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Kevin Hardegree-Ullman

@kevinkhu.bsky.social
2.9K followers 266 following 444 posts

Research Scientist at Caltech/IPAC-NExScI studying all things related to exoplanets! Opinions are my own. kevinkhu.com

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Reposted by Kevin Hardegree-Ullman
Dr. Jessie Christiansen @aussiastronomer.bsky.social · 30/09/2026
On point B, the NASA Exoplanet Archive typically serves ~10-20TB of data per month. In July it jumped to 70TB. In August it jumped to 600TB. So either our user base organically grew *30x* in two months (... unlikely), OR the bots have taken over already.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 29/09/2026
This is the first time I've seen polycyclic aromatic hydrocarbons (PAHs) written out in a non-astronomy context. 🔭 #SpaceDust 🌌
Sign on a fence at a park that says: "THIS SITE CONTAINS SOILS THAT CONTAIN THE FOLLOWING CHEMICALS: [LEAD][CHROMIUM VI] [DIOIN] [POLYCYCLIC AROMATIC HYDROCARBONS] TO REPORT ANY DUST LEAVING THE SITE PLEASE CALL (name/number blurred) OR THE SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT AT (number blurred)"
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 27/09/2026
I've been thinking about these points a lot lately with the rise of AI/LLM use recently.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 23/09/2026
So happy for my friend Allison who got to name this asteroid and meet the asteroid's namesake! 🔭🪗 Now if #exoplanets could catch up with asteroids on the naming front...
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 21/09/2026
AI anything should always be user needs to opt-in by default. AI companies know if they had to ask for consent, abide by copyright laws, etc. their models would be significantly less effective. Things like GitHub enabling using your data by default make me want to be less open with things like code.
Screenshot of GitHub copilot AI settings. These are both enabled by default.
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Reposted by Kevin Hardegree-Ullman
Kevin Hardegree-Ullman @kevinkhu.bsky.social · 18/09/2026
This is an ultra cool result from @bemiles.bsky.social and team! The brown dwarf community has wanted to get time-series spectra since Spitzer data revealed near ubiquitous broadband variability. TACs take notice, we should study the weather on more brown dwarfs! 🔭
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 18/09/2026
This is an ultra cool result from @bemiles.bsky.social and team! The brown dwarf community has wanted to get time-series spectra since Spitzer data revealed near ubiquitous broadband variability. TACs take notice, we should study the weather on more brown dwarfs! 🔭
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 15/09/2026
4yo: "Daddy, can I have candy?" Me: "Fine." 4yo: "I want the one that looks like bacon." Me: 🤨 "You mean Twizzlers?" 4yo: "Yes, Twizzlers look like bacon." 🥓
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 10/09/2026
In #exoplanet transit land, we often seek planets further out in their orbit. In direct imaging land, it's all about pushing closer in. This new study from @caltechipac.bsky.social VGSRF @jayke.io finds a new close-in candidate in the classic HR 8799 system!
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Reposted by Kevin Hardegree-Ullman
Kevin Hardegree-Ullman @kevinkhu.bsky.social · 07/09/2026
My older sister Emily has been Colorado State University's sole astronomer for the past decade! She has shared our family's love for space with thousands of students and the Northern Colorado community through her classes and outreach. She really is the best teacher! 🔭 collegian.com/articles/sci...
collegian.com
Physics professor leads CSU astronomy, shares love for the stars
The Rocky Mountain Collegian Science
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 07/09/2026
My older sister Emily has been Colorado State University's sole astronomer for the past decade! She has shared our family's love for space with thousands of students and the Northern Colorado community through her classes and outreach. She really is the best teacher! 🔭 collegian.com/articles/sci...
collegian.com
Physics professor leads CSU astronomy, shares love for the stars
The Rocky Mountain Collegian Science
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Reposted by Kevin Hardegree-Ullman
Kevin Hardegree-Ullman @kevinkhu.bsky.social · 07/09/2026
On this soggy summer's eve, just shy of spooky season, the spotted orb-weaver silently sits at the center of its sizable silky web. 🕷🕸
A spotted orb-weaver spider sitting at the center of a web. The spider has spiky/furry legs and is an orange-brown color.A spotted orb-weaver spider sitting at the center of a large oval-shaped web built under a porch awning. The web is about 40 centimeters wide and 60 centimeters tall. Shrubs cast large shadows on the grass.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 07/09/2026
On this soggy summer's eve, just shy of spooky season, the spotted orb-weaver silently sits at the center of its sizable silky web. 🕷🕸
A spotted orb-weaver spider sitting at the center of a web. The spider has spiky/furry legs and is an orange-brown color.A spotted orb-weaver spider sitting at the center of a large oval-shaped web built under a porch awning. The web is about 40 centimeters wide and 60 centimeters tall. Shrubs cast large shadows on the grass.
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Reposted by Kevin Hardegree-Ullman
Nature Astronomy @natastron.nature.com · 31/08/2026
Agentic research is oxymoronic ☄️
dlvr.it
Agentic research is oxymoronic
Nature Astronomy, Published online: 31 August 2026; doi:10.1038/s41550-026-02954-yThe use of agentic large language models obviates human interpretation of scientific results, and will lead to substantial distrust in the literature.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 30/08/2026
I am thrilled about the successful Nancy Grace Roman Telescope launch this morning! I am, however, disappointed at the significant and often uncredited mission gen-AI, including a disgraceful AI video+song about Roman shown by NASA yesterday. It tells me people don't value artists and their art.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 21/08/2026
It is Tucson hot today in Pasadena 102°F/39°C! At least Tucson usually gets monsoons this time of year. No rain in sight here. 🥵
A temperature reading from an LCD screen that says 102 degrees Fahrenheit.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 21/08/2026
Almost every time an #exoplanet news article comes out...
The Simpsons cartoon bus driver meme where the top panel is a guy driving a bus with the text "Don't make me tap the sign." The bottom panel is a hand pointing to a sign that reads "Sorry, but we still know of zero 'Earth-like' exoplanets."
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 21/08/2026
In recent years, Astronomy on Tap events have grown, hopefully reaching audiences that wouldn't normally go to public talks. However, as an astronomer who doesn't drink and has exactly zero interest in doing outreach at bars, are there other creative outlets you've seen for non-standard outreach? 🔭
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 21/08/2026
PSA: If you've recently served on NASA or NSF panels (especially dual anonymous panels), please comply with the panel guidelines and DO NOT state the panel you served on in your CV! You can say you have served on NASA/NSF panel(s) and which year(s), but please don't be more specific than that. 🔭🧪
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 19/08/2026
Excited that a group is doing homogeneous characterization of a large sample of stars for radial velocity targets. A uniform stellar catalog is the first crucial step in exoplanet demographics! arxiv.org/abs/2608.17734
arxiv.org
A Catalog of Homogeneously Derived Stellar Parameters for Spectroscopic Survey Stars
Uniformly derived stellar parameters are vital for exoplanet demographic studies because they directly influence the inferred planetary masses, radii, and bulk densities. This study presents a new hom...
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 17/08/2026
Sometimes I miss this telescope. 🔭
A sidewalk with the name SPITZER spray painted on the side in black stencil lettering with a white background.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 13/08/2026
Apparently work never stops, even when on vacation. It took 3 of us 3 partial days to remove this side of the old roof and re-shingle. Luckily, this time we had a nail gun. ~10 years ago we replaced the other side and there were only 2 of us and we had to hammer every single nail.
A white guy in a long white t-shirt, a gray floppy bucket hat, and wearing black gloves and sunglasses. He is reaching over to adhere shingles to a roof with a nail gun.A newly installed roof on the back side of a garage. Two small windows are visible in a small inset in the garage and yellow lights shine from inside. A bunch of green trees are in the background. A black car is visible in the middle right.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 05/08/2026
Peahen timeline cleanse featuring 4 baby peachicks! 🦚
A peahen and her four baby peachicks looking for food on green grass. A short brick wall and some plants are in the background.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 04/08/2026
Just two weeks before school starts, I learn that the public school has a uniform* policy. I guess I'll have to join the PTA now to try to get that changed. 🫠 *not a uniform, but kids can only wear plain school color shirts and tan or blue pants/shorts 4 days a week.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 04/08/2026
Ugh. I only learn 2 weeks before school starts that the public elementary school has a uniform policy. 🫠
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 04/08/2026
My 4-year-old is gonna love this.
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Reposted by Kevin Hardegree-Ullman
Kevin Hardegree-Ullman @kevinkhu.bsky.social · 30/07/2026
In public, I generally want to minimize human interaction (e.g., self checkouts should be everywhere and allow more than 10 items). But if I actually need to use a phone the way they were intended, I absolutely expect a human to answer and not some bullshit AI assistant.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 30/07/2026
Did anyone of the Windows 9x generation have Microsoft Encarta and play MindMaze? Most of my 90s computer memories were of edutainment games like MindMaze, Spelling Jungle, Museum Madness, and Challenge of the Ancient Empires.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 30/07/2026
In public, I generally want to minimize human interaction (e.g., self checkouts should be everywhere and allow more than 10 items). But if I actually need to use a phone the way they were intended, I absolutely expect a human to answer and not some bullshit AI assistant.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 29/07/2026
It took all my self control to not burst out laughing the other day when somebody in the doctor's office waiting room kept asking someone on the phone if "fart-ciga" was the drug they needed to ask the doctor about.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 26/07/2026
Netflix has always been terrible at suggesting things to watch. Now we know why. Time to drop Netflix.
Netflix showing suggestions based on astrology. Their algorithm is clearly BS now.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 22/07/2026
Michelle Kunimoto pointing out the importance of *automated* vetting of #exoplanet candidates. Manual inspection introduces uncharacherizable biases! #Sagan2026
A zoom presentation from Dr. Michelle Kunimoto discussing the Lazy-Exoplanet-Operations Vetter (LEO-Vetter) and the importance of automated exoplanet vetting for exoplanet demographics.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 21/07/2026
All Roman transiting #exoplanet demographics will require a uniform stellar catalog. Check out Ashley Elliott's #Sagan2026 poster about the Roman GBTDS All-Star Catalog!
A conference poster for the Sagan 2026 Workshop for The Roman Galactic Bulge Time Domain Survey All-Star Catalog.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 21/07/2026
#Sagan2026, we have more responses to the *interactive* poster, don't forget to add your own thoughts!
A conference poster for the Near-Infrared Transit Explorer (NITE).
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Reposted by Kevin Hardegree-Ullman
Dr. Alison Duck @astroalison.bsky.social · 20/07/2026
#Sagan2026 is off to a great start!! We have many amazing posters everyone should check out! And if you are curious about designing your own poster the video recording of my PROTO session “Communication Tips & Tricks for Posters and Pops” is live on YouTube! youtu.be/1V4c64xlr7M?...
youtu.be
PROTO: Tips and Tricks for Effective Communication with Scientific Posters
YouTube video by Sagan Summer Workshop
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 20/07/2026
If you're at #Sagan2026, come check out my *interactive* #exoplanet poster! The Near-Infrared Transit Explorer (NITE) is a survey mission concept designed to find Earth-sized planets in the habitable zones of M dwarfs!
A conference poster for the Near-Infrared Transit Explorer (NITE), and exoplanet surve mission concept focused on M dwarf habitable zone planets.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 18/07/2026
This is funny to come home to for a split second before you realize what they got into. #DogShaming
A black and white rat terrier dog with their head through the handle of a dark blue Ghirardelli chocolate bag.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 17/07/2026
Sounds like we need a mission dedicated to finding more habitable zone rocky planets around nearby M dwarfs! At least one has an atmosphere, there's bound to be more (and hopefully some closer to Earth size/mass)!
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Reposted by Kevin Hardegree-Ullman
Dr. Jake Turner 📡🧲🪐 @astrojaket.bsky.social · 16/07/2026
⭐Another new paper! ⭐🔭 Proud Advisor Moment 🤗 Skylar, my PhD student, just had their first PhD paper accepted for publication! They did a fantastic job 😀 We update the orbit of the sub-Neptune pi Men c and find evidence of another planet 👀 Paper here for free: arxiv.org/abs/2607.12088
arxiv.org
TESS Photometry and Radial Velocity Analysis of the sub-Neptune Exoplanet π Mensae c and the Wider π Mensae Planetary System
Exoplanet characterization relies on precise measurements of planetary orbital and physical parameters. This is particularly important for planetary dynamics and atmospheric evolution, as orbital para...
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 10/07/2026
We had three very nice (partial) nights on IRTF earlier this week, so of course our last night of this semester is not very good. It also kinda looks like a big twirly storm is brewing south of Hawaii. 🔭😶‍🌫️🌀
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 01/07/2026
Having an inquisitive 4 year old with an expanding vocabulary is great. Dictionary dad mode unlocked.
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 29/06/2026
I am very excited to see this Spitzer Y dwarf variability paper out! We are studying weather on the coldest brown dwarfs that are close cousins of Jupiter! #exometeorology #astronomy #exoplanets 🔭 arxiv.org/abs/2606.26411
arxiv.org
A Spitzer Space Telescope Exploration Science Program to Search for Y Dwarf Variability
We present the results of a Spitzer Space Telescope Exploration Science Program to search for and characterize variability in Y dwarfs. We observed 14 Y dwarfs over a 24 hr period at [3.6] and [4.5] a...
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 20/06/2026
I got new glasses a month ago and they have been bothering me with extra reflections and glare. Today I realized the edge of the lenses are polished rather than frosted. I've never had that issue before with my glasses. Would not recommend. #Optics
Two pairs of glasses on a wooden surface. The brown glasses on the left have lenses with a frosted edge. The black pair of glasses on the right have lenses with a polished edge.
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Reposted by Kevin Hardegree-Ullman
Caltech IPAC @caltechipac.bsky.social · 17/06/2026
Are you ready to P A R T Y #AAS248? 🥳 💃 🔭 It’s IPAC’s 40th birthday this year & we’re celebrating with free food, drinks, and #IPAC40 prizes! Grab your “Passport to the Universe” and join us: ⌚️ 6:30-8:00pm 📍 Conference Center Room 106 (bldg opposite of expo hall & downstairs)
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Dr. Jessie Christiansen @aussiastronomer.bsky.social · 17/06/2026
ANOTHER JOB AD! #jobs #exoplanets #aas248 NExScI is advertising for a postdoc to come and join our fabulous team in sunny SoCal. The role involves both programmatic support and independent science research, so it's perfect for someone thinking about a career at NASA!!! aas.org/jobregister/...
aas.org
Postdoctoral Scholar - NExScI | American Astronomical Society
Job Summary Caltech is a world-renowned science and engineering institute that marshals some of the world's brightest minds and most innovative tools to address fundamental scientific questions. IPAC,...
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Dr. Jessie Christiansen @aussiastronomer.bsky.social · 16/06/2026
Hey #AAS248 - don't forget, we have two job ads out at the moment: 1) NASA Exoplanet Archive Staff scientist 🪐✨💾 2) NExScI AI Software developer 🤖💻🌟 Come to the NExScI table in the @caltechipac.bsky.social booth to ask questions! Or find me!
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 15/06/2026
#AAS248 come to Session 119 #Exoplanet I - 2pm - Ballroom A to learn about COUNTESS! 119.01 COUNTESS: Exoplanet Demographics with the TESS Continuous Viewing Zones (me) 119.02 COUNTESS: A Pipeline to Extract the Potential of the TESS Mission for Exoplanet Demographics @brandonradzom.bsky.social
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Reposted by Kevin Hardegree-Ullman
Dr. Jessie Christiansen @aussiastronomer.bsky.social · 15/06/2026
📣 TESS IS A STATISTICS MISSION 📣
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Kevin Hardegree-Ullman @kevinkhu.bsky.social · 15/06/2026
New paper led by Andrew Hotnisky (grad student, University of Florida)! COUNTESS I: A Uniformly Vetted Catalog of Known and New Transiting Exoplanets in the TESS Northern Continuous Viewing Zone arxiv.org/abs/2606.13789 #Exoplanets #AAS248 🔭
arxiv.org
COUNTESS I: A Uniformly Vetted Catalog of Known and New Transiting Exoplanets in the TESS Northern Continuous Viewing Zone
The Transiting Exoplanet Survey Satellite (TESS) has transformed the study of nearby exoplanetary systems; however, its nominal observing strategy limits sensitivity to planets with orbital periods sh...
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