Hannah Diamond-Lowe, PhD

I study the atmospheres of small planets orbiting M stars.

About Me

I am a postdoctoral researcher at the National Space Institute, Technical University of Denmark (DTU Space) where I work in the Exoplanet Group. I characterize small exoplanet atmospheres with ground- and space-based observatories.

My Work

My research focuses on investigating the atmospheres of (mostly) terrestrial exoplanets.

Space-based ultraviolet spectrum of the mid-M dwarf LHS 3844

LHS 3844 is a mid-M dwarf that hosts the highly irradiated terrestrial exoplanet, LHS 3844b. Using the Hubble Space Telescope and Cosmic Origins Spectrograph we captured an ultraviolet spectrum of this nearby star. We detected a single flare in the far UV (shown here). Understanding the high-energy output of stars allows us to better understand the atmospheres (or lack thereof) of the planets that orbit them. We will present a panchromatic spectrum from 1 to 105 Angstroms in an upcoming paper. Stay tuned!

Ground-based transmission spectroscopy of LHS 3844b with 13 transits

LHS 3844b is a highly irradiated terrestrial world orbiting a mid-M dwarf star. 100 hours of Spitzer data ruled out the presence of high mean molecular weight atmospheres of 10 bars or higher surface pressures (Kreidberg, et al. 2019). In this work we rule out low mean molecular weight atmospheres at surface pressures of 0.1 bars and greater, providing further evidence that LHS 3844b is likely a bare rock.
Diamond-Lowe, et al. 2020b

Simultaneous ground-based transmission spectroscopy of LHS 1140b with Magellan I & II

LHS 1140b is a terrestrial exoplanet orbiting in the habitable zone around an M4.5 star 15 parsecs away. This planet has a 25-day orbital period and a 2-hour transit duration. As such is it difficult to observe transits of LHS 1140b from the ground. We captured two transits of LHS 1140b simultaneously with the twin Magellan telescopes at Las Campanas Observatory in Chile. We share the results and explain the process of multi-object spectroscopy for exoplanet atmospheres.
Diamond-Lowe, et al. 2020a

Ground-based transmission spectroscopy of GJ 1132b

GJ 1132b is a terrestrial exoplanet orbiting an M4.5 star 12 parsecs away. With a radius of 1.2 Earth radii and a mass of 1.6 Earth masses, this world is a rocky one. GJ 1132b orbits close to its host star and receives 19 times Earth's insolation, meaning that though this world has a solid surface, it is too hot to support liquid water and too irradiated to support life. We observed five transits of GJ 1132b with the Magellan Clay telescope and the LDSS3C spectrograph at Las Campanas Observatory in Chile. The transmission spectrum we construct from a joint fit to all of our spectro-photometric data disfavors a clear, 10x solar metallicity atmosphere at 3.7σ confidence and a 10% H2O, 90% H2 atmosphere at 3.5σ confidence. The data are consistent with a featureless spectrum, implying that GJ 1132b has a high mean molecular weight atmosphere or no atmosphere at all.
Diamond-Lowe, et al. 2018

No thermal inversion in the atmosphere of HD 209458b

This archetypal hot Jupiter was once thought to have a thermal inversion in its upper atmosphere. We analyze secondary eclipses of this planet taken with the Spitzer Space Telescope in four photometric bandpasses. Our self-consistent analysis with the state-of-the-art POET pipeline, along with an atmospheric retrieval, reveals that this hot Jupiter is more consistent with a black body and does not host a thermal inversion. These results were corroborated with HST/WFC3 observations.
Diamond-Lowe, et al. 2014
Line, et al. 2016

Click here for my public outreach talk: Worlds around other stars: the past, present, and future of exoplanets


  • Address

    DTU Space
    Elektrovej 328
    DK-2800 Kgs. Lyngby
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