Eric L. N. Jensen Astronomy Research and Teaching
		HK Tau velocity data from ALMA (Jensen & Akeson 2014, Nature)	HK Tau, artist's conception (©2014 Robert Hurt)

I'm a Professor of Astronomy in the Physics and Astronomy Department at Swarthmore College. I also teach about climate change in Swarthmore's Environmental Studies program, and I'm former Director of the Frank Aydelotte Foundation for the Advancement of the Liberal Arts.

My research interest, broadly speaking, is understanding extrasolar planets, planets that orbit other stars. I'm also interested in astrobiology, the study of the origin and distribution of life in the cosmos. This page gives a short introduction to what I do.

Astronomy Research

• Publications of my research (NASA ADS or orcid.org), and a current CV.

• One of the things I study is protoplanetary disks around young binary stars. I'm interested in planet formation in binary systems, and whether such planets would be habitable. Since more than half of all stars are members of binary systems, understanding how often planets form in binaries is important for understanding the frequency of planet formation in the universe and the likelihood of life outside our solar system.

  One project related to this topic is observations of disks around HK Tau, a young binary system where we can see that the two protoplanetary disks around the stars are significantly misaligned with each other (see images above, and National Geographic story). This means that any planets that form in this system will likely have orbits that oscillate in inclination and eccentricity due to the influence of the binary companion star. This is one example of how ALMA, a new array of millimeter telescope in Chile, is allowing my collaborators and I to make much more sensitive observations of these disks than we were able to in the past.

• I work with the Kilodegree Extremely Little Telescope (KELT) survey for extrasolar planets. My students and I use the Peter van de Kamp Observatory here at Swarthmore to search for transits (small eclipses) that occur when planets pass in front of their host stars. These transits not only reveal that a planet orbits that star, but the depth of the eclipse allows us to determine the planet's radius. Here's a story about the first two planets discovered by the survey.

  I wrote Tapir, some software to help plan astronomical observations, in support of this project and have released the source code to the community.

• I have also studied young, nearby stars. In the last few years, astronomers have discovered a number of relatively young (only about 10 million years old!) stars that are quite nearby (only about 150 light years). These stars are difficult to find because they are not associated with large clouds of gas and dust, as is common for younger stars. These stars are of interest because their proximity to Earth and their youth make them good targets for observing planet formation, and possibly for imaging the planets themselves.

• I'm interested in life beyond Earth, and along with my colleague Amy Cheng Vollmer, Professor of Biology, I've given some talks about some basic astrobiology concepts. Here's a lecture we gave on this topic.

• Want to get an idea of what life as a research astronomer is like? Here's a travelogue of an observing trip I took to the James Clerk Maxwell Telescope on Mauna Kea in Hawaii in September 1998.

Astronomy Teaching

Increasingly, I've been using Blackboard or Moodle as the course web page for courses I'm teaching.  One downside of that is the difficulty of linking to those courses so that people other than the students can see what I'm doing.  Below are links to a few course pages that should be accessible (though in some cases they link to more recent iterations of the courses, taught by other people).

• Astronomy 121, Research Techniques in Observational Astronomy (a junior/senior level seminar on practical aspects of doing astronomy research, including on-line resources, coordinate systems, detectors, data analysis, and observing in different parts of the electromagnetic spectrum).

• Astronomy 16, Modern Astrophysics, a calculus-based introductory astrophysics course for prospective astronomy and astrophysics majors or minors (and anyone else who is interested in astronomy and has a little physics and calculus under his/her belt!).
• Astronomy 1, Introduction to Astronomy, a general survey of astronomy.

Comments or suggestions to Eric Jensen,

Last modified: Wed Jul 24 13:41:52 EDT 2019