Nienke van der Marel
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nienkemarel.bsky.social
Nienke van der Marel
@nienkemarel.bsky.social
Assistant professor of astronomy at Leiden Observatory | Leiden University | Formerly 🇨🇦&🇺🇲 | Planet formation | ALMA | Astromom | Outreach | She/her/hers | Views my own
Pinned
Super proud of my PhD student Osmar who discovered that the so-called 'compact disks' around young stars are REALLY REALLY small! Look at the full sample of Lupus disks, observed at 30 mas resolution with ALMA.
Protoplanetary discs are much smaller than previously thought
www.astronomie.nl
Interview on the Chicken or Egg problem of planet formation on Forbes!

www.forbes.com/sites/bruced...
Planet Formation Theory Is Still Ensnared By A Chicken Or Egg Problem
Astronomers still debate how solar systems like ours could form planets like our own.  How the very first planet formed has created a bit of a chicken or egg conundrum.
www.forbes.com
August 6, 2025 at 3:42 PM
There is now a planetesimal bearing my name!! Nice to meet you 6054 P-L!
And thank you IAU for making it happen.

www.astronomie.nl/nieuws/17-ni...
17 nieuwe ‘Nederlandse’ planetoïden
www.astronomie.nl
July 22, 2025 at 9:47 AM
Today was supposed to be a strike in the Netherlands on behalf of the higher education, against the major budget cuts. I think it got mostly cancelled due to the (completely coincidental) national train strike, but I was still wondering: is a strike the best way to protest as academics?
June 10, 2025 at 3:25 PM
Reposted by Nienke van der Marel
📣 Calling all rocky enthusiasts! We are thrilled to announce that the ROCKY WORLDS 4 Conference will take place 19-23 Jan 2026 in Groningen, NL 🇳🇱 This is the 4th Meeting in our series & we can't wait to see you there!

Abstract submission is NOW OPEN groningen2026.rockyworlds.org/groningen-2026

🪐☄️🔭
June 10, 2025 at 12:20 PM
Reviewing a proposal that cites one of my four 2021 papers. I checked the reference to see which one it is and the volume and page do not correspond to any of my papers. I asked ChatGPT and it claims is van der Marel & Mulders 2021 with a different volume and page. Did I reverse-engineer ChatGPT?
May 31, 2025 at 8:50 AM
Tomorrow I will be at a 'talk show' on the great outdoors organized by TU Delft, talking about stories from observing nights at high altitude.
April 28, 2025 at 8:42 AM
Winner of two prizes at the Leiden Allegro ARC node competition, both the one for most requested hours (of all proposals combined) and for the smallest proposal 😁 #almacycle12
April 24, 2025 at 5:58 PM
The usual curve of proposal submissions on ALMA deadline day. It looks like we may end up a bit lower than last Cycle, unless we get a final sprint. I'm going to bet on 1560. What's your guess?
#almacycle12
April 24, 2025 at 1:57 PM
Looks like we are somewhat below the trend of last year. How many people are still submitting in the final 10 hours? #almacycle12
April 24, 2025 at 5:13 AM
It is that time of the year again:
#almacycle12
April 22, 2025 at 8:03 AM
Really happy that three of my master students have managed to get a PhD position this year! Curious to see where their research is going to bring them 💪
March 31, 2025 at 5:44 PM
Reposted by Nienke van der Marel
here's my story on the (largely dutch) discovery that most protoplanetary disks are small and may spawn super-earths (for the website of sky and telescope): 🔭
skyandtelescope.org/astronomy-ne...
Tiny Disks Shed Light on Super-Earth Origins
A team of astronomers has obtained high-resolution images of all known protoplanetary disks in the Lupus star-forming region.
skyandtelescope.org
March 28, 2025 at 8:46 PM
Exactly! Always consider the biases in your sample.
A lot of cosmic exploration centers around "what's weird?" & "what's normal?"
Early studies of young stars showed an abundance of huge planetary systems forming. New observations show the opposite: Lots of small systems, much more compact than our solar system. 🧪🔭

www.astronomie.nl/nieuws/en/pr...
March 27, 2025 at 5:59 AM
To accompany the press release from this morning on the compact disks, I made a short 2 minute video that showcases the key result. Enjoy watching!

youtu.be/jvT1wD7yCec
How does a typical protoplanetary disk look like?
YouTube video by Nienke van der Marel
youtu.be
March 26, 2025 at 12:29 PM
Reposted by Nienke van der Marel
Protoplanetaire schijven zijn veel kleiner dan eerder gedacht.

Door Universiteit Leiden geleid onderzoek van Osmar M. Guerra-Alvarado et al., geaccepteerd voor publicatie in A&A.

www.astronomie.nl/ni...

March 26, 2025 at 7:01 AM
Super proud of my PhD student Osmar who discovered that the so-called 'compact disks' around young stars are REALLY REALLY small! Look at the full sample of Lupus disks, observed at 30 mas resolution with ALMA.
Protoplanetary discs are much smaller than previously thought
www.astronomie.nl
March 26, 2025 at 7:17 AM
Help! The arxiv submission e-mail suddenly states that it may take 2 business days to go through technical/moderation checks. I thought this was always just 1 day. How long did it take you to get accepted on arxiv recently? I'm freaking out because this has to coincide with a press release tomorrow.
March 25, 2025 at 10:08 AM
Reposted by Nienke van der Marel
Le Monde reporting that a French scientist traveling to Houston to attend a conference was denied entry to US after a search of his phone & computer revealed messages critical of Trump's science cuts, "which [says CPB] conveyed hatred of Trump & could be qualified as terrorism". Computer confiscated
March 19, 2025 at 6:11 PM
I've just turned down an invitation for an event in the US this summer as well. There were multiple reasons, including visa appointment issues, but reading the answers on this thread I think I made the right decision: I would not want to go through ridiculous US customs questioning right now.
With everything happening in the US right now, how safe are scientific conferences for foreign participants in the US? I think this is something we have to discuss as a scientific community. I am hesitating to register for US meetings due to the unpredictable situation. Others who feel the same?
March 19, 2025 at 10:46 AM
Reposted by Nienke van der Marel
Do #exoplanets evolve over time? ☄️

A thread 1/🧵
March 17, 2025 at 10:39 PM
This Fall we will offer a minor in astronomy at Leiden Observatory! It will be accessible for all non-astronomy Dutch BSc students. This program offers a unique opportunity to explore astronomy’s role in shaping our understanding of the Universe. See studiegids.universiteitleiden.nl/studies/1063...
Our Universe (Minor 2025-2026) - Studiegids - Universiteit LeidenLink naar Our Universe in het actieve academische jaar
studiegids.universiteitleiden.nl
March 18, 2025 at 9:00 AM
My BSc students have been digging the ALMA archive and have classified all unresolved low SNR detections as 'disappointing blobs'. 😂
March 17, 2025 at 2:20 PM
Reposted by Nienke van der Marel
🚨 ESO analysis confirms that the INNA industrial megaproject would have a devastating and irreversible impact on the facilities at Paranal Observatory.

Full story ➡️ www.eso.org/public/news/...
Details in 🧵 below 👇
🧪 🔭 #astrosci 1/
New ESO analysis confirms severe damage from industrial complex planned near Paranal
An in-depth technical analysis by the European Southern Observatory (ESO) has evaluated the impact of the INNA megaproject on the facilities at the Paranal Observatory, Chile — and the results are ala...
www.eso.org
March 17, 2025 at 12:00 PM
Are we tired yet of PDS70? It's obviously the topic of many talks at the GAP (Giant Accreting Planets) conference. Nice cartoon by Luna Rampinelli!
March 12, 2025 at 9:57 AM
Reposted by Nienke van der Marel
One of the employees fired from NASA told me how much their career meant to them: "Prior to everything happening today, NASA has been an incredible place to work — to dream big, to innovate, to do things that I never thought I could have done.”

Words by me. 🧪

www.nature.com/articles/d41...
NASA begins mass firings of scientists ahead of Trump team’s deadline
Top advisers in the Office of the Chief Scientist are among the first to go amid downsizing effort.
www.nature.com
March 11, 2025 at 1:13 PM