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Incriminating information:


I am a faculty member in the Astrophysics group at University College London, and a 2012 Ernest Rutherford Fellow.  Prior to UCL, I was a Senior Fellow at the Institute of Astronomy in Cambridge, and held postdoctorial positions at the University of Leicester and Gemini Observatory North.  My doctoral research was carried out at the University of California, Los Angeles.


My main research activity is digging up evidence of terrestrial planetary systems at stellar corpses known as white dwarfs. One might not expect to find the surviving planetary systems around dead stars, but the universe is full of surprises. In fact, it is likely we will learn more about extrasolar terrestrial planets using white dwarfs than via any other method. This is because cool white dwarfs have pure hydrogen and helium atmospheres, and those stars with rocky planetary systems can become polluted by small yet detectable amounts of heavy elements, such as metals. We can use this metal pollution to measure the composition of the rocky planetary material, and even identify water.


I use the Hubble and the Spitzer Space Telescopes to analyze the rocky debris around white dwarfs; the current picture is that they externally polluted with heavy elements from tidally destroyed asteroids.  The parent bodies descend from large and differentiated objects, and these may be leftover planetary building blocks or fragments of major planets.  The compositions measured to date are similar to the material found in the inner Solar System (i.e. like Earth!). Currently, we estimate that at least 20-30% of all white dwarfs harbor terrestrial planetary system remnants. Relevant publications and press releases can be found below.




Fond memories:


As a graduate student, I worked with Eric Becklin & Ben Zuckerman searching for low mass stellar and substellar companions to nearby white dwarfs. The bulk of my thesis is published in an ApJ Supplement Series paper. If you want all the gory details (they are both plentiful and colorful), you can find my thesis here:


The central result of my thesis: a spectral type histogram of low mass companions to white dwarfs. The drop off in companion frequency is clearly above the minimum mass for hydrogen burning, which corresponds to an early L dwarf spectral type / temperature at typical white dwarf ages of one to a few Gyr. Our sensitivity is off the chart. As with solar-type main sequence stars, intermediate mass stars (the progenitors of white dwarfs) with brown dwarf companions are rare.  




Passions, obsessions, lust for knowledge:


The assembly and fate of planetary systems


Origin and evolution of low mass objects


The local cool white dwarf population


Digging in the stellar graveyard



I am fortunate to have several space-based research programs.  Many are posted below with more on the way...




Opinions backed by evidence:



58) A Circumbinary Debris Disk in a Polluted White Dwarf System: astro-ph | Nature Astronomy | press


57) Solar Abundances of Rock Forming Elements, Extreme Oxygen and Hydrogen in a Young Polluted White Dwarf: astro-ph | MNRAS


56) Carbon to Oxygen Ratios in Extrasolar Planetesimals: astro-ph | MNRAS


55) Circumstellar Debris and Pollution at White Dwarf Stars: astro-ph | NewAR | press


54) High-Speed Photometry of the Disintegrating Planetesimals at WD 1145+017: Evidence for Rapid Dynamical Evolution: astro-ph | ApJ


53) Likely Detection of Water-Rich Asteroid Debris in a Metal-Polluted White Dwarf: astro-ph | MNRAS | press


52) The Frequency and Infrared Brightness of Circumstellar Discs at White Dwarfs: astro-ph | MNRAS


51) Signs of a Faint Disc Population at Polluted White Dwarfs: astro-ph | MNRAS


50) ALMA and Herschel Observations of the Prototype Dusty and Polluted White Dwarf G29-38: astro-ph | MNRAS


49) Heavy Metals in a Light White Dwarf: Abundances of the Metal-Rich, Extremely Low-Mass GALEX J1717+6757: astro-ph | MNRAS


48) The Puzzling Source IGR J17361-4441 in NGC 6388: A Possible Planetary Tidal Disruption Event: astro-ph | MNRAS


47) The Frequency of Planetary Debris at Young White Dwarfs: astro-ph | A&A


46) Stochastic Accretion of Planetesimals onto White Dwarfs. Constraints on the Mass Distribution of Accreted Material from Atmospheric Pollution: astro-ph | MNRAS


45) Evidence for Water in the Rocky Debris of a Disrupted Extrasolar Minor Planet: astro-ph | Science | press | BBC | Hubble | Nature


44) Evidence of Rocky Planetesimals Orbiting Two Hyades Stars: astro-ph | MNRAS | press | BBC


43) Orbital and Evolutionary Constraints on the Planet Hosting Binary GJ 86 from the Hubble Space Telescope: astro-ph | MNRAS


42) The WIRED Survey III: An Infrared Excess around the Eclipsing Post-Common Envelope Binary SDSS J030308.35+005443.7: astro-ph | ApJ


41) Precision Astrometry of the Exoplanet Host Candidate GD 66: astro-ph | MNRAS


40) The Chemical Diversity of Exoterrestrial Planetary Debris Around White Dwarfs: astro-ph | MNRAS | press


39) Scars of Intense Accretion Episodes at Metal-Rich White Dwarfs: astro-ph | MNRAS


38) Gaseous Material Orbiting the Polluted White Dwarf HE 1349-2305: astro-ph | ApJ


37) The Origin of Circumstellar Features in the Spectra of Hot DA White Dwarfs: astro-ph | MNRAS


36) Constraints on the Lifetimes of Disks Resulting from Tidally Destroyed Rocky Planetary Bodies: astro-ph | ApJ


35) A Trio of Metal-Rich Dust and Gas Disks Found Orbiting Candidate White Dwarfs with K-Band Excess: astro-ph | MNRAS


34) An Extremely Luminous Panchromatic Outburst from the Nucleus of a Distant Galaxy: astro-ph | Science | BBC


33) Evolutionary Constraints on the Planet-Hosting Subgiant epsilon Reticulum from its White Dwarf Companion: astro-ph | MNRAS


32) Accretion of a Terrestrial-Like Minor Planet by a White Dwarf: astro-ph | ApJ


31) The Magnetic and Metallic Degenerate G77-50: astro-ph | MNRAS


30) Possible Signs of Water and Differentiation in a Rocky Exoplanetary Body: astro-ph | ApJL


29) White Dwarf - Red Dwarf Systems Resolved with the Hubble Space Telescope. II. Full Snapshot Survey Results: astro-ph | ApJS


28) A Detailed Model Atmosphere Analysis of Cool White Dwarfs in the Sloan Digital Sky Survey: astro-ph | ApJS


27) Strengthening the Case for Asteroidal Accretion: Evidence for Subtle and Diverse Disks at White Dwarfs: astro-ph | ApJ


26) Does GD 356 Have a Terrestrial Planetary Companion?: astro-ph | MNRAS


25) Rocky Planetesimals as the Origin of Metals in DZ Stars: astro-ph | MNRAS | press


24) IRTF Observations of White Dwarfs with Possible Near-Infrared Excess: astro-ph | MNRAS


23) Deep Imaging Survey of Young, Nearby Austral Stars. VLT / NACO Near-infrared Lyot-Coronographic Observations: astro-ph | A&A


22) A Glimpse of the End of the Dark Ages: The Gamma-Ray Burst of 23 April 2009 at Redshift 8.3: astro-ph | Nature | BBC


21) X-Ray and Infrared Observations of Two Externally-Polluted White Dwarfs: astro-ph | ApJ | press


20) PHL 5038: A Spatially Resolved White Dwarf - Brown Dwarf Binary: astro-ph | A&A


19) Infrared Signatures of Disrupted Minor Planets at White Dwarfs: astro-ph | ApJ | press | BBC


18) Six White Dwarfs with Circumstellar Silicates: astro-ph | AJ | press


17) Spitzer IRAC Observations of White Dwarfs. II. Massive Planetary and Cold Brown Dwarf Companions to Young and Old Degenerates: astro-ph | ApJ


16) Near-Infrared Constraints on the Presence of Warm Dust at Metal-Rich Helium Atmosphere White Dwarfs: astro-ph | AJ


15) Spitzer IRAC Observations of White Dwarfs. I. Warm Dust at Metal-Rich Degenerates: astro-ph | ApJ


14) A Near-Infrared Spectroscopic Study of the Accreting Magnetic White Dwarf SDSS J121209.31+013627.7 and Its Substellar Companion: astro-ph | ApJ | press


13) Externally Polluted White Dwarfs with Dust Disks: astro-ph | ApJ


12) Infrared Emission from the Dusty Disk Orbiting GD 362, an Externally Polluted White Dwarf: astro-ph | AJ | press


11) The Nature of the Close Magnetic White Dwarf - Probable Brown Dwarf Binary SDSSJ121209.31+013627.7: astro-ph | MNRAS


10) HST NICMOS Imaging of the Planetary-mass Companion to the Young Brown Dwarf 2MASSW J1207334-393254: astro-ph | ApJ | press


9) White Dwarf - Red Dwarf Systems Resolved with the Hubble Space Telescope. I. First Results: astro-ph | ApJ


8) Low-Luminosity Companions to White Dwarfs (thesis work): astro-ph | ApJS


7) Mid-Infrared Observations of the White Dwarf - Brown Dwarf Binary GD 1400: astro-ph | AJ


6) A Dusty Disk around GD 362, a White Dwarf with a Uniquely High Photospheric Metal Abundance: astro-ph | ApJL | press


5) SSSPM J1549-3544 Is Not a White Dwarf: astro-ph | ApJL


4) Cool versus Ultracool White Dwarfs: astro-ph | AJ


3) A Possible Brown Dwarf Companion to the White Dwarf GD 1400: astro-ph | AJ


2) Discovery of an Ultracool White Dwarf Companion: astro-ph | ApJ


1) Mid-Infrared Observations of van Maanen 2: No Substellar Companion: astro-ph | ApJL




Meme exchange:


Jay Farihi


Ernest Rutherford Fellow


Lecturer / Assistant Professor


Physics and Astronomy


University College London


London WC1E 6BT


United Kingdom



Phone: +44 203 549 5812



j dot farihi at ucl dot ac dot uk