Dr./Prof. Meredith MacGregor
@mmacgreg.bsky.social
Assistant Professor at Johns Hopkins in the Department of Physics and Astronomy | astronomer, educator, runner, mom | Pronouns: she/her
So excited to see our EVE science highlighted in Evgenya Shkolnik’s fantastic plenary at #AAS247! I’m thrilled to be proposing this mission to NASA
January 8, 2026 at 11:26 PM
So excited to see our EVE science highlighted in Evgenya Shkolnik’s fantastic plenary at #AAS247! I’m thrilled to be proposing this mission to NASA
It’s far-infrared day at #AAS247! Come learn about how cool this part of the spectrum is and why it is critical for a multi-wavelength understanding of the universe!
January 7, 2026 at 5:07 PM
It’s far-infrared day at #AAS247! Come learn about how cool this part of the spectrum is and why it is critical for a multi-wavelength understanding of the universe!
Come join us in the session discussing our report on the landscape of undergraduate degrees in astronomy and astrophysics at #AAS247 in room 226B!
January 5, 2026 at 9:03 PM
Come join us in the session discussing our report on the landscape of undergraduate degrees in astronomy and astrophysics at #AAS247 in room 226B!
What a great birthday present today - SMEX is back on! Let’s go EVE!
January 5, 2026 at 6:47 PM
What a great birthday present today - SMEX is back on! Let’s go EVE!
Pretty excited to be part of this awesome team doing super cool science! arxiv.org/abs/2512.07695
JWST TRAPPIST-1 e/b Program: Motivation and first observations
One of the forefront goals in the field of exoplanets is the detection of an atmosphere on a temperate terrestrial exoplanet, and among the best suited systems to do so is TRAPPIST-1. However, JWST tr...
arxiv.org
December 10, 2025 at 2:39 PM
Pretty excited to be part of this awesome team doing super cool science! arxiv.org/abs/2512.07695
Reposted by Dr./Prof. Meredith MacGregor
1/ It's press day!🔭🧪 We apply a grid of time-dependent physical models to explain TRAPPIST-1 flares, predicting the X-ray & UV flux driving escape and photochemistry in planetary atmospheres, and correcting flare contamination in transit spectroscopy down to ~60 ppm:
www.colorado.edu/today/2025/1...
www.colorado.edu/today/2025/1...
New research on flares from a hot-tempered star could inform search for habitable planets
A new study takes a close look at TRAPPIST-1, a little star roughly 40 light-years from our sun that hosts seven Earth-sized planets.
www.colorado.edu
December 4, 2025 at 6:53 PM
1/ It's press day!🔭🧪 We apply a grid of time-dependent physical models to explain TRAPPIST-1 flares, predicting the X-ray & UV flux driving escape and photochemistry in planetary atmospheres, and correcting flare contamination in transit spectroscopy down to ~60 ppm:
www.colorado.edu/today/2025/1...
www.colorado.edu/today/2025/1...
Today is the ExoJamboree at @jhuartssciences.bsky.social and @stsci.edu - How cool is that we are such a powerhouse of exoplanet research here that we can have an awesome conference with just local people?!?!
November 21, 2025 at 7:04 PM
Today is the ExoJamboree at @jhuartssciences.bsky.social and @stsci.edu - How cool is that we are such a powerhouse of exoplanet research here that we can have an awesome conference with just local people?!?!
Another wonderful article about our RZ Psc work!
I was tempted to make this post "Avi Loeb Claims Millions of Spaceships Found" but decided against it.
www.scientificamerican.com/article/alie...
🔭 🧪
www.scientificamerican.com/article/alie...
🔭 🧪
Alien Comets Swarm around Other Stars
Comets don’t just orbit our sun. “Exocomets” are common around other stars in the galaxy, too
www.scientificamerican.com
November 21, 2025 at 2:41 PM
Another wonderful article about our RZ Psc work!
This! Here's a slide pulled from my class lecture notes this semester. Comets have two clear tails - one from dust and one from ions. They point in different directions because one feels the solar wind while the other feels radiation pressure.
November 14, 2025 at 4:03 PM
This! Here's a slide pulled from my class lecture notes this semester. Comets have two clear tails - one from dust and one from ions. They point in different directions because one feels the solar wind while the other feels radiation pressure.
Nature published a research highlight on our RZ PSc exocomet paper: www.nature.com/articles/d41...
A host of ‘exocomets’ swarms a distant star
Dimming of the starlight from RZ Piscium reveals that 24 unseen bodies are whizzing around the star.
www.nature.com
November 11, 2025 at 7:57 PM
Nature published a research highlight on our RZ PSc exocomet paper: www.nature.com/articles/d41...
Flying to Rochester today to give the colloquium. Can confirm that most of security at BWI is shut down and people aren’t happy about it 🫠
November 2, 2025 at 7:38 PM
Flying to Rochester today to give the colloquium. Can confirm that most of security at BWI is shut down and people aren’t happy about it 🫠
So excited that our paper is finally out! We analyzed archival TESS observations of RZ Psc and detected 24 transiting exocomets. And, Adalyn is an amazing undergrad applying for grad school this year!
Gibson et al. “TESS Discovers a Second System of Transiting Exocomets in the Extreme
Debris Disk of RZ Psc” showing 24 exocomet transits and the existence of a broken power law for the sizes of these exocomets, unlike Beta Pic’s exocomet distribution #exoplanet #astrodon #astrosci
Debris Disk of RZ Psc” showing 24 exocomet transits and the existence of a broken power law for the sizes of these exocomets, unlike Beta Pic’s exocomet distribution #exoplanet #astrodon #astrosci
October 14, 2025 at 1:19 PM
So excited that our paper is finally out! We analyzed archival TESS observations of RZ Psc and detected 24 transiting exocomets. And, Adalyn is an amazing undergrad applying for grad school this year!
Calling the Astronomy hive mind! Who is your favorite deceased astronomer that deserves to have something named after them posthumously? And why?
September 11, 2025 at 10:24 PM
Calling the Astronomy hive mind! Who is your favorite deceased astronomer that deserves to have something named after them posthumously? And why?
Reposted by Dr./Prof. Meredith MacGregor
National Radio Astronomy Observatory: Neighboring Star’s Warped Ring Shaped by Evolving Planets public.nrao.edu/news/neighbo...
Neighboring Star’s Warped Ring Shaped by Evolving Planets - National Radio Astronomy Observatory
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have made the highest resolution image to date, revealing new insights...
public.nrao.edu
September 8, 2025 at 2:28 PM
National Radio Astronomy Observatory: Neighboring Star’s Warped Ring Shaped by Evolving Planets public.nrao.edu/news/neighbo...
Super excited that these results are finally out! This is the highest resolution ALMA image of Fomalhaut ever, and we can learn new things about the structure of the disk and the planet that is likely shaping it. Press release here: public.nrao.edu/news/neighbo...
Neighboring Star’s Warped Ring Shaped by Evolving Planets - National Radio Astronomy Observatory
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have made the highest resolution image to date, revealing new insights...
public.nrao.edu
September 4, 2025 at 5:21 PM
Super excited that these results are finally out! This is the highest resolution ALMA image of Fomalhaut ever, and we can learn new things about the structure of the disk and the planet that is likely shaping it. Press release here: public.nrao.edu/news/neighbo...
It's the first day of classes and I spent the weekend in the hospital with a sick little one who needed emergency surgery... Let's do this! (Also, please send coffee!)
a sign that says " what is even happening " next to a dumpster
ALT: a sign that says " what is even happening " next to a dumpster
media.tenor.com
August 25, 2025 at 3:57 PM
It's the first day of classes and I spent the weekend in the hospital with a sick little one who needed emergency surgery... Let's do this! (Also, please send coffee!)
Perfect evening for the department welcome crab feast @jhuartssciences.bsky.social! 🦀
August 22, 2025 at 9:37 PM
Perfect evening for the department welcome crab feast @jhuartssciences.bsky.social! 🦀
Challenge: post your last photo taken in DC to show what a hell-hole it is.
August 12, 2025 at 2:32 AM
Challenge: post your last photo taken in DC to show what a hell-hole it is.
Back for another day of #HWO25 at the stunning at the @jhuartssciences.bsky.social Bloomberg Center!
July 29, 2025 at 12:30 PM
Back for another day of #HWO25 at the stunning at the @jhuartssciences.bsky.social Bloomberg Center!
Wow wow wow 🤩 It’s just amazing what we humans can do when we support scientific research and funding
Introducing...your sneak peek at the cosmos captured by NSF–DOE Vera C. Rubin Observatory!
Can you guess these regions of sky?
This is just a small peek...join us at 11am US EDT for your full First Look at how Rubin will #CaptureTheCosmos! 🔭🧪
#RubinFirstLook
ls.st/rubin-first-look-livestream
Can you guess these regions of sky?
This is just a small peek...join us at 11am US EDT for your full First Look at how Rubin will #CaptureTheCosmos! 🔭🧪
#RubinFirstLook
ls.st/rubin-first-look-livestream
June 23, 2025 at 12:38 PM
Wow wow wow 🤩 It’s just amazing what we humans can do when we support scientific research and funding
Great article, @hannah-richter.bsky.social!
The White House's proposed budget for NASA is "a whole new level of horror," according to one planetary scientist. 🚀❌ Read how the space science community is reeling and dealing in my new story for @skyandtelescope.bsky.social #nasa #trump skyandtelescope.org/astronomy-ne...
Proposed NASA Budget Would Gut Space Science, Jobs
With more than 40 missions on the chopping block, the space community is holding on to hope that the budget is “dead on arrival” in Congress
skyandtelescope.org
June 3, 2025 at 7:12 PM
Great article, @hannah-richter.bsky.social!
The report from our AAS Task Force on Graduate Admission is out! This has become a complicated problem in recent years, and is made even worse with the recent federal budget. You can read the report here: arxiv.org/abs/2505.09759
AAS Graduate Admissions Task Force: Final report and recommendations
In March of 2024 the AAS formed our Graduate Admissions Task Force (GATF), asking us to produce recommendations aimed at improving the state of graduate admissions in astronomy. The task was a timely ...
arxiv.org
June 2, 2025 at 2:54 PM
The report from our AAS Task Force on Graduate Admission is out! This has become a complicated problem in recent years, and is made even worse with the recent federal budget. You can read the report here: arxiv.org/abs/2505.09759
The NSF hasn't fared any better including completely eliminating postdoctoral fellowships. I was an NSF AAPF. That program is responsible for me getting to where I am now. We will lose so many early career scientists because of this.
nsf-gov-resources.nsf.gov/files/00-NSF...
nsf-gov-resources.nsf.gov/files/00-NSF...
nsf-gov-resources.nsf.gov
May 30, 2025 at 9:02 PM
The NSF hasn't fared any better including completely eliminating postdoctoral fellowships. I was an NSF AAPF. That program is responsible for me getting to where I am now. We will lose so many early career scientists because of this.
nsf-gov-resources.nsf.gov/files/00-NSF...
nsf-gov-resources.nsf.gov/files/00-NSF...