In this months episode Exocasters Hugh Osborn, Hannah Wakeford, and Andrew Rushby attempt to answer the question they posed last year: What is the point of the Habitable Zone?

The term Habitable Zone is often thrown around by scientists, the media, and in the general public. But what does the term really mean and how do we use it. Join us in what is at points a heated discussion on all the aspects of the science and language involved in this hot cool just right topic.

The #ExoCup2020 was full of wonderful and baffling surprises. The Exocast team take a look at what went on, which planets triumphed or failed, and what you did to bring this competition to life.

This year’s competition was a true reflection of 2020. We had election fatigue bloom into campaign videos. Exoplanets making their own twitter accounts to ask for your vote. YouTubers, live streamers, and parody accounts asking you to vote for a specific planet. But most importantly we had some amazing exoplanet science shared with everyone.

If you enjoy our content and want to support the Exocast team then pop over to our Buy Me a Coffee page. For just $10 you can also put your favorite exoplanet in for a potential wildcard slot in #ExoCup2021!

In this special episode after a long summer break, the Exocast team performs the draw for the upcoming Exocup – the foremost exoplanetary competition in which 32 twitter polls will comprehensively and uncontroversially* decide on the world’s favourite exoplanet.
* This may be wishful thinking

This month Hugh, Andrew, and Hannah talk to astrophysicist, folklorist, and science communicator Moiya McTier. Moiya is an NSF graduate researcher at Columbia University in New York City and works to understand exoplanets from a galactic perspective.

The Exocast team talks to Moiya about work from measuring the topography on an exoplanet by the effect that mountains and other features have in transit, all the way up to how the stars in the Milky Way are moving and the effects those might have on their planets. The blended approach Moiya takes to science with a look too folklore and the way we perceive our universe gives a new spin to the way we can view and measure exoplanets and our universe. We chat about how to best communicate what astronomy is to others and how to make the right connections.

We also take the opportunity to talk to Moiya about what it is like to be a black woman in the astronomy community. The value of familiarity and shared experience in any field is important and we need to be more aware of ourselves and others to make this field more inclusive. See, think, act.

Concrete Steps for Recruiting, Supporting, and Advancing Underrepresented Minoritized Scientists

UK Actions and resources for #BlackLivesMatter

• Buzzword alert! A mini-Neptune and Venus-zone planet in the radius valley orbiting an M2 star has been validated with the Habitable-zone planet finder.
• Four jovian sized worlds discovered around the low luminosity stars
• Wendelstein-1b and 2b
• A habitable-zone planet in Kepler-160?
• The finally published discovery of AU Mic b
• Discovery of Gliese 887b & c

• Ultra-hot Jupiter WASP-121b got two papers this month. One looking for Cr and V, and the other cataloging an array of metals in its atmosphere.
• Hubble WFC3 IR grism spectroscopy of the warm Neptune HD 106315c
• Another search for TiO in the atmosphere of WASP-33b.
• Hubble PanCET program has a new transmission spectrum out of HAT-P-32b
• TESS phasecurve observations of the brown dwarf KELT-1b
• The most likely clouds muting and obscuring molecular features in transmission spectra are composed of magnesium silicates.
•  3D GCM models to map the formation of hydrocarbon haze in the atmosphere of WASP-43b

• Mineral dust increases the habitability of terrestrial planets but confounds biomarker detection
• The Effect Of Varying Atmospheric Pressure Upon Habitability And Biosignatures Of Earth-like Planets
• Reports from the Goldschmidt conference
• and… The strangely precise conclusion that there are 36 intelligent civilisations in out galaxy.

In this episode, the team sits down to ponder the question how many exoplanets are there?

At first, this might seem like a relatively straightforward question that can be answered by NASA’s Exoplanet Archive, but it becomes more daunting when considering, for example, the biases and limitations of our instruments that affect our ability to even detect and characterise many planets, how we define a ‘planet’, and whether or not we have surveyed enough stars to consider our sample of planet-hosting stars to be representative of the wider stellar population.

But, at the core of this topic, are some of the fundamental questions and motivations that have always made us, as humans, look up at the night-sky and wonder if any of those stars had, in their orbit, a planet like our own.

So, listen along as the team makes an attempt at tackling this tricky question with a bit of statistics, a bit of astronomy, a little philosophy, and even a well-developed fishing metaphor (a first for the show).

This month Andrew, Hannah, and Hugh chat with Dr Batiste Journaux (Research Associate in the Department of Earth and Space Science at the University of Washington) about all things icy and the role of different ices in our Solar System and exoplanets. Baptiste is a multidisciplinary scientist whose research spans the lab, fieldwork, and modelling and software development, we talk about how these all fit together to explore alien worlds in our solar system and beyond.

In this episode we learn how you form “hot ice”, the best way to measure ices in the interior of other worlds, and how the properties of different ices can shape another world.

Adopted Planet: TRAPPIST-1g – possible one of the best “ocean worlds” with high pressure ices. Future observations of this world might help us understand more about icy exoplanets. It joins its sibling TRAPPIST-1h in our adopted exoplanet family.

ExoCup2019 Français: Baptiste also translated our ExoCup2019 cards into French. So, for all our French speaking listeners you can find the translated cards here.

On Exocast-45d we bring you the news from across exoplanet research this month with new discoveries, characterisations, habitability and formation papers.

• In America, WFIRST has been renamed the Nancy Grace Roman Space Telescope in honour to the pioneering “Mother Hubble”, while in Europe the LIFE mission kicked off.
• We have lots of new exoplanets being discovered (from TESS, NGTS, WASP and RVs), and un-discovered, as was the case for Fomalhaut b.
• Characterisation studies have also been busy this month with three papers released looking at data on the hot Jupiter WASP-76b, an unusual transmission spectrum for KELT-11b, and the He atmosphere of GJ3470b gets another look from more data.
• Formation has also been a hot topic and we look at a new paper from pioneers in the field looking to explain the formation of moons around giant planets like Jupiter.
• And in habitability we delve into a new Bayesian approach to the problem of timelines and probability for the Earth, plus a look at Venus’ habitable past.

On this episode we ask the question: Can we ever image the surface of an exoplanet?

Once we get all the definitions out of the way, like ‘what do we mean by map?’ and ‘what do we mean by surface?’, we take a deep dive into the realm of instrumentation to discuss the possibilities and limitations of our upcoming and near-future exoplanet imaging technologies.

We touch on some of the avenues that astronomers & engineers already thought about to do this, consider if it’s technologically feasible that we might be able to return images of the surface of another world, and try and understand the drivers behind why we want to do this in the first place.

In this round-up of the month’s notable exoplanetary exploits, we cover all the headlines including: Proxima c (not) being directly imaged with Sphere – WASP-4b’s accelerating orbit – two new but very different sub-Saturn-mass planets – windspeed measurements on Brown Dwarfs – plus the influence of Gin & Vampires on exoplanets (from a couple of results very early this month).

Also this month, check out our chat with Dr Sarah Casewell; and a discussion of imaging the surfaces of exoplanets.