Derek is the Principal Investigator on a successful proposal for a design study for a small NASA satellite to study oscillations in massive stars. The baseline mission includes a 75mm refractive camera feeding detectors in both NUV and visible wavelengths. Detectors are photon-counting sealed-tube micro-channel plates combined with onboard preprocessing to limit the required data rate. The mission would observe roughly 6 Milky Way fields over a 2-year period.

  • Wide Binaries and Gyrochronology

    We are using “wide binaries” to test models for gyrochronology, the idea that the stellar rotation rate can be used as a proxy for stellar age. In such wide binaries, the two components don’t interact with one another, and thus if gyrochronology works both should show the same rotationally-determined age. We are collaborating with Terry Oswalt, Tomomi Otani, and Ted Von Hipple (Embry-Riddle Aeronautical University) to carry out this project using K2 and TESS data, and the FGCU team has developed a tool for measuring rotation periods based on light curves using a variety of different methods.

  • Developing a publicly-accessible pipeline and data products for the TESS full-frame images

    Derek serves as co-chair of the TESS Asteroseismic Consortium (TASC) international effort to produce TESS light curves for the millions of stars which will appear in the full-frame images observed by the spacecraft.

  • Finding Gamma-Ray Burst (GRB) precursors in the TESS fields

    GRBs are the most luminous events in the universe, and are believed to represent the coalescence of a binary neutron star or the collapse of a single neutron star into a black hole. Choosing between the various models for the event would be made easier if we could detect such a system prior to the actual GRB event, and we are searching the TESS images of the full sky to find any such precursors.

  • Solar Analogs

    We are nearing completion of a long-term study measuring rotation periods and spot coverage for all of the solar analog candidates in the K2 fields, using (and comparing) multiple approaches for the analysis. We are also conducting uniform high-resolution spectroscopy of our candidate stars using the 3.5m telescope at Apache Point, NM, in order to better characterize them and examining X-ray and UV emission from our target stars. In the last year, we have broadened the project to include analysis of TESS solar analogs/twins with asteroseismic detections, in order to test rotational evolution models.

  • Asteroseismology

    We are using TESS to do asteroseismology and modeling of massive main sequence stars. I am also working on a number of projects combining asteroseismic analysis of exoplanet host stars with transit modeling, as well as lower main sequence stars with known rotation periods. I have developed an algorithm for producing light curves from the TESS observations which can have noise levels as much as 20% less than the standard product and am supplying these to a number of studies.

  • Polarimetry

    Together with Daniel Cotton and Jeremy Bailey (Australian National University and University of New South Wales) and Conny Aerts (KU Leuven), we have been using the new HIPPI-2 polarimeter on the AAT 4-meter telescope to attempt to detect polarimetric signatures in classical pulsating stars. We then combine these data with ground-based radial-velocity spectroscopy, TESS photometry, and archival WIRE photometry to identify oscillation modes.

  • Modeling rotational evolution of lower-main sequence stars

    We continue to examine the impact of changing magnetic field morphology on the efficiency of angular momentum loss rates. Our particular interest is to understand the impact of Coriolis-induced deflection of rising magnetic flux tubes on the resulting coronal field morphology and hence the rotational evolution of the stars.

  • Active Binary Stars

    Derek is using the TESS data to examine about 100 active binary stars of the RS CVn and BY Dra type. These are close binaries which, because of their interaction, don’t spindown with time the way single stars do, and thus serve as laboratories for stellar activity such as spots and flares. This work is a collaboration with Harold Nations (College of Southern Nevada) and Heather Preston (Calusa Nature Center).

  • Instrumentation

    Derek delivered a fiber-fed astronomical spectrograph for use on the Apache Point Observatory 0.5m telescope, and we have successfully installed and tested the instrument. Final checkout has been delayed due to COVID, but we anticipate the spectrograph becoming available as a facility instrument this fall. We are renovating the FGCU 0.4-meter telescope for use as an instrument testbed, and plan to use it with a high-speed camera for exoplanet imagining and with an ultra-high-resolution fiber spectrograph (using virtual phased array technology) prior to hosting that instrument on a larger telescope at a better site. The upgrades to the observatory will also enable it to return to use as a public outreach site.