Linn Boldt-Christmas
@nplinnspace.bsky.social
🇸🇪 Exoplanet atmospheres + chemistry + formation at Uppsala University 🪐🔭 Also into astrobiology, policy, climate, equality/EDI, and scicomm ✨ (she/her) – linnboldtchristmas.wordpress.com
Pinned
VLT/CRIRES+ observations of warm Neptune WASP-107 b: Molecular detections and challenges in ground-based transmission spectroscopy of cooler and cloudy exoplanets
Atmospheres of transiting exoplanets can be studied spectroscopically using space-based or ground-based observations. Each has its own strengths and weaknesses, so there are benefits to both approache...
arxiv.org
Do you love WASP-107 b? Do you love making use of *both* ground VLT + space JWST obs to detect molecules in a "warm" (Teq<800K) #exoplanet in transmission, even in a crazy confusing cloudy atmosphere?!
🚨 It's PAPER* DAY! Which means #scicomm thread!
🧵⬇️🔭🪐🧪
*pre-print!
arxiv.org/abs/2508.18964
🚨 It's PAPER* DAY! Which means #scicomm thread!
🧵⬇️🔭🪐🧪
*pre-print!
arxiv.org/abs/2508.18964
Reposted by Linn Boldt-Christmas
Happy solstice! 🌍❄️ Today (Dec 21) at 16:03 (CET or UTC+1) winter officially begins. Shortest day of the year, but your noon shadow will be the longest. From now on, days slowly start getting longer again. Animation by NAAP labs (University of Nebraska-Lincoln) 🧪⚛️🔭#astronomy
December 21, 2025 at 8:53 AM
Happy solstice! 🌍❄️ Today (Dec 21) at 16:03 (CET or UTC+1) winter officially begins. Shortest day of the year, but your noon shadow will be the longest. From now on, days slowly start getting longer again. Animation by NAAP labs (University of Nebraska-Lincoln) 🧪⚛️🔭#astronomy
Reposted by Linn Boldt-Christmas
Terrifying headline if you don’t realize they are sports teams.
December 19, 2025 at 4:37 PM
Terrifying headline if you don’t realize they are sports teams.
Reposted by Linn Boldt-Christmas
Oh to be a little Tardigrade walking across a microscopic slide. 🫧🐻🧪
December 16, 2025 at 7:00 PM
Oh to be a little Tardigrade walking across a microscopic slide. 🫧🐻🧪
Reposted by Linn Boldt-Christmas
Did all life start with RNA? Some scientists think so – and a new experiment suggests it might have formed naturally on many worlds.
Story by me in Scientific American
www.scientificamerican.com/article/rna-...
Story by me in Scientific American
www.scientificamerican.com/article/rna-...
Rocky Planets May Make Life’s Precursor, RNA, All across the Universe
New experiments show how RNA might form not just on Earth but on other rocky planets, too
www.scientificamerican.com
December 16, 2025 at 7:55 AM
Did all life start with RNA? Some scientists think so – and a new experiment suggests it might have formed naturally on many worlds.
Story by me in Scientific American
www.scientificamerican.com/article/rna-...
Story by me in Scientific American
www.scientificamerican.com/article/rna-...
So fun to see our work on #exoplanet WASP-127 b, led by the incredible Lisa Nortmann, as one of the "Top 10 Breakthroughs" of 2025 according to @physicsworld.bsky.social! 🔭🧪
Check it out below ⬇️ including a BUNCH more cool things I had no idea happened this year?!
physicsworld.com/a/top-10-bre...
Check it out below ⬇️ including a BUNCH more cool things I had no idea happened this year?!
physicsworld.com/a/top-10-bre...
December 12, 2025 at 4:32 PM
So fun to see our work on #exoplanet WASP-127 b, led by the incredible Lisa Nortmann, as one of the "Top 10 Breakthroughs" of 2025 according to @physicsworld.bsky.social! 🔭🧪
Check it out below ⬇️ including a BUNCH more cool things I had no idea happened this year?!
physicsworld.com/a/top-10-bre...
Check it out below ⬇️ including a BUNCH more cool things I had no idea happened this year?!
physicsworld.com/a/top-10-bre...
Reposted by Linn Boldt-Christmas
AbSciCon2026
Madison, WI USA, 17-22 May, 2026
On behalf of myself and my co-convenors, I am pleased to announce the session:
43 - Habitable subNeptunes: Theory and prospects for observational identification
Details and submission at:
agu.confex.com/agu/abscicon...
Madison, WI USA, 17-22 May, 2026
On behalf of myself and my co-convenors, I am pleased to announce the session:
43 - Habitable subNeptunes: Theory and prospects for observational identification
Details and submission at:
agu.confex.com/agu/abscicon...
Habitable subNeptunes: Theory and prospects for observational identification
subNeptunes have emerged as a fruitful target for atmospheric characterization, with several robust identifications of atmospheric constituents and mean molecular weight already in hand. Linked topic...
agu.confex.com
December 10, 2025 at 11:56 AM
AbSciCon2026
Madison, WI USA, 17-22 May, 2026
On behalf of myself and my co-convenors, I am pleased to announce the session:
43 - Habitable subNeptunes: Theory and prospects for observational identification
Details and submission at:
agu.confex.com/agu/abscicon...
Madison, WI USA, 17-22 May, 2026
On behalf of myself and my co-convenors, I am pleased to announce the session:
43 - Habitable subNeptunes: Theory and prospects for observational identification
Details and submission at:
agu.confex.com/agu/abscicon...
Reposted by Linn Boldt-Christmas
Mind-blowing new paper just out! 🧪
A research team used #Gaia to create the most detailed 3D census to date of OB associations within ~1000 ly from the Sun.
Result? 🔭
57 groups of massive stars — twice as many as we knew before — that were born together and are now slowly drifting apart.
1/4
A research team used #Gaia to create the most detailed 3D census to date of OB associations within ~1000 ly from the Sun.
Result? 🔭
57 groups of massive stars — twice as many as we knew before — that were born together and are now slowly drifting apart.
1/4
A new census of OB associations with Gaia!
In this study, we took advantage of my OB stars map to find new OB associations within 1 kpc. The goal was to create a useful reference catalogue for this era, and to trace the star formation and structure of the local Milky Way.
#stellarastro #galactic
In this study, we took advantage of my OB stars map to find new OB associations within 1 kpc. The goal was to create a useful reference catalogue for this era, and to trace the star formation and structure of the local Milky Way.
#stellarastro #galactic
December 9, 2025 at 9:47 AM
Mind-blowing new paper just out! 🧪
A research team used #Gaia to create the most detailed 3D census to date of OB associations within ~1000 ly from the Sun.
Result? 🔭
57 groups of massive stars — twice as many as we knew before — that were born together and are now slowly drifting apart.
1/4
A research team used #Gaia to create the most detailed 3D census to date of OB associations within ~1000 ly from the Sun.
Result? 🔭
57 groups of massive stars — twice as many as we knew before — that were born together and are now slowly drifting apart.
1/4
Reposted by Linn Boldt-Christmas
TIL about a memorial ceremony in Iceland in 2019 to mark the end of a glacier, changing the place name from Okjökull to Ok (jökull = glacier). Uncompromising wording on the bronze plaque:
"This is to acknowledge that we know what is happening and what needs to be done. Only you know if we did it".
"This is to acknowledge that we know what is happening and what needs to be done. Only you know if we did it".
December 7, 2025 at 5:17 PM
TIL about a memorial ceremony in Iceland in 2019 to mark the end of a glacier, changing the place name from Okjökull to Ok (jökull = glacier). Uncompromising wording on the bronze plaque:
"This is to acknowledge that we know what is happening and what needs to be done. Only you know if we did it".
"This is to acknowledge that we know what is happening and what needs to be done. Only you know if we did it".
Reposted by Linn Boldt-Christmas
Reposted by Linn Boldt-Christmas
Hi all! If you are looking for a conference in exoplanet interiors in 2026, check out "Layers of Understanding: Model Intercomparisons of Exoplanet Interiors": layersofunderstanding2026.github.io
It will take place in MPIA's campus in April 13-17th. The registration deadline is 15 January 2026
It will take place in MPIA's campus in April 13-17th. The registration deadline is 15 January 2026
December 5, 2025 at 9:37 AM
Hi all! If you are looking for a conference in exoplanet interiors in 2026, check out "Layers of Understanding: Model Intercomparisons of Exoplanet Interiors": layersofunderstanding2026.github.io
It will take place in MPIA's campus in April 13-17th. The registration deadline is 15 January 2026
It will take place in MPIA's campus in April 13-17th. The registration deadline is 15 January 2026
Reposted by Linn Boldt-Christmas
The interstellar visitor 3I/ATLAS ☄️ cruising through our Solar System is no alien spaceship and won't hit Earth.
Still, the buzz around it is far from unfounded 🤩
Discover why with #ChasingStarlight: https://www.youtube.com/watch?v=YtiqLxfSiVI
🔭 🧪
Still, the buzz around it is far from unfounded 🤩
Discover why with #ChasingStarlight: https://www.youtube.com/watch?v=YtiqLxfSiVI
🔭 🧪
December 5, 2025 at 10:03 AM
The interstellar visitor 3I/ATLAS ☄️ cruising through our Solar System is no alien spaceship and won't hit Earth.
Still, the buzz around it is far from unfounded 🤩
Discover why with #ChasingStarlight: https://www.youtube.com/watch?v=YtiqLxfSiVI
🔭 🧪
Still, the buzz around it is far from unfounded 🤩
Discover why with #ChasingStarlight: https://www.youtube.com/watch?v=YtiqLxfSiVI
🔭 🧪
Reposted by Linn Boldt-Christmas
Published in #MNRAS: "Redefining interiors and envelopes: hydrogen–silicate miscibility and its consequences for the structure and evolution of sub-Neptunes", Rogers et al. This is Fig. 2: for the caption & to read the paper please visit academic.oup.com/mnras/articl...
December 5, 2025 at 10:06 AM
Published in #MNRAS: "Redefining interiors and envelopes: hydrogen–silicate miscibility and its consequences for the structure and evolution of sub-Neptunes", Rogers et al. This is Fig. 2: for the caption & to read the paper please visit academic.oup.com/mnras/articl...
Reposted by Linn Boldt-Christmas
A note on learning physics ⚛️ for starting PhD students:
At the risk of saying something completely useless because everyone has it worked out
There is no magic trick, your classmates *may* be faster than you, but they are still studying as long as they need to and you are quite capable of the same
At the risk of saying something completely useless because everyone has it worked out
There is no magic trick, your classmates *may* be faster than you, but they are still studying as long as they need to and you are quite capable of the same
December 4, 2025 at 9:18 PM
A note on learning physics ⚛️ for starting PhD students:
At the risk of saying something completely useless because everyone has it worked out
There is no magic trick, your classmates *may* be faster than you, but they are still studying as long as they need to and you are quite capable of the same
At the risk of saying something completely useless because everyone has it worked out
There is no magic trick, your classmates *may* be faster than you, but they are still studying as long as they need to and you are quite capable of the same
Reposted by Linn Boldt-Christmas
This is great news that Roman Space Telescope 🚀🔭 is functionally completed! Still some testing, and then Roman will move the Kennedy to be mated with the launch vehicle. Roman is a wide-field Hubble - exciting!
NASA has completed the construction of #NASARoman! Last month, technicians joined the inner and outer portions of the observatory in Maryland.
After final testing, Roman will move to the launch site at the Kennedy Space Center for launch preparations in summer 2026: https://go.nasa.gov/48EqnE8 🔭 🧪
After final testing, Roman will move to the launch site at the Kennedy Space Center for launch preparations in summer 2026: https://go.nasa.gov/48EqnE8 🔭 🧪
December 4, 2025 at 8:21 PM
This is great news that Roman Space Telescope 🚀🔭 is functionally completed! Still some testing, and then Roman will move the Kennedy to be mated with the launch vehicle. Roman is a wide-field Hubble - exciting!
Reposted by Linn Boldt-Christmas
Here's the aftermath of the Zhuque-3 landing impact.
December 4, 2025 at 6:36 AM
Here's the aftermath of the Zhuque-3 landing impact.
Reposted by Linn Boldt-Christmas
Reposted by Linn Boldt-Christmas
📢 Don't forget to join us for this talk tomorrow (Thursday)!
14:00 UTC = 15:00 CET = 09:00 EST = 06:00 PST = 23:00 JST
If you haven't signed up to our mailing list to access the Zoom-link, you can also watch it live on our YouTube channel 🔭☄️🧪 Livestream: www.youtube.com/watch?v=e2jI...
14:00 UTC = 15:00 CET = 09:00 EST = 06:00 PST = 23:00 JST
If you haven't signed up to our mailing list to access the Zoom-link, you can also watch it live on our YouTube channel 🔭☄️🧪 Livestream: www.youtube.com/watch?v=e2jI...
6,000 #exoplanets have been found to date, but ZERO of them are Earth-like planets around Sun-like stars! Why is that? Do any exist? Or is it just hard? ☀️🌍🔭
Join us on Thu 4 Dec @ 14:00 UTC for a #RockyWorldsDiscussion with Annelies Mortier to find out!
More: www.rockyworlds.org/event-detail... ☄️🧪
Join us on Thu 4 Dec @ 14:00 UTC for a #RockyWorldsDiscussion with Annelies Mortier to find out!
More: www.rockyworlds.org/event-detail... ☄️🧪
December 3, 2025 at 1:59 PM
📢 Don't forget to join us for this talk tomorrow (Thursday)!
14:00 UTC = 15:00 CET = 09:00 EST = 06:00 PST = 23:00 JST
If you haven't signed up to our mailing list to access the Zoom-link, you can also watch it live on our YouTube channel 🔭☄️🧪 Livestream: www.youtube.com/watch?v=e2jI...
14:00 UTC = 15:00 CET = 09:00 EST = 06:00 PST = 23:00 JST
If you haven't signed up to our mailing list to access the Zoom-link, you can also watch it live on our YouTube channel 🔭☄️🧪 Livestream: www.youtube.com/watch?v=e2jI...
Reposted by Linn Boldt-Christmas
Our #MarsExpress spots a strange shape on Mars, formed as a space rock collided with the planet's dusty surface.
It's known as a 'butterfly crater' but we see a walnut, an insect, the Eye of Sauron, or perhaps a moth... what do you think?
More info and images 👉 www.esa.int/Science_Expl...
🔭 🧪
It's known as a 'butterfly crater' but we see a walnut, an insect, the Eye of Sauron, or perhaps a moth... what do you think?
More info and images 👉 www.esa.int/Science_Expl...
🔭 🧪
December 3, 2025 at 10:38 AM
Our #MarsExpress spots a strange shape on Mars, formed as a space rock collided with the planet's dusty surface.
It's known as a 'butterfly crater' but we see a walnut, an insect, the Eye of Sauron, or perhaps a moth... what do you think?
More info and images 👉 www.esa.int/Science_Expl...
🔭 🧪
It's known as a 'butterfly crater' but we see a walnut, an insect, the Eye of Sauron, or perhaps a moth... what do you think?
More info and images 👉 www.esa.int/Science_Expl...
🔭 🧪
Reposted by Linn Boldt-Christmas
Interested in finding transiting planets at long periods, e.g. with the @platomissioncon.bsky.social?
We just published a Research Note led by Geert Jan Talens, showing that such transits can be much longer or shorter than usually assumed iopscience.iop.org/article/10.3...
We just published a Research Note led by Geert Jan Talens, showing that such transits can be much longer or shorter than usually assumed iopscience.iop.org/article/10.3...
December 3, 2025 at 12:21 PM
Interested in finding transiting planets at long periods, e.g. with the @platomissioncon.bsky.social?
We just published a Research Note led by Geert Jan Talens, showing that such transits can be much longer or shorter than usually assumed iopscience.iop.org/article/10.3...
We just published a Research Note led by Geert Jan Talens, showing that such transits can be much longer or shorter than usually assumed iopscience.iop.org/article/10.3...
Reposted by Linn Boldt-Christmas
I have eaten
the planets
that were in
the inner solar system
and which
you were probably
saving
for living on
Forgive me
they were delicious
so crunchy
and so warm
the planets
that were in
the inner solar system
and which
you were probably
saving
for living on
Forgive me
they were delicious
so crunchy
and so warm
Elderly stars just get hungry, and orbiting planets are *right there.* 🔭🧪
New research from Edward Bryant @uni-of-warwick.bsky.social and Vincent Van Eylen @University College London, input from Sabine Reffert @uniheidelberg.bsky.social, story by @bowlerhatscience.org. eos.org/articles/pla...
New research from Edward Bryant @uni-of-warwick.bsky.social and Vincent Van Eylen @University College London, input from Sabine Reffert @uniheidelberg.bsky.social, story by @bowlerhatscience.org. eos.org/articles/pla...
Planet-Eating Stars Hint at Earth’s Ultimate Fate - Eos
A sampling of aging Sun-like stars demonstrates that they likely eat their closest planets.
eos.org
December 2, 2025 at 4:42 PM
I have eaten
the planets
that were in
the inner solar system
and which
you were probably
saving
for living on
Forgive me
they were delicious
so crunchy
and so warm
the planets
that were in
the inner solar system
and which
you were probably
saving
for living on
Forgive me
they were delicious
so crunchy
and so warm
Reposted by Linn Boldt-Christmas
In ApJ today! Understanding the Origins of Super-puff Planets
iopscience.iop.org/article/10.3...
Main parts:
1) First sub-Neptune thermal evolution models to self-consistently couple to a hydrodynamic mass loss code.
2) The finding of a new XUV-driven mass-loss regime, "TEMP," for all sub-Neptunes
iopscience.iop.org/article/10.3...
Main parts:
1) First sub-Neptune thermal evolution models to self-consistently couple to a hydrodynamic mass loss code.
2) The finding of a new XUV-driven mass-loss regime, "TEMP," for all sub-Neptunes
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iopscience.iop.org
December 2, 2025 at 6:54 PM
In ApJ today! Understanding the Origins of Super-puff Planets
iopscience.iop.org/article/10.3...
Main parts:
1) First sub-Neptune thermal evolution models to self-consistently couple to a hydrodynamic mass loss code.
2) The finding of a new XUV-driven mass-loss regime, "TEMP," for all sub-Neptunes
iopscience.iop.org/article/10.3...
Main parts:
1) First sub-Neptune thermal evolution models to self-consistently couple to a hydrodynamic mass loss code.
2) The finding of a new XUV-driven mass-loss regime, "TEMP," for all sub-Neptunes
Reposted by Linn Boldt-Christmas
ALMA has captured extremely detailed radio images of the turbulent atmosphere of a dying star 📡 🌟
It observed tens of molecular spectral lines, each one revealing a different atmospheric layer.
Read more: www.almaobservatory.org/en/press-rel...
It observed tens of molecular spectral lines, each one revealing a different atmospheric layer.
Read more: www.almaobservatory.org/en/press-rel...
December 2, 2025 at 2:44 PM
ALMA has captured extremely detailed radio images of the turbulent atmosphere of a dying star 📡 🌟
It observed tens of molecular spectral lines, each one revealing a different atmospheric layer.
Read more: www.almaobservatory.org/en/press-rel...
It observed tens of molecular spectral lines, each one revealing a different atmospheric layer.
Read more: www.almaobservatory.org/en/press-rel...
Reposted by Linn Boldt-Christmas
🎉 🎉 🎉 UK & EUROPE COVER REVEAL 🎉 🎉 🎉
The Edge of Space-Time is coming to European readers via UK publisher @canongate.co.uk on 7 May 2026! With a slightly different subtitle 😂
Preorders now open! Please support your local indie. It helps authors so much!
buythebook.online/edge-of-spac... #BookSky
The Edge of Space-Time is coming to European readers via UK publisher @canongate.co.uk on 7 May 2026! With a slightly different subtitle 😂
Preorders now open! Please support your local indie. It helps authors so much!
buythebook.online/edge-of-spac... #BookSky
December 2, 2025 at 3:21 PM
🎉 🎉 🎉 UK & EUROPE COVER REVEAL 🎉 🎉 🎉
The Edge of Space-Time is coming to European readers via UK publisher @canongate.co.uk on 7 May 2026! With a slightly different subtitle 😂
Preorders now open! Please support your local indie. It helps authors so much!
buythebook.online/edge-of-spac... #BookSky
The Edge of Space-Time is coming to European readers via UK publisher @canongate.co.uk on 7 May 2026! With a slightly different subtitle 😂
Preorders now open! Please support your local indie. It helps authors so much!
buythebook.online/edge-of-spac... #BookSky
Reposted by Linn Boldt-Christmas
It was great getting to share these exciting results as part of the BOWIE+ seminar series. Ariel has the potential to revolutionise our 3D understanding of exoplanet atmospheres, with a phase curve survey of ~100 targets within its reach. Let’s push to make it happen!
Dan Valentine (@danvalentine.bsky.social) has done some great work looking at using ARIEL to eclipse map exoplanet atmospheres. #exoplanets #astronomy
www.youtube.com/watch?v=lrtL...
www.youtube.com/watch?v=lrtL...
Eclipse Mapping with Ariel: Future Prospects for a Population-Level Mapping Survey
YouTube video by BOWIE+ Seminars
www.youtube.com
December 2, 2025 at 12:11 PM
It was great getting to share these exciting results as part of the BOWIE+ seminar series. Ariel has the potential to revolutionise our 3D understanding of exoplanet atmospheres, with a phase curve survey of ~100 targets within its reach. Let’s push to make it happen!
Reposted by Linn Boldt-Christmas
Interesting journal club with the Exoplanets group at @physicsuol.bsky.social, looking at the transition from giant planets to brown dwarfs (arxiv.org/abs/2511.11818). They don't mention it, but is the gap at 2-3 MJ & [Fe/H]~0.2 called anything?
If not, I'm calling it the Leicester doughnut hole 🔭
If not, I'm calling it the Leicester doughnut hole 🔭
![Plot of companion mass vs [Fe/H] from the linked paper. There's a hole around 2 Jupiter masses and 0.2 dex.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:ruytv26vgniv4gshs37toqeu/bafkreiauxafy7bfpn6jz6tueunbqovvayj4n3kra4qjfusid64ntxljeke@jpeg)
December 2, 2025 at 1:42 PM
Interesting journal club with the Exoplanets group at @physicsuol.bsky.social, looking at the transition from giant planets to brown dwarfs (arxiv.org/abs/2511.11818). They don't mention it, but is the gap at 2-3 MJ & [Fe/H]~0.2 called anything?
If not, I'm calling it the Leicester doughnut hole 🔭
If not, I'm calling it the Leicester doughnut hole 🔭