John Debes
@johndebes.bsky.social
ESA/AURA astronomer at STScI. Opinions my own. I study exoplanets and disks around stars.
Friday HSLA spectrum! My friend Beta Pictoris, first star to have its debris disk imaged and including STIS data I worked on as an undergrad, eleven programs in all. It has two planetary companions more massive than #Jupiter #astrosci #exoplanets 🔭
November 21, 2025 at 4:39 PM
Friday HSLA spectrum! My friend Beta Pictoris, first star to have its debris disk imaged and including STIS data I worked on as an undergrad, eleven programs in all. It has two planetary companions more massive than #Jupiter #astrosci #exoplanets 🔭
All week I'm going to post some cool spectra from the new Hubble Spectroscopic Archive! First up, PDS 70, a star that hosts a protoplanetary disk and at least one planetary companion in a disk gap! #exoplanets #astrosci 🔭
November 18, 2025 at 3:19 PM
All week I'm going to post some cool spectra from the new Hubble Spectroscopic Archive! First up, PDS 70, a star that hosts a protoplanetary disk and at least one planetary companion in a disk gap! #exoplanets #astrosci 🔭
My team at STScI created an automated system to identify unique astrophysical pointings with #Hubble, classifying the target and creating science ready spectra from all available spectra. Here's an example co-added spectrum from a WD standard observed many times #astrosci 🔭 (3/n)
November 17, 2025 at 7:17 PM
COS and STIS, two of the UV capable spectrographs on #Hubble, have now been operating for 16 and 28 years respectively. They have taken tens of thousands of individual spectra for thousands of targets. We wanted to make it easy for astronomers to make use of that information #astrosci 🔭 (2/)
November 17, 2025 at 7:17 PM
Hey #astrosci community! After working on this project for 3 years, there's a new Hubble Spectroscopic Legacy Archive that's just been newly made available at @stsci.edu: archive.stsci.edu/missions-and... follow me to learn more! (1/n)
November 17, 2025 at 7:17 PM
Hey #astrosci community! After working on this project for 3 years, there's a new Hubble Spectroscopic Legacy Archive that's just been newly made available at @stsci.edu: archive.stsci.edu/missions-and... follow me to learn more! (1/n)
We then compiled all high quality public photometry on it and constructed a crude spectrum to look for excess IR emission from dust or a planet. We added recent SPHEREx data too! If there were any unresolved planets they are <7.5 Mjup. Stay tuned for more! #astrosci 🔭
November 7, 2025 at 5:25 PM
We then compiled all high quality public photometry on it and constructed a crude spectrum to look for excess IR emission from dust or a planet. We added recent SPHEREx data too! If there were any unresolved planets they are <7.5 Mjup. Stay tuned for more! #astrosci 🔭
A little sneak peak from the MEAD survey of white dwarfs within 25 pc using MIRI 10 and 15 micron imaging filters. Visit 101 of the survey captured images of EGGR 199, which is just 16pc away. No planets down to 3 Mjup found nearby the white dwarf! (1/2) #astrosci 🔭
November 7, 2025 at 5:25 PM
A little sneak peak from the MEAD survey of white dwarfs within 25 pc using MIRI 10 and 15 micron imaging filters. Visit 101 of the survey captured images of EGGR 199, which is just 16pc away. No planets down to 3 Mjup found nearby the white dwarf! (1/2) #astrosci 🔭
A little over 23 years ago, I wrote my first paper on white dwarf planetary systems and not only am I fortunate enough to still be able to go looking for them with JWST, that little paper (which almost got rejected) hit 400 citations #astrosci #exoplanets
November 4, 2025 at 7:48 PM
A little over 23 years ago, I wrote my first paper on white dwarf planetary systems and not only am I fortunate enough to still be able to go looking for them with JWST, that little paper (which almost got rejected) hit 400 citations #astrosci #exoplanets
Sometimes being an astronomer is hard. In those moments I’ll reach into my desk for something that cheers me up. After I find that thing I also will look at my vintage @alyankovic.bsky.social tape
October 29, 2025 at 12:38 PM
Sometimes being an astronomer is hard. In those moments I’ll reach into my desk for something that cheers me up. After I find that thing I also will look at my vintage @alyankovic.bsky.social tape
Who robbed the Louvre? Right answers only
October 19, 2025 at 6:09 PM
Who robbed the Louvre? Right answers only
Current status: tired 😴
October 13, 2025 at 1:51 AM
Current status: tired 😴
Not as pretty, but I caught them too!
August 18, 2025 at 10:05 AM
Not as pretty, but I caught them too!
This is very preliminary work, but it suggests that Roman in space is likely going to be much more stable than Hubble's current visible coronagraph on STIS. Even when you're not running at full bore, you should be able to achieve a lot of science. (original figure from Vanessa Bailey) #astrosci
August 6, 2025 at 12:36 PM
This is very preliminary work, but it suggests that Roman in space is likely going to be much more stable than Hubble's current visible coronagraph on STIS. Even when you're not running at full bore, you should be able to achieve a lot of science. (original figure from Vanessa Bailey) #astrosci
Thanks to top notch simulation work from Jessica Gersch-Range, using the OS11 simulation framework, we looked at CGI performance with a flat-DM, i.e. no active correction of the wavefront evolution. I then performed a simple ADI reduction and got down to ~10^-8 contrast (!!)
August 6, 2025 at 12:36 PM
Thanks to top notch simulation work from Jessica Gersch-Range, using the OS11 simulation framework, we looked at CGI performance with a flat-DM, i.e. no active correction of the wavefront evolution. I then performed a simple ADI reduction and got down to ~10^-8 contrast (!!)
Sax says, “Come hither and pet my belly for a sharp surprise!”
August 1, 2025 at 12:13 PM
Sax says, “Come hither and pet my belly for a sharp surprise!”
Hey #HWO2025, just a five minute walk from the conference is Oyamel, a fantastic Mexican restaurant. The ceviche and guacamole is yum and I dare you to try a cricket or cactus taco!
July 30, 2025 at 12:18 AM
Hey #HWO2025, just a five minute walk from the conference is Oyamel, a fantastic Mexican restaurant. The ceviche and guacamole is yum and I dare you to try a cricket or cactus taco!
@bmacastro.bsky.social talking now about NASA's new flagship, about to launch, the Nancy Grace Roman telescope (@nancyromansci.bsky.social) which has a coronagraph on it. It's a good observatory to find giant planets and maybe dust in the habitable zone #HWO2025 #exoplanets
July 28, 2025 at 1:36 PM
@bmacastro.bsky.social talking now about NASA's new flagship, about to launch, the Nancy Grace Roman telescope (@nancyromansci.bsky.social) which has a coronagraph on it. It's a good observatory to find giant planets and maybe dust in the habitable zone #HWO2025 #exoplanets
This year a robin couple raised 4 chicks by our porchlight and then a wren family repurposed the nest. It’s been a baby birb summer 🤩
July 27, 2025 at 1:51 PM
This year a robin couple raised 4 chicks by our porchlight and then a wren family repurposed the nest. It’s been a baby birb summer 🤩
Scribbles and Luna showing off their toe beans!
July 11, 2025 at 2:59 PM
Scribbles and Luna showing off their toe beans!
We found 2 candidates out of 4 objects suggesting that planets may be extremely common around white dwarfs with metals. Within 25pc (or 80 ly), about 20% of WDs have metals, meaning at least half of them will have planets that #JWST can find! #exoplanets #astrosci credit: NASA/JPL/GSFC (10/n)
June 27, 2025 at 2:41 PM
We found 2 candidates out of 4 objects suggesting that planets may be extremely common around white dwarfs with metals. Within 25pc (or 80 ly), about 20% of WDs have metals, meaning at least half of them will have planets that #JWST can find! #exoplanets #astrosci credit: NASA/JPL/GSFC (10/n)
We think these are planets w/ Teff~250 K or less, dominated by water clouds, just like Jupiter. Because they are mixed with the WD's light, they have to be <10au from their host star, around where we think Jupiter would end up after our Sun goes *poof* Credit: NASA (9/n)
June 27, 2025 at 2:41 PM
We think these are planets w/ Teff~250 K or less, dominated by water clouds, just like Jupiter. Because they are mixed with the WD's light, they have to be <10au from their host star, around where we think Jupiter would end up after our Sun goes *poof* Credit: NASA (9/n)
The yellow squares = planet fluxes, while the red, blue, and pink lines are three types of disks. The red line is a very faint warm disk. The blue line comes from a disk at 0.05 au. The pink line would be a very massive version of our asteroid belt. #astrosci #exoplanets (7/n)
June 27, 2025 at 2:41 PM
The yellow squares = planet fluxes, while the red, blue, and pink lines are three types of disks. The red line is a very faint warm disk. The blue line comes from a disk at 0.05 au. The pink line would be a very massive version of our asteroid belt. #astrosci #exoplanets (7/n)
If it's dust, it would be very cold and different from the dust we have previously observed. Also hard to explain. But with just one excess point, we can't rule it out. See this great modeling work by Smith undergrad (and future JHU grad student) Ash Messier #astrosci #exoplanets (6/n)
June 27, 2025 at 2:41 PM
If it's dust, it would be very cold and different from the dust we have previously observed. Also hard to explain. But with just one excess point, we can't rule it out. See this great modeling work by Smith undergrad (and future JHU grad student) Ash Messier #astrosci #exoplanets (6/n)