Fri 20 Jun 11:30: Title to be confirmed
Abstract not available
- Speaker: Speaker to be confirmed
- Friday 20 June 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Jupiter’s Turbulent Atmosphere
JunoCam, the visible light imager aboard NASA’s Juno spacecraft, captured this view of Jupiter’s northern high latitudes during the spacecraft’s 69th flyby of the giant planet on Jan. 28, 2025. Jupiter’s belts and zones stand out in this enhanced color rendition, along with the turbulence along their edges caused by winds going in different directions.
The original JunoCam data used to produce this view was taken from an altitude of about 36,000 miles (58,000 kilometers) above Jupiter’s cloud tops. JunoCam’s raw images are available for the public to peruse and process into image products. Citizen scientist Jackie Branc processed the image.
Since Juno arrived at Jupiter in 2016, it has been probing beneath the dense, forbidding clouds encircling the giant planet – the first orbiter to peer so closely. It seeks answers to questions about the origin and evolution of Jupiter, our solar system, and giant planets across the cosmos.
Learn more about NASA citizen science.
Image credit: Image data: NASA/JPL-Caltech/SwRI/MSSS; Image processing: Jackie Branc (CC BY)
Scientists in a race to discover why the Universe exists
Alien megastructures would likely self-destruct before we spot them
Thu 15 May 11:00: LCLU Coffee - Ligia F Coelho on "the changing colours of our planet as a tool for ilfe detection on icy moons and exoplanets"
In Person
We cannot predict life. We can, instead, learn from Earth’s biodiversity and their varied molecular catalogue of markers of adaptability. Biopigments are widespread biomolecules that serve as powerful surface biomarkers of adaptability to extreme conditions on our planet. These molecules have distinct and unique spectral signatures providing a promising avenue for detecting extraterrestrial life. However, current surface models for other planets overlook Earth’s broader biodiversity. In the Solar System, current models struggle to constrain non-icy mysterious spots on the surface of the Jovian icy moon Europa for lack of matching reference spectra. In parallel, exoplanet surface models tend to overemphasize chlorophyll-based landscapes, often constrained by the assumption that photosynthesis requires visible light. This introduces unnecessary restrictions on atmospheric opacity and composition. In reality, Earth’s biosphere hosts a vast array of biopigments capable of harnessing energy across the UV to IR spectrum, driving diverse metabolisms, volatile byproducts, and environmental adaptations—many of which serve as analogues for targets to be studied with future telescopes and space missions. By integrating Earth’s biological and evolutionary diversity with astrophysical tools, I will present life-detection frameworks based on a broad spectral dataset. I will show how in situ reflectance data from Svalbard (Arctic) and Atacama Desert can help us correlate biosignatures with specific environments. These findings contribute to biologically informed planetary models, crucial for the next generation missions, including Extremely Large Telescopes (ELTs), the Habitable Worlds Observatory (HWO) and Large Interferometer For Exoplanets (LIFE), as well as NASA ’s Europa Clipper, ESA ’s Juice and Enceladus L4. These exciting new instruments will probe several planetary surfaces for a new biosphere where orange, yellow, or purple may be the new green.
- Speaker: Ligia F Coelho (Cornell Astronomy)
- Thursday 15 May 2025, 11:00-12:00
- Venue: Battcock, Room F17.
- Series: LCLU Coffee Meetings; organiser: Paul B. Rimmer.
Tue 20 May 13:00: Cosmology with the ACT DR6 data release
In March 2025, the Atacama Cosmology Telescope (ACT) released its last cosmological analysis along with a new cosmic microwave background (CMB) dataset. The sixth data release (DR6), including data collected from 2017 to 2022, covers 40% of the sky at arcminute resolution providing the most precise maps of CMB temperature and polarization. In this talk, I will give an overview of the challenges faced during the ACT DR6 analysis and describe its constraints on fundamental assumptions of the standard cosmological model and extensions to it.
- Speaker: Adrien La Posta (University of Oxford)
- Tuesday 20 May 2025, 13:00-14:00
- Venue: SPECIAL LOCATION - CMS, MR12, Pav. D basement.
- Series: Cosmology Lunch; organiser: Louis Legrand.
A Machine-Learning Compositional Study of Exoplanetary Material Accreted Onto Five Helium-Atmosphere White Dwarfs with $\texttt{cecilia}$
A Machine-Learning Compositional Study of Exoplanetary Material Accreted Onto Five Helium-Atmosphere White Dwarfs with $\texttt{cecilia}$
A Machine-Learning Compositional Study of Exoplanetary Material Accreted Onto Five Helium-Atmosphere White Dwarfs with $\texttt{cecilia}$
Thu 15 May 16:00: The different merger and evolutionary histories of the Milky Way and Andromeda (M31)
The Milky Way experienced a major satellite merger 10 Gyr ago which altered, but did not destroy, the early high-alpha disk and created both an accreted and an in situ inner halo. The low-alpha disk that formed subsequently became bar-unstable 8 Gyr ago, creating the b/p bulge that also contains the inner high-alpha disk stars. M31 experienced a similar major satellite merger 3 Gyr ago which greatly heated and mixed the pre-existing high-metallicity disk, and also caused a massive inflow of gas and the formation of a dynamically hot secondary inner disk. Such a merger is consistent with the wide-spread star formation event 2-4 Gyr ago seen in disk colour-magnitude diagrams, and with the major substructures and metal-rich stars in the inner halo of M31 , when comparing photometric and recent spectroscopic data with available models. The merged satellite must have had a broad metallicity distribution and would have been the third most massive galaxy in the Local Group before the merger.
- Speaker: Ortwin Gerhard, MPE (Garching)
- Thursday 15 May 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: .
Thu 15 May 16:00: The different merger and evolutionary histories of the Milky Way and Andromeda (M31)
The Milky Way experienced a major satellite merger 10 Gyr ago which altered, but did not destroy, the early high-alpha disk and created both an accreted and an in situ inner halo. The low-alpha disk that formed subsequently became bar-unstable 8 Gyr ago, creating the b/p bulge that also contains the inner high-alpha disk stars. M31 experienced a similar major satellite merger 3 Gyr ago which greatly heated and mixed the pre-existing high-metallicity disk, and also caused a massive inflow of gas and the formation of a dynamically hot secondary inner disk. Such a merger is consistent with the wide-spread star formation event 2-4 Gyr ago seen in disk colour-magnitude diagrams, and with the major substructures and metal-rich stars in the inner halo of M31 , when comparing photometric and recent spectroscopic data with available models. The merged satellite must have had a broad metallicity distribution and would have been the third most massive galaxy in the Local Group before the merger.
- Speaker: Ortwin Gerhard, MPE (Garching)
- Thursday 15 May 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: .
Was a famous supernova an alien invader from another galaxy?
Wed 14 May 13:15: Noise from Above: Determining the Impact of Starlink's Unintended Electromagnetic Radiation on REACH
21-cm cosmology experiments have opened new frontiers in our quest to explore the early universe. However, the rapid expansion of satellite constellations in Low Earth Orbit (LEO) poses a significant threat. SpaceX’s Starlink is particularly concerning due to unintended electromagnetic radiation (UEMR) generated by its hardware and onboard electronic subsystems, as reported by observatories such as the Low-Frequency Array (LOFAR). These emissions could contaminate observations of the faint 21-cm signal, already buried beneath foreground emissions and radio frequency interference (RFI). The Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) is a low-frequency radio telescope based in the Karoo radio reserve, South Africa, designed to detect the global 21-cm signal from Cosmic Dawn. In this talk, I will present my ongoing work assessing the extent to which Starlink impacts REACH . My approach combines orbital trajectory simulations using Two-Line Element (TLE) catalogues with geometric constraints to identify Starlink flyovers within REACH ’s field of view. These are cross-referenced with power spectral density (PSD) measurements to search for correlations indicating UEMR , including Doppler shift analysis. I conclude by outlining plans to automate this process and how this work contributes to broader efforts to safeguard radio astronomy from satellite interference.
- Speaker: Gabriella Rajpoot / Cavendish Laboratory
- Wednesday 14 May 2025, 13:15-13:40
- Venue: The Hoyle Lecture Theatre + Zoom .
- Series: Institute of Astronomy Seminars; organiser: .
Wed 14 May 13:15: Noise from Above: Determining the Impact of Starlink's Unintended Electromagnetic Radiation on REACH
21-cm cosmology experiments have opened new frontiers in our quest to explore the early universe. However, the rapid expansion of satellite constellations in Low Earth Orbit (LEO) poses a significant threat. SpaceX’s Starlink is particularly concerning due to unintended electromagnetic radiation (UEMR) generated by its hardware and onboard electronic subsystems, as reported by observatories such as the Low-Frequency Array (LOFAR). These emissions could contaminate observations of the faint 21-cm signal, already buried beneath foreground emissions and radio frequency interference (RFI). The Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) is a low-frequency radio telescope based in the Karoo radio reserve, South Africa, designed to detect the global 21-cm signal from Cosmic Dawn. In this talk, I will present my ongoing work assessing the extent to which Starlink impacts REACH . My approach combines orbital trajectory simulations using Two-Line Element (TLE) catalogues with geometric constraints to identify Starlink flyovers within REACH ’s field of view. These are cross-referenced with power spectral density (PSD) measurements to search for correlations indicating UEMR , including Doppler shift analysis. I conclude by outlining plans to automate this process and how this work contributes to broader efforts to safeguard radio astronomy from satellite interference.
- Speaker: Gabriella Rajpoot / Cavendish Laboratory
- Wednesday 14 May 2025, 13:15-13:40
- Venue: The Hoyle Lecture Theatre + Zoom .
- Series: Institute of Astronomy Seminars; organiser: .
Thu 22 May 16:00: The effect of binary mass transfer on the late evolution, death, and afterlife of massive stars
Gravitational-wave observations have revealed the population of stellar remnants from a new angle. Yet their stellar progenitors remain uncertain, in particular in the case of black holes. At least a fraction of these stars is believed to form in isolated binary systems. In this talk, I will discuss how binary mass transfer affects the late evolution and final fate of massive stars. The focus will be on stars that transfer their outer layers to a companion star and become binary-stripped. Binary-stripped stars develop systematically different core structures compared to single stars. I will discuss consequences for supernovae, black hole formation, and gravitational-wave observations.
- Speaker: Eva laplace, University of Leuven, Belgium
- Thursday 22 May 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: ag2017.
Thu 22 May 16:00: The effect of binary mass transfer on the late evolution, death, and afterlife of massive stars
Gravitational-wave observations have revealed the population of stellar remnants from a new angle. Yet their stellar progenitors remain uncertain, in particular in the case of black holes. At least a fraction of these stars is believed to form in isolated binary systems. In this talk, I will discuss how binary mass transfer affects the late evolution and final fate of massive stars. The focus will be on stars that transfer their outer layers to a companion star and become binary-stripped. Binary-stripped stars develop systematically different core structures compared to single stars. I will discuss consequences for supernovae, black hole formation, and gravitational-wave observations.
- Speaker: Eva laplace, University of Leuven, Belgium
- Thursday 22 May 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: ag2017.