades is that planets can have highly eccentric orbits just like a comet. We can now confirm that HD 20782 b, a planet about 50% more massive than Jupiter, is the most eccentric planet known with an eccentricity of 0.96! We additionally found evidence that the planet "lights up" as it makes its closest approach to the host star. Read the associated publication to learn more.

2015-10-20: A research paper by PRL student Colin Chandler has been accepted for publication by the Astronomical Journal and was also featured on the website of the American Astronomical Society. The paper presents a new target selection catalog designed for surveys that aim to probe the Habitable Zone of nearby/bright host stars. The paper is entitled "The Catalog of Earth-Like Exoplanet Survey TArgets (CELESTA): A Database of Habitable Zones around Nearby Stars" and is available here.

2014-09-10: How common are Venus analogs in planetary systems? To help answer this question, we a have developed the "Venus Zone" as a target selection tool for future characterization missions. Our results identify 43 planets in the Venus Zone and show that almost half of Sun-like stars could have Venus-like planets. Read the associated publication to learn more.

2014-03-24: The Habitable Zone Gallery has been updated with many new features, plot, search functions, and much more. The gallery now contains 1,418 planets in 855 planetary systems, with 53 planets spending 100% of their orbit in the Habitable Zone.

2013-05-28: Imagine the hostile surface conditions on a more massive version of the planet Venus. We show in a recent paper that Kepler-69c is far more likely to bear a Venusian than Earth environment and thus is highly unlikely to be habitable. The Venera landers would not have fared so well.