John Debes

@johndebes.bsky.social

1331 Followers 488 Following

ESA/AURA astronomer at STScI. Opinions my own. I study exoplanets and disks around stars.

A thermometer reading 40 C or 104 F
An Oriole perched on a rainbow O
A Star Trek TNG title card that says “Staff Meetings with Explosions”
A glass award with “AURA Team 2026 Outstanding Achievement Award: The Hubble Spectroscopic Legacy Archive Team
FIRST robotics field showing robots and the competition field including yellow foam balls, fuel intakes and various obstacles
A cute dog with flurry rabbit ears looks up to the camera
Dozens of mirror reflections of a man with a backpack and a name tag
A Pitt mix dog with a blurred tongue and mouth. She is cookoo for any treats you might have
A figure showing the two MIRI photometry excess fluxes as a function of wavelength. Overplotted are three spectra. The first is a warm debris disk located at the tidal disruption radius with a red line. It matches the 15 micron flux but not the 10 micron flux. The second is a blue line representing a cooler debris disk located at 0.02au. It fits both fluxes. The third line is pink and represents a cold disk at roughly the asteroid belt location. It fits the 15 micron flux but not the 10 micron flux. Finally an orange line represents a cloudless giant planet SED. Both the 10 and 15 micron fluxes are consistent with a 260K substellar object around 6 Mjup given the age of the white dwarf.
Two panel figure showing the detection of Ca in 1999 (upper panel) and 2025, with the Keck HIRES spectrograph. Interestingly, the RV of the lines is similar to within 0.5 km/s over 25 years. That's a good archival wavelength solution!
False three color image using MIRI F1000W and F1500W filters (10 and 15 microns wavelength). At the center is the white dwarf and surrounding it are a variety of background objects with different apparent colors. A circle encompasses a projected separation of 200 au. The image is oriented North up East left.
A man sitting dressed in the style of lower decks. He is a lieutenant commander
A Star Trek science officer in the style of the show Lower Decks. He is seated in a conference room on a starship
A NIR CO spectrum taken with NIRSPEC G395H covering 4.46-5.06 micron. The spectrum shows a forest of interesting CO lines as well as evidence of self-absorption.
A UV spectrum stretching from 1150 Angstroms all the way to nearly 3100 Angstroms, showing an A star SED with flux that ranges over four orders of magnitude and with a forest of absorption features. Three lines show that this spectrum was constructed from COS G130M data, STIS E140H data, and E230H data.
Graphic from https://science.nasa.gov/asset/hubble/stis-records-a-black-holes-signature/. The left panel shows an image of the M84 galaxy, while a light blue rectangle denotes where STIS observed the M84 nucleus with its slit. The right panel shows a rainbow "S" shaped squiggle. Spatial information is vertical, while the S traces a large deviation in velocity along wavelength. It measures the fast velocities of gas orbiting an unseen massive black hole that drives a central accretion disk.
A UV spectrum of PDS 70, a young star. The spectrum shows several emission lines, most prominently for Mg II at 2800 Angstroms.
A two panel spectrum. The top panel shows a spectrum from 930 Angstroms to 990 Angstroms, revealing several ISM hydrogen lines. The bottom panel shows a spectrum with high signal to noise, along with sharp spectral absoprtion features.
The logo for the Cosmic Origins Spectrograph, an instrument on Hubble that takes UV spectra.
A logo "HSLA" which stands for Hubble Spectroscopic Legacy Archive, has three stylized spectra with rainbow colors radiating from left to right. In the background are stars, galaxies, and a giant planet.
A graph showing flux density in Janskys as a function of wavelength for a white dwarf on the top, and a comparison between the observed photometry and predicted flux from a white dwarf atmospheric model in the bottom panel. Red x's show the predicted photometry from the model, the black solid line is the predicted spectrum of the white dwarf, and black squares are the observed photometry. grey circles with errorbars are SPHEREx spectrophotometry. In the bottom panel the blue squares are the new JWST MIRIR photometry. For this target, EVERYTHING matches really well. Like shockingly well.
A false color image of the JWST MIRI field of view. The white dwarf is a blue point source roughly in the middle of the image, surrounded by blue and orange stars and galaxies.
A screen shot of the ADS entry for Debes & Sigurdsson, 2002: Are there Unstable Planetary Systems around White Dwarfs? ADS records that the paper has been cited 400 times.
The cover to Weird Al’s first album. He was hugely instrumental in showing me it was ok to be goofy and nerdy without shame. And that you don’t have to fit in if you don’t want to.
Matt Bomer as Neal Caffrey on White Collar.
Luna the dog resting her head on a yellow pillow
A dawn sky reveals stars and two bright planets
A figure that shows CGI expected perfomance, current performance of ground- and space-based observatories.
An image of the Roman CGI Hybrid Lyot Coronagraph dark hole after ADI reduction. A color bar denotes contrast per pixel. The field of view is roughly at the 10^-8 or lower level.
A grey tabby with white boots, and the fluffiest and most inviting belly. He is gazing down in a sleepy expression
A cactus taco, a carnitas taco with pork rinds, and a cricket and guacamole taco. All of them are on blue corn tortillas and are delicious
A presentation showing an example of how the Roman Space Telescope coronagraph will help to demonstrate HWO technology. A bright star looks for a planet by using coronagraphy and a reference star that helps get rid of the telescope diffraction
A very teen wren baby peeking out of a tangled nest
Images of the TW Hya disk from NASA/STScI showing the presence of one shadow seen in 2016 and a series of two shadows seen in 2021. After five years a new shadow had appeared and the shadow seen in 2016 had moved from roughly the 10 o'clock position on the sky to the 7 o'clock position.
A long hair grey cat with a white collar has had enough of your nonsense displaying toe beans on her right paw
Image of a giant planet orbiting close to a white dwarf star from: https://exoplanets.nasa.gov/news/1657/nasa-missions-spy-first-possible-survivor-planet-hugging-a-white-dwarf-star/
A planet being evaporated near a large red star. originally from https://science.psu.edu/news/scientists-discover-new-planet-orbiting-dangerously-close-giant-star
This is the same figure as the previous post, go there for more info!
Two plots of the excess flux from the white dwarfs compared to model dust disks and planets. The yellow squares are the planet fluxes, while the red, blue, and pink lines represent three types of somewhat plausible dust disks. The red line corresponds to a very faint warm disk that doesn't match the data very well. The blue line comes from a disk at just 0.05 au, but outside where you'd expect dust to reside. Finally a very cold and massive dust disk is represented by the pink line--this kind of dust disk would be a very massive version of our asteroid belt.
Spectral energy distribution for WD 2105-820. We measure the brightness of the white dwarf from the UV to 21 microns with JWST. The top panel shows the measurements (black and blue squares) compared to predictions from a model (red asterisks). The model spectrum at high spectral resolution is represented by a black line. Most squares line up with the models. The bottom panel shows how significant any deviations from the model at each wavelength are. A red line denotes 0, and dashed lines show a deviation of +/-3x the uncertainties. The 21 micron point deviates positively by 5.6x the uncertainties in the model and photometry, indicating a signficiant excess of flux.
A spectral energy distribution of WD 1202-232, a white dwarf that is actively accreting dust from asteroids. We measure the brightness of the white dwarf from the UV to 21 microns with JWST. The top panel shows the measurements (black and blue squares) compared to predictions from a model (red asterisks). The model spectrum at high spectral resolution is represented by a black line. All the squares mostly line up with the models. The bottom panel shows how significant any deviations from the model at each wavelength are. A red line denotes 0, and dashed lines show a deviation of +/-3x the uncertainties. Any thing beyond 3-5x the uncertainties is indication of a significant deviation.
Images at four wavelengths for WD 2105-820, a nearby white dwarf with metal pollution from rocky dust. At about 2 o'clock is a faint source that might be a planet. Other stars and galaxies dot the field of view, most of them getting brighter at longer wavelengths.
A lost pet sign depicting a cheetah beanie baby. “Goes by the name Freckles”
A UV spectrum of VV Cephei during total eclipse, where a hot stellar companions is illuminating the wind of an M super giant (See Bauer, Bennet & Brown, 2007). HASP takes many different spectra and joins them together in a robust way for easy science. The top spectrum shows all the different orders of a STIS echelle observation, where the orders often overlap. The HASP spectrum joins them all together into a single easy to interact with spectrum for the first time.
The logo for the Hubble Advanced Spectral Products, or HASP. White lettering with a rainbow border below. To the right is a set of stylized spectra ranging from violet to red that are in the process of "hooking" together. A hasp is a latching mechanism, which is similar to what HASP does--link different gratings from HST spectroscopy together.
A cute grey tabby nuzzles my hand next to a computer
A view of the Wolf Trap stage. It’s crowded and I have shit seats but let’s be honest: I just am happy to hear the guy.
Images of two white dwarfs, denoted by blue stars with small barely detected points that are the candidate planets, circled in red. A scale bar denotes 2 seconds, which is about 0.1% the size of a full moon. Both candidates are as close or closer than the scale bar length, corresponding to 11 au for the top candidate and 34 au for the bottom candidate
A brindle dog laying down obstinately when she should be walking
This is my first lemon pig inspired by Alex Plante.i think that’s who it is, I’m sorry I’m going off of shoddy memory. Anyways, this lemon pig is struggling, as if he had absorbed all of the shit directly from the US government, like it might have been worse if he hadn’t borne the full brunt of fascist assholery. He’s missing an eye, he is barely grasping onto his coin. He is bowed down like a citron atlas, scarred and desiccated from unelected billionaires. Even his foil tail has lost its sheen.
A dusk shot of lava erupting from a crater in Kilauea. The iPhone makes it look like Mt. Doom
A sports car with a black She-go character and “Savage” on the side
A SWATCH brand watch with the ESA logo (European Space Agency) the watch face is clear with gears and the band has a JWST image of the pillars of creation
A graph showing disk mass (M_disk) vs. disk inner radius (R_in). the observations show that most disks reside at ~1-1.5x the Roche radius, consistent with the predictions of the Kenyon & Bromley models.
A graph showing the inferred disk mass as a function of WD accretion rates. The observations favor massive bodies (>=300 km) as the inputs to collisional cascades.
Three people standing by an AAS iPoster at the 245th AAS meeting. Ash Messier stands in the middle, and John Debes is on the right. The poster talks about looking at white dwarfs with dust disks and comparing them to predictions of collisional cascade models.
An infographic for Gaia showing the hat shaped satellite on a backdrop of a model of the milky way derived from Gaia data: 3 trillion obserations, 2 billion stars and other objects, 938 million camera pixels on board, 15300 spacecraft "pirouettes", 55 kg of cold nitrogen gas consumed, 3827 days in science operations, 580 million accesses of the catalog so far, 13000 refereed publications so far, 2.8 million commands sent to spacecraft, 142 TB downloaded data (compressed), 500 TB volume of data release 4 (5.5 years of observations, and 50000 hours of ground station time used. Whew!
A list of talk titles for Thursday Jan 16, 2025 at 2-3:30 pm in Potomac Ballroom C: Multi-Star Wavefront Control at the Occulting Mask Coronagraph... by Marx et al. Direct Detection of Silicate Clouds in a Multiplanet System... by Hoch et al. Ground and Space Synergies in Direct Imaging Studies of Exop... by Girard et al. Demonstrating Sensitivity to Exo-Saturns around Nearby Young.... by Bogat et al. Mid-IR Excess Reveals a Giant Planet Candidate Around a White Dwarf by Limbach et al. A Comparative Analysis and Optimization of Thrust Capabilities... by Shaklan et al. Medium-resolution mid-IR Spectroscopy of the cold directly imaged planet... by Malin et al. AND! Metal Polluted White Dwarfs with 21-micron Excesses: Dust or Planets? by Debes et al.
Rudy Giuliani, ostensibly holding up a watch off camera taken from a CNN article, but clearly also staring into the abyss of his poor life choices
A sleepy doggie under a warm blanket