First Friday Astronomy – Summer 2026

Posted by admin on April 8, 2026
Posted in: First Friday Astronomy, Public Outreach. Tagged: .

Boise State’s First Friday Astronomy Event Schedule for Summer 2026. Our guests will be

  • May 1 – Dr. Ellie Hara, Postdoctoral Research Fellow, Rensselaer Polytechnic Institute – From Stardust to Cells: The Unsolved Mystery of Life’s Origin
  • Jun 5 – Dr. Racine Cleveland, Postdoctoral Research Fellow, Boise State University – Of Dunes and Ice: A Surface-Atmosphere Investigation on Planetary Bodies – racinecleveland.com
  • Jul 3 – Kirk Long, Ph.D. Candidate, University of Colorado Boulder – How to Weigh a Supermassive Black Hole: Insights From Quasars Across Cosmic Time
  • Aug 7 – Dr. Kathryn Gardner-Vandy, Associate Professor of Aviation & Space, Oklahoma State University – Meteorites: The Storytellers of our Solar System – experts.okstate.edu/kat.gardner-vandy

Metrics for Optimizing Searches for Orbital Precession and Tidal Decay via Transit- and Occultation-Timing

Posted by admin on January 21, 2026
Posted in: Research. Tagged: , , , .

Some planets in other solar systems orbit so close to their stars that they are spiral inward, ultimately to be ripped apart and eaten by their stars.

Looking for signs of that in-spiral, many astronomers, including students in my own research group, study transit signals — the shadows of planets as they pass in front of their host stars, as seen from Earth. For a planet spiral into its star, the time between one transit and the next will get shorter and shorter over many years. And so by measuring many transits, we can find signs of tidal in-spiral.

One big problem with looking for such tidally-driven signals is that other effects can also effect the time between transits, and so we need a good way to distinguish between these different effects.

In a recent paper from our group, we map out some ways to tell the difference between these different effects using tides. The bottom line: it’s not easy to tell the difference, but observations of exoplanet transits by citizen scientists can be a really important tool for the long-term monitoring required to find tidally decaying worlds that are not long for this world.

Related Publications

Tidal Evolution of Close-in Extrasolar Planets

Posted by admin on December 17, 2025
Posted in: Research. Tagged: , .

The distribution of orbital eccentricities e of extrasolar planets with semimajor axes a > 0.2 AU is very uniform, and values for e are relatively large, averaging 0.3 and broadly distributed up to near 1. For a < 0.2 AU, eccentricities are much smaller (most e < 0.2), a characteristic widely attributed to damping by tides after the planets formed and the protoplanetary gas disk dissipated. Most previous estimates of the tidal damping considered the tides raised on the planets, but ignored the tides raised on the stars. Perhaps most important, in many studies the strongly coupled evolution between e and a was ignored. In Jackson+ (2008a), my colleagues and I modeled the coupled tidal evolution of e and a for many extrasolar planets and confirmed that even close-in planets probably began with broadly distributed e-values, like those for planets far from their host stars and unaffected by tides. The accompanying evolution of a-values showed most close-in planets had significantly larger a at the start of tidal migration, and the current small values of a were only reached gradually due to tides over the ages of the planets.

Related Scientific Publications:

  • Jackson+ (2008a). “Tidal Evolution of Close-in Extrasolar Planets.” ApJ 678, 1396.
  • Jackson+ (2008). “Tidal evolution of close-in extra-solar planets.” Proceed. IAU 249, 187.