Heavy Metals, Global Winds and Evaporating Worlds: High-Resolution Spectroscopy of Ultra-Hot Jupiters
Borsato, Nicholas William LU
(2026)
- Abstract
- One of the biggest questions people ask astronomers is whether life exists elsewhere in the universe. Unfortunately, we don’t yet have an answer. Instead, progress towards an answer comes in small, careful steps. This thesis is one of those steps.
My research has focused on the atmospheres of "ultra-hot Jupiters": planets the size of Jupiter that orbit so close to their stars they are heated to thousands of degrees. At those extremes, their atmospheres behave almost like water in a boiling pot, except it isn’t just water that evaporates, it's the atmosphere.
These worlds may sound exotic, but paradoxically they are the easiest planets for us to observe. When they pass in front of their stars, starlight filters through... (More) - One of the biggest questions people ask astronomers is whether life exists elsewhere in the universe. Unfortunately, we don’t yet have an answer. Instead, progress towards an answer comes in small, careful steps. This thesis is one of those steps.
My research has focused on the atmospheres of "ultra-hot Jupiters": planets the size of Jupiter that orbit so close to their stars they are heated to thousands of degrees. At those extremes, their atmospheres behave almost like water in a boiling pot, except it isn’t just water that evaporates, it's the atmosphere.
These worlds may sound exotic, but paradoxically they are the easiest planets for us to observe. When they pass in front of their stars, starlight filters through their atmospheres and into our telescopes. By applying a technique called cross-correlation, I can detect the \say{fingerprints} of gases and even trace winds racing around them at thousands of kilometres per hour.
A key part of my work has been to make this technique more reliable, ensuring that the signals we claim are genuine and not just noise. In doing so, I’ve shown that even smaller telescopes, ones often overlooked for this kind of work, can still reveal remarkable detail. That matters, because it means more observatories around the world can join in, and more data can be brought to bear the study of exoplanet atmospheres.
Ultra-hot Jupiters orbit their stars on timescales of just a few Earth days, making their transits predictable and easy to observe with high precision since they occur frequently. Each observation builds on the last, steadily improving our ability to interpret atmospheric signals. By studying these extreme worlds, we refine the tools needed to probe smaller, cooler planets, ultimately bringing us closer to the long-term goal of identifying an "Earth-twin".
(Less) - Abstract (Swedish)
- En av de vanligaste frågorna som brukar ställas till astronomer är om det finns liv någon annanstans i universum. Vi har ännu inget enkelt svar. Framsteg mot ett svar på denna fråga görs lite i taget. Den här avhandlingen är ett av dessa steg.
Min forskning är inriktad på atmosfärerna hos så kallade "ultra-hot Jupiters": planeter i Jupiters storlek som kretsar så nära sina stjärnor att de hettas upp till flera tusen grader. Under dessa extrema förhållanden beter sig atmosfärerna nästan som vatten i en kokande kastrull, men det är inte bara vatten som avdunstar, utan även metaller och andra tunga gaser.
Dessa världar kan låta exotiska, men paradoxalt nog är de bland de enklaste planeterna att studera. När de passerar... (More) - En av de vanligaste frågorna som brukar ställas till astronomer är om det finns liv någon annanstans i universum. Vi har ännu inget enkelt svar. Framsteg mot ett svar på denna fråga görs lite i taget. Den här avhandlingen är ett av dessa steg.
Min forskning är inriktad på atmosfärerna hos så kallade "ultra-hot Jupiters": planeter i Jupiters storlek som kretsar så nära sina stjärnor att de hettas upp till flera tusen grader. Under dessa extrema förhållanden beter sig atmosfärerna nästan som vatten i en kokande kastrull, men det är inte bara vatten som avdunstar, utan även metaller och andra tunga gaser.
Dessa världar kan låta exotiska, men paradoxalt nog är de bland de enklaste planeterna att studera. När de passerar framför sina stjärnor filtreras stjärnljuset genom deras atmosfärer och in i våra teleskop. Med hjälp av en teknik som kallas korskorrelation kan jag upptäcka gasernas "fingeravtryck'" och till och med följa vindar som blåser runt planeterna i hastigheter på tusentals kilometer i timmen.
En central del av mitt arbete har varit att göra denna metod mer tillförlitlig, så att de signaler vi tolkar verkligen är äkta och inte bara brus. Jag har också visat att även mindre teleskop, som ofta förbises för den här typen av forskning, kan avslöja anmärkningsvärda detaljer. Det innebär att fler observatorier runt om i världen kan bidra, och att mer data kan samlas in för att besvara de stora frågorna.
Ultra-hot Jupiters kretsar runt sina stjärnor på bara några dagar, vilket leder till att deras omlopp både är förutsägbara och enkla att observera med hög precision. Varje observation bygger vidare på den föregående och förbättrar gradvis vår förmåga att tolka atmosfäriska signaler. Genom att studera dessa extrema världar förfinar vi de verktyg som behövs för att undersöka mindre och svalare planeter, och tar därmed steg närmare målet att en dag kunna identifiera en "Earth twin". (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/279bd900-94e6-4314-a866-4ea870a22457
- author
- Borsato, Nicholas William
LU
- supervisor
- opponent
-
- Prof. Dr Palle, Enric, Institute of Astrophysics of the Canary Islands (IAC)
- organization
- alternative title
- Tunga metaller, globala vindar och avdunstande världar: högupplöst spektroskopi av ultrahot Jupiters
- publishing date
- 2026-02-10
- type
- Thesis
- publication status
- published
- subject
- keywords
- Planets and satellites: atmospheres, Planets and satellites: gaseous planets, Techniques: spectroscopic, Techniques: radial velocities, methods: Data analysis
- pages
- 177 pages
- publisher
- Lund University
- defense location
- Rydbergsalen, Department of Physics. Join via zoom: https://lu-se.zoom.us/j/64273302209
- defense date
- 2026-03-27 09:00:00
- ISBN
- 978-91-8104-798-1
- 978-91-8104-799-8
- language
- English
- LU publication?
- yes
- id
- 279bd900-94e6-4314-a866-4ea870a22457
- date added to LUP
- 2026-02-10 07:39:43
- date last changed
- 2026-03-06 08:34:18
@phdthesis{279bd900-94e6-4314-a866-4ea870a22457,
abstract = {{One of the biggest questions people ask astronomers is whether life exists elsewhere in the universe. Unfortunately, we don’t yet have an answer. Instead, progress towards an answer comes in small, careful steps. This thesis is one of those steps.<br/><br/>My research has focused on the atmospheres of "ultra-hot Jupiters": planets the size of Jupiter that orbit so close to their stars they are heated to thousands of degrees. At those extremes, their atmospheres behave almost like water in a boiling pot, except it isn’t just water that evaporates, it's the atmosphere.<br/><br/>These worlds may sound exotic, but paradoxically they are the easiest planets for us to observe. When they pass in front of their stars, starlight filters through their atmospheres and into our telescopes. By applying a technique called cross-correlation, I can detect the \say{fingerprints} of gases and even trace winds racing around them at thousands of kilometres per hour.<br/><br/>A key part of my work has been to make this technique more reliable, ensuring that the signals we claim are genuine and not just noise. In doing so, I’ve shown that even smaller telescopes, ones often overlooked for this kind of work, can still reveal remarkable detail. That matters, because it means more observatories around the world can join in, and more data can be brought to bear the study of exoplanet atmospheres.<br/><br/>Ultra-hot Jupiters orbit their stars on timescales of just a few Earth days, making their transits predictable and easy to observe with high precision since they occur frequently. Each observation builds on the last, steadily improving our ability to interpret atmospheric signals. By studying these extreme worlds, we refine the tools needed to probe smaller, cooler planets, ultimately bringing us closer to the long-term goal of identifying an "Earth-twin".<br/><br/>}},
author = {{Borsato, Nicholas William}},
isbn = {{978-91-8104-798-1}},
keywords = {{Planets and satellites: atmospheres; Planets and satellites: gaseous planets; Techniques: spectroscopic; Techniques: radial velocities; methods: Data analysis}},
language = {{eng}},
month = {{02}},
publisher = {{Lund University}},
school = {{Lund University}},
title = {{Heavy Metals, Global Winds and Evaporating Worlds: High-Resolution Spectroscopy of Ultra-Hot Jupiters}},
url = {{https://lup.lub.lu.se/search/files/242420966/Thesis_Nicholas_Borsato_LUCRIS_fixed.pdf}},
year = {{2026}},
}