Sarah Casewell

Favourite Thing: Go observing! I also love reducing data, which sounds odd. But there is a magical feeling knowing that you are the first person to see what that star is made of. That’s a pretty fantastic feeling!



Heathfield High School, 1992-2000, University of Leicester 2000-2007


GCSEs 11 A*-C, A levels: Physics, Maths, Chemistry, General studies, AAAA, As level, German B

Work History:

MPhys Physics with Space Science and Technology, 1st class. PhD in Astronomy

Current Job:

Postdoctoral Researcher


University of Leicester

Me and my work

I research brown and white dwarfs – failed and dead stars!

My name is Sarah and I am an observational astronomer. This means I use telescopes, both on the ground and in space to study astronomical objects – in my case stars. I research two types of dwarf star – brown dwarfs and white dwarfs.

Brown dwarfs are failed stars – they form like stars, but never burn hydrogen into helium. This means they end up about the size of Jupiter, with masses between 70 and 13 jupiter masses. They start off quite hot, 3000 degrees or so, but then cool over time. This means they get cool enough to have molecules, like water and methane in their atmospheres. They have weather, and clouds and even lightning. I study these objects when they are in binaries with other stars, and are being heated by their hotter companion.

White dwarfs are dead stars – our Sun will become on in 5 billion years time. They are vey dense, with about the mass of the sun squeezed into a sphere the size of the Earth. Because they are so dense, they have unusual properties and are very hot – hotter than the sun.

I study the relationship between their current mass, and their mass when they were a star, as well as the relationship between their mass and radius.



My Typical Day

Reducing or analysing data on my laptop.

I have 2 sorts of day.

My favourite day is when I’m observing and have to fly to Chile, Hawaii or the canary islands to use telescopes. There I get up at lunchtime and  have a look at the previous night’s data – see if I need to observe anything again, check if the instrument was working ok, etc. I then check the weather report for the coming night.  Then I have to have dinner at about 5pm, pick up my packed lunch and drive up the mountain to the telescope.   At the telescope, I then make sure everything is turned on, open the dome and sides to get the airflow in, and start to do the evening calibrations. Once the sun has set we can start the twilight calibrations, and then when it’s dark begin observing! I normally finish between 7 and 9am depending on the season.

My more normal day involves checking email, reducing data and analysing it. Writing reports of my work and writing proposals for more telescope time. Sometimes I also have to give lectures to the undergraduates or meet students who need help reducing data or with their analysis.


What I'd do with the money

Start a scheme for local schools to come and have a night at our University observatory

I currently have a royal society partnership grant with a local school and as part of this, 60 year 10 and year 11 students will be camping out at our University observatory at the University of Leicester and using the telescopes all night (this may also involve barbecues and/or pizza!). It’s a fantastic opportunity to learn about the night sky, and the hope is they will catch the astronomy bug and start their own astronomy club at school.

If I won, I would extend this to other local high schools offering the opportunity to more students in Leicester.

My Interview

How would you describe yourself in 3 words?

Enthusiastic, lively, quirky?

Who is your favourite singer or band?


What's your favourite food?


What is the most fun thing you've done?

Trekking across night to see lava erupting from a volcano on Hawaii

What did you want to be after you left school?

Working for NASA

Were you ever in trouble in at school?


What was your favourite subject at school?


What's the best thing you've done as a scientist?

Learning to run an 8m telescope and travelling the world!

What or who inspired you to become a scientist?

My science teacher Dr Griffiths and watching Apollo 13

If you weren't a scientist, what would you be?

I have no idea – communicating science in some way

If you had 3 wishes for yourself what would they be? - be honest!

To have cats, vist antarctica (the only continent I’ve not visited), to see the northern lights

Tell us a joke.

Really? Ok, although it’s slightly nerdy. There are 10 types of people in the world…those that understand binary, and those that don’t!

Other stuff

Work photos:

myimage2 My workstation at a telescope! I have 4 screens on the left which are images of the data from each of the 4 cameras, and the 2 on the right show me the weather and where the telescope is pointing, how long I have left on my exposure etc.

myimage3 This is me with the telescope I was using. It’s called UKIRT or the United Kingdom InfraRed Telescope and is on Mauna Kea on Hawaii. I’m stood under the telescope next to my instrument which is called UFTI. It’s at Cassegrain focus, which means it’s at the back of the telescope, behind the mirror.

myimage4 I do a lot of outreach, including knitting a brown dwarf (see it in action here! ) who comes with me on school visits – follow @knitted_bd on twitter!

myimage5 I also work towards promoting women in science and engineering with ScienceGrrl and other organisations. I got to go to the Royal Society in Edinburgh to collect our department’s Athena Swan award for women in science.