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A Pathway to the Confirmation and Characterisation of Habitable Alien Worlds

Since the confirmation of the first planets outside our solar system in the 1990s, we have made tremendous progress towards answering this question. Yet, the confirmation of a true Earth-analogue still evades us. On top of this, if we are truly to understand the origins of life in the cosmos, we must also create a complete picture of planetary formation, evolution, and habitability.

However, each of these aspects necessitates a detailed knowledge of solar-type stars. This is because we study exoplanets indirectly by analysing their much more luminous host stars. For example, most planet confirmation relies on the Doppler wobble of the host star, induced by the planet. Moreover, we can learn about a planet's dynamical history from mapping its projected orbit as it transits its host star. Hence, stellar surface inhomogeneities can impact planetary interpretations, and can completely swamp the signals from rocky worlds.

My research, as a UKRI Future Leaders Fellow, aims to overcome these hurdles. For this, I study stellar surfaces from a two-pronged approach: with state-of-the-art 3D simulations and using transiting planets to empirically probe stellar surfaces.

Abstract:
Are we alone in the Universe? Since the confirmation of the first planets outside our solar system in the 1990s, we have made tremendous progress towards answering this question. Yet, the confirmation of a true Earth-analogue still evades us. On top of this, if we are truly to understand the origins of life in the cosmos, we must also create a complete picture of planetary formation, evolution, and habitability. However, each of these aspects necessitates a detailed knowledge of Sun-like stars. This is because we study exoplanets indirectly by analysing their much more luminous host stars. For example, most planet confirmation relies on the Doppler wobble of the host star, induced by the presence of the planet. Moreover, we can learn about a planet's dynamical history from mapping its projected orbit as it transits its host star. Hence, if there are inhomogeneities on the stellar surface, they can impact planetary interpretations and even completely swamp the signals from rocky worlds. In this talk, I will discuss how we confirm and characterise planets outside our solar system and how our knowledge of their host stars poses a fundamental hurdle we must overcome on the pathway to rocky, temperate worlds.


Phosphine detected in Venus' atmosphere

On 14 September 2020, a team of astronomers led by Dr Jane Greaves of Cardiff University announced the detection of phosphine, a potential biomarker, in the atmosphere of Venus. On Earth, phosphine can result from natural processes such as lightning and volcanic activity, but only in small amounts; by comparison, the amount of phosphine detected in Venus' atmosphere is relatively large. The only known processes that produce phosphine on Earth in similar quantities are biological in origin.

It must be stressed that this does not mean that there is life on Venus. What has been announced is a signal that is a possible sign of life, with a strength for which there are no plausible known abiotic explanations. There may, of course, be currently unknown methods of producing it in the amounts required. But this is still an exciting signal that warrants more investigation.

Thu 08 Oct 2020, 12:00 | Tags: news, Astrobiology, astronomy, Venus, phosphine, biomarkers

Exploring the stars: Six star types you should know about

We are familiar with the idea that the twinkling pinpricks of light in the sky are stars, like our own Sun, but not all those stars are the same. There are many types of stars, and we can see most of these in the night sky, explains Dr Elizabeth Stanway.

Fri 19 Jun 2020, 10:00 | Tags: outreach, CEH, KnowledgeCentre, astronomy, article

Astronomy at a distance: Sundials

Professor Tom Marsh from the Astronomy and Astrophysics Group explains how to make a sundial and what it can tell us about our Sun.

Fri 12 Jun 2020, 10:00 | Tags: outreach, CEH, KnowledgeCentre, astronomy, article

Observing the planets

It’s quite easy to see some of the other planets in our Solar system from your garden, balcony or on an evening walk. In fact, you might have already seen them without realising it, explains Dr David Brown from Warwick’s astrophysics team.

Fri 05 Jun 2020, 10:00 | Tags: outreach, CEH, KnowledgeCentre, astronomy, article

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