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Publication list

 Refereed journal articles and refereed review articles (citations/non-self in brackets):
  1. The role of pebble fragmentation in planetesimal formation II. Numerical simulations (2017)
    Wahlberg Jansson K., Johansen A., Bukhari Syed M., & Blum J.
    The Astrophysical Journal, vol. 835, id. 109 (11 p.)
    [arXiv:1609.07052] [1/1]

  2. The role of pebble fragmentation in planetesimal formation I. Experimental study (2017)
    Bukhari Syed M., Blum J., Wahlberg Jansson K., & Johansen A.
    The Astrophysical Journal, vol. 834, id. 145 (34 p.)
    [arXiv:1609.06914] [1/0]

  3. Initial mass function of planetesimals formed by the streaming instability (2017)
    Schäfer U., Yang C.-C., & Johansen A.
    Astronomy & Astrophysics, vol. 597, id. A69 (10 p.)
    [arXiv:1611.02285] [3/2]

  4. Dust Evolution and the Formation of Planetesimals (2016)
    Birnstiel T., Fang M., & Johansen A.
    Space Science Reviews, vol. 205, p. 41-75
    [arXiv:1604.02952] [6/6]

  5. Survival of habitable planets in unstable planetary systems (2016)
    Carrera D., Davies M. B., & Johansen A.
    Monthly Notices of the Royal Astronomical Society, vol. 463 p. 3226-3238
    [arXiv:1605.01325] [2/1]

  6. Terrestrial Planets across Space and Time (2016)
    Zackrisson E., Calissendorff P., González J., Benson A., Johansen A., & Janson M.
    The Astrophysical Journal, vol. 833, id. 214 (12 p.)
    [arXiv:1602.00690] [3/3]

  7. Forming Chondrules in Impact Splashes II Volatile Retention (2016)
    Dullemond C. P., Harsono D., Stammler S. M., & Johansen A.
    The Astrophysical Journal, vol. 832, id. 91 (19 p.) [0/0]

  8. Long-term stability of the HR 8799 planetary system without resonant lock (2016)
    Götberg Y., Davies M. B., Mustill A. J., Johansen A., & Church R. P.
    Astronomy & Astrophysics, vol. 592, id. A147 (14 p.)
    [arXiv:1606.07819] [3/2]

  9. Integration of Particle-gas Systems with Stiff Mutual Drag Interaction (2016)
    Yang C.-C, & Johansen A.
    The Astrophysical Journal Supplement Series, vol. 224, id. 39 (20 p.)
    [arXiv:1603.08523] [3/2]

  10. Spontaneous concentrations of solids through two-way gas drag on sedimenting particles (2016)
    Lambrechts M., Johansen A., Capelo H., Blum J., & Bodenschatz E.
    Astronomy & Astrophysics, vol. 591, id. A133 (14 p.)
    [arXiv:1604.00791] [2/2]

  11. Influence of the water content in protoplanetary discs on planet migration and formation (2016)
    Bitsch B., & Johansen A.
    Astronomy & Astrophysics, vol. 590, id. A101 (15 p.)
    [arXiv:1603.01125] [1/1]

  12. Fossilized condensation lines in the Solar System protoplanetary disk (2016)
    Morbidelli A., Bitsch B., Crida A., Gounelle M., Guillot T., Jacobson S., Johansen A., Lambrechts M., & Lega E.
    Icarus, vol. 267, p. 368-376
    [arXiv:1511.06556] [14/13]

  13. The growth of planets by pebble accretion in evolving protoplanetary discs (2015)
    Bitsch B., Lambrechts M., & Johansen A.
    Astronomy & Astrophysics, vol. 582, id. A112 (24 p.)
    [arXiv:1507.05209] [36/32]

  14. The destruction of inner planetary systems during high-eccentricity migration of gas giants (2015)
    Mustill A., Davies M. B., & Johansen A.
    The Astrophysical Journal, vol. 808, id. 14 (11 p.)
    [arXiv:1502.06971] [17/15]

  15. How to form asteroids from mm-sized chondrules and chondrule aggregates (2015)
    Carrera D., Johansen A., & Davies M.
    Astronomy & Astrophysics, vol. 579, id. A43 (20 p.)
    [arXiv:1501.05314] [43/35]

  16. New paradigms for asteroid formation (2015)
    Johansen A., Jacquet E., Cuzzi J. N., Morbidelli A., & Gounelle M.
    In ASTEROIDS IV, University of Arizona Press (23 p.)
    [arXiv:1505.02941] [4/4]

  17. The formation of the solar system (2015)
    Pfalzner S., Davies M. B., Gounelle M., Johansen A., Münker C., Lacerda P., Portegies Zwart S., Testi L., Trieloff M., & Veras D.
    Physica Scripta, vol. 90, id. 068001 (18 p.)
    [arXiv:1501.03101] [9/9]

  18. Growth of asteroids, planetary embryos and Kuiper belt objects by chondrule accretion (2015)
    Johansen A., Mac Low M.-M., Lacerda P., & Bizzarro M.
    Science Advances, vol. 1, id. e1500109 (11 p.)
    [arXiv:1503.07347] [54/43]

  19. The structure of protoplanetary discs around evolving young stars (2015)
    Bitsch B., Johansen A., Lambrechts M., & Morbidelli M.
    Astronomy & Astrophysics, vol. 575, id. A28 (17 p.)
    [arXiv:1411.3255] [47/39]

  20. Forming chondrules in impact splashes I. Radiative cooling model (2014)
    Dullemond C. P., Stammler S. M., & Johansen A.
    The Astrophysical Journal, vol. 794, id. 91 (12 p.)
    [7/7]

  21. Forming the cores of giant planets from the radial pebble flux in protoplanetary discs (2014)
    Lambrechts M., & Johansen A.
    Astronomy & Astrophysics, vol. 572, id. A107 (12 p.)
    [arXiv:1408.6094] [58/48]

  22. Separating gas-giant and ice-giant planets by halting pebble accretion (2014)
    Lambrechts M., Johansen A., & Morbidelli A.
    Astronomy & Astrophysics, vol. 572, id. A35 (12 p.)
    [arXiv:1408.6087] [38/32]

  23. Formation of pebble-pile planetesimals (2014)
    Wahlberg Jansson K., & Johansen A.
    Astronomy & Astrophysics, vol. 570, id. A47 (10 p.)
    [arXiv:1408.2535] [21/19]

  24. On the feeding zone of planetesimal formation by the streaming instability (2014)
    Yang C.-C., & Johansen A.
    The Astrophysical Journal, vol. 792, id. 86 (10 p.)
    [arXiv:1407.5995] [12/5]

  25. The PLATO 2.0 mission (2014)
    Rauer H., & et al. (including Johansen A.)
    Experimental Astronomy, vol. 38, p. 249-330
    [arXiv:1310.0696] [259/258]

  26. A fossil winonaite-like meteorite in Ordovician limestone: A piece of the impactor that broke up the L-chondrite parent body? (2014)
    Schmitz B., Huss G. R., Meier M. M. M., et al. (including Johansen A.)
    Earth and Planetary Science Letters, vol. 400, p. 145-152
    [7/7]

  27. The multifaceted planetesimal formation process (2014)
    Johansen A., Blum J., Tanaka H., Ormel C., Bizzarro M., & Rickman H.
    In Protostars and Planets VI, University of Arizona Press (24 p.)
    [arXiv:1402.1344] [73/62]

  28. Giant planet and brown dwarf formation (2014)
    Chabrier G., Johansen A., Janson M., & Rafikov R.
    In Protostars and Planets VI, University of Arizona Press (23 p.)
    [arXiv:1401.7559] [43/43]

  29. Ice condensation as a planet formation mechanism (2013)
    Ros K., & Johansen A.
    Astronomy & Astrophysics, vol. 552, id. A137 (14 p.)
    [arXiv:1302.3755] [78/66]

  30. Gravoturbulent planetesimal formation: the positive effect of long-lived zonal flows (2013)
    Dittrich K., Klahr H., & Johansen A.
    The Astrophysical Journal, vol. 763, id. 117 (17 p.)
    [arXiv:1211.2095] [37/34]

  31. Magnetically-levitating accretion disks around supermassive black holes (2012)
    Gaburov E., Johansen A., & Levin Y.
    The Astrophysical Journal, vol. 758, id. 103 (11 p.)
    [arXiv:1201.4873] [19/19]

  32. Can planetary instability explain the Kepler dichotomy? (2012)
    Johansen A., Davies M. B., Church R. P., & Holmelin V.
    The Astrophysical Journal, vol. 758, id. 39 (15 p.)
    [arXiv:1206.6898] [42/36]

  33. Rapid growth of gas-giant cores by pebble accretion (2012)
    Lambrechts M., & Johansen A.
    Astronomy & Astrophysics, vol. 544, id. A32 (13 p.)
    [arXiv:1205.3030] [161/147]

  34. An abundance of small exoplanets around stars with a wide range of metallicities (2012)
    Buchhave L., Latham D. W., Johansen A., Bizzarro M., Torres G., Rowe J. F., et al.
    Nature, vol. 486, p. 375-377
    [256/252]

  35. Adding particle collisions to the formation of asteroids and Kuiper belt objects via streaming instabilities (2012)
    Johansen A., Youdin A., & Lithwick Y.
    Astronomy & Astrophysics, vol. 537, id. A125 (17 p.)
    [arXiv:1111.0221] [53/40]

  36. High-resolution simulations of planetesimal formation in turbulent protoplanetary discs (2011)
    Johansen A., Klahr H., & Henning Th.
    Astronomy & Astrophysics, vol. 529, id. A62 (16 p.)
    [arXiv:1010.4757] [51/41]

  37. Prograde rotation of protoplanets by accretion of pebbles in a gaseous environment (2010)
    Johansen A., & Lacerda P.
    Monthly Notices of the Royal Astronomical Society, vol. 404, p. 475-485
    [arXiv:0910.1524] [61/50]

  38. Particle clumping and planetesimal formation depend strongly on metallicity (2009)
    Johansen A., Youdin A., & Mac Low M.-M.
    The Astrophysical Journal, vol. 704, p. L75-L79
    [arXiv:0909.0259] [133/112]

  39. Zonal flows and long-lived axisymmetric pressure bumps in magnetorotational turbulence (2009)
    Johansen A., Youdin A., & Klahr H.
    The Astrophysical Journal, vol. 697, p. 1269-1289
    [arXiv:0811.3937] [138/123]

  40. Planet formation bursts in the edges of the dead zone (2009)
    Lyra W., Johansen A., Zsom A., Klahr H., & Piskunov N.
    Astronomy & Astrophysics, vol. 497, p. 869-888
    [arXiv:0901.1638] [96/95]

  41. Standing on the shoulders of giants. Trojan Earths and vortex trapping in low mass self-gravitating protoplanetary disks of gas and solids (2009)
    Lyra W., Johansen A., Klahr H., & Piskunov N.
    Astronomy & Astrophysics, vol. 493, p. 1125-1139 [A&A cover]
    [arXiv:0810.3192] [68/64]

  42. Embryos grown in the dead zone. Assembling the first protoplanetary cores in low mass self-gravitating circumstellar disks of gas and solids (2008)
    Lyra W., Johansen A., Klahr H., & Piskunov N.
    Astronomy & Astrophysics, vol. 491, p. L41-L44
    [arXiv:0807.2622] [58/50]

  43. High accretion rates in magnetised Keplerian discs mediated by a Parker instability driven dynamo (2008)
    Johansen A., & Levin Y.
    Astronomy & Astrophysics, vol. 490, p. 501-514
    [arXiv:0808.3579] [36/35]

  44. A coagulation-fragmentation model for the turbulent growth and destruction of preplanetesimals (2008)
    Johansen A., Brauer F., Dullemond C.P., Klahr H., & Henning Th.
    Astronomy & Astrophysics, vol. 486, p. 597-611
    [arXiv:0802.3331] [33/24]

  45. Global models of turbulence in protoplanetary disks I. A cylindrical potential on a Cartesian grid and transport of solids (2008)
    Lyra W., Johansen A., Klahr H., & Piskunov N.
    Astronomy & Astrophysics, vol. 479, p. 883-901
    [arXiv:0705.4090] [52/41]

  46. Rapid planetesimal formation in turbulent circumstellar discs (2007)
    Johansen A., Oishi J., Mac Low M.-M., Klahr H., Henning Th., & Youdin A.
    Nature, vol. 448, p. 1022-1025
    [arXiv:0708.3890, arXiv:0708.3893] [508/477]

  47. Survival of the mm-cm size grain population observed in protoplanetary discs (2007)
    Brauer F., Dullemond C. P., Johansen A., Henning Th., Klahr H., & Natta A.
    Astronomy & Astrophysics, vol. 469, p. 1169-1182
    [arXiv:0704.2332] [64/56]

  48. Protoplanetary disc turbulence driven by the streaming instability: Non-linear saturation and particle concentration (2007)
    Johansen A., & Youdin A.
    The Astrophysical Journal, vol. 662, p. 627-641
    [astro-ph/0702626] [128/102]

  49. Protoplanetary disc turbulence driven by the streaming instability: Linear evolution and numerical methods (2007)
    Youdin A., & Johansen A.
    The Astrophysical Journal, vol. 662, p. 613-626
    [astro-ph/0702625] [98/76]

  50. Turbulent diffusion in protoplanetary discs: The effect of an imposed magnetic field (2006)
    Johansen A., Klahr H., & Mee A. J.
    Monthly Notices of the Royal Astronomical Society, vol. 370, p. L71-L75
    [astro-ph/0603765] [43/40]

  51. Dust sedimentation and self-sustained Kelvin-Helmholtz turbulence in protoplanetary disc mid-planes (2006)
    Johansen A., Henning Th., & Klahr H.
    The Astrophysical Journal, vol. 643, p. 1219-1232
    [astro-ph/0512272] [74/65]

  52. Gravoturbulent formation of planetesimals (2006)
    Johansen A., Klahr H., & Henning Th.
    The Astrophysical Journal, vol. 636, p. 1121-1134
    [astro-ph/0504628] [88/73]

  53. Dust diffusion in protoplanetary discs by magnetorotational turbulence (2005)
    Johansen A., & Klahr H.
    The Astrophysical Journal, vol. 634, p. 1353-1371
    [astro-ph/0501641] [101/86]

  54. Simulations of dust-trapping vortices in protoplanetary discs (2004)
    Johansen A., Andersen A. C., & Brandenburg A.
    Astronomy & Astrophysics, vol. 417, p. 361-374 [A&A cover]
    [astro-ph/0310059] [89/80]

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Press coverage

Movies

Asteroid formation at high resolution
The movie shows a high-resolution computer simulation of asteroid formation by the streaming instability. The metallicity starts at Z=0.01. Particles of 10 cm in size sediment to form a thin mid-plane layer, but the mid-plane layer gradually puffs up due to turbulent stirring. The movie makes a jump from a time of 50 to a time of 200 when the metallicity is slowly increased to Z=0.02. This triggers the formation of dense filaments at a time of around 250. After the dispersal of the second filament the particle self-gravity is activated. The next filament collapses gravitationally to asteroids with a wide range of sizes. Their Hill radii are indicated on the top right panel and their radii on the bottom right panel.
File size: 19.1 MB
References: Johansen et al. (2015)
Long time-span simulation of planetesimal formation
Previous simulations of particle clumping in protoplanetary disc turbulence have only been able to follow planetesimal formation for a few orbital periods. With a computing grant for 4096 core years at the Jugene supercomputer in Jülich we recently were able to run high-resolution simulations (5123) and long time-span simulations (at 2563) of magnetorotational turbulence with particles. The movie shows a simulation where self-gravity was started at the same time as releasing the particles. In this cold start initial condition planetesimals form slowly over the next 13 orbits. The circles indicate the Hill spheres of the bound clumps and the number their mass in units of the 1000-km-diameter dwarf planet Ceres.
File size: 41.9 MB
References: Johansen, Klahr, & Henning (2011)
Prograde rotation of asteroids and protoplanets
The predominantly prograde rotation of terrestrial planets and large asteroids is difficult to explain through the classical picture of planet formation, since run-away accretion of planetesimals leads to slow, retrograde rotation. The tendency for prograde rotation of large asteroids is often attributed to giant impacts and pure chance. However, if asteroids grow primarily by accreting small pebbles embedded in the protoplanetary gas disc, rather than km-sized planetesimals, then prograde rotation is natural. Pebbles approaching the Hill sphere of a protoplanet lose energy by friction with the gas, fall towards the protoplanet, acquire prograde spin from the Coriolis forces and enter a prograde particle disc. The protoplanet obtains prograde angular momentum from particles accreted through the circumplanetary disc.
File size: 15.1 MB
References: Johansen, & Lacerda (2010)

Metallicity controls planetesimal formation
Exoplanets are found primarily around stars that are rich in heavy elements. This is normally attributed to the efficiency of forming several Earth mass cores in short enough time to attract gaseous envelopes and become gas giants. However, already the earlier stages of planet formation, where dust particles grow to km-sized planetesimals, are affected by the metallicity of the disc. Particle clumps that form spontaneously in turbulent flows can become gravitationally unstable and contract to form planetesimals. This clumping, in turn, is highly dependent on the metallicity. The first movie shows a simulation of particle sedimentation, starting at a metallicity equal to that of the sun. The gas is removed on a 30 orbits time-scale. Color contours show particle density, with bright regions containing many particles and blue regions few. Initially there is almost no clumping in the particle component, but as the metallicity is increased, strong clumping sets in. The second movie shows the formation of planetesimals in a simulation with two times the solar heavy element abundance. Seven gravitationally bound clusters, containing pebbles of a few cms in radius, condense out of the overdense filament.
File size: 67.1 MB, 9.2 MB
References: Johansen, Youdin, & Mac Low (2009)

The Parker instability in a strongly magnetised accretion disc
Strongly magnetised accretion discs are unstable to the Parker instability. The movie shows the vertical field strength at the sides of the simulation box. Typical Parker instability modes of short radial wavelength and long (about five scale heights) azimuthal wavelength are visible. As the initial azimuthal field rises in big arcs, vertical field is created, which in turn becomes unstable to the magnetorotational instability. The mid-plane also shows signs of magnetorotational instability in the azimuthal field. The turbulent state has high accretion torques, with an alpha-value of around 0.1. A large scale radial field appears due to the stretching of field lines as matter streams down the inclined field lines. The radial field component in turn re-creates the azimuthal field by stretching in the Keplerian shear. This way the azimuthal field stays confined to the disc, and the high accretion rate can be maintained.
File size: 18.9 MB
References: Johansen & Levin (2008)

Formation of gravitationally bound clusters of boulders
The movie shows the column density of boulders in a protoplanetary disc. Initially the particles have been allowed to evolve without feeling each other's gravity, but at the onset of the movie self-gravity is turned on. The radial contraction of the boulder component leads eventually to a full non-axisymmetric collapse into a gravitationally bound cluster, containing a mass in solids that is comparable to the dwarf planet Ceres. The inset shows an enlargement around the densest point in the simulation. Clear accretion features are visible as the clump consumes the remaining boulders in the box. A second massive clump condenses out at a time of around 3.5 orbits when the first clump interacts with a dense filament of particles.
File size: 10.0 MB
References: Johansen, Oishi, Mac Low, Klahr, Henning, & Youdin (2007)

The radial drift of solids is unstable to the streaming instability
It is a notorious problem of planet formation that m-sized boulders drift into the central protostar because of the friction with the gas disk. But Youdin & Goodman (2005) showed that the flow of dust and gas is linearly unstable to the streaming instability (confirmed numerically in the simulations by Johansen, Henning, & Klahr 2006). The two movies show how the radial drift flow turns turbulent, creating high density particle clumps. The first movie is from a 3-D simulation where the particles represent m-sized boulders. The flow shows initially the linear growth of the streaming instability, but the wave patterns eventually go non-linear and turbulent on a time-scale that is shorter than the radial drift. The second movie shows a 2-D simulation where the particles represent 10 cm rocks. Here the drift flow is weaker, and the turbulence sets in almost instantaneously through the creation of rapidly expanding voids.
File size: 29.1 MB, 4.8 MB
References: Johansen & Youdin (2007); Youdin & Johansen (2007)

Pebbles, rocks and boulders moving in Kelvin-Helmholtz turbulence
The three movies show particle density contours in a two-dimensional azimuthal-vertical slice of a protoplanetary disc, for three different particle sizes (cm-sized pebbles, dm-sized rocks and m-sized boulders). There is no global turbulence in the disc, so the solid particles sediment unhindered towards the disc mid-plane. Due to a radial pressure gradient through the disc, the gas rotates at a speed that is slightly below the Keplerian value. However, as the particles settle around the mid-plane, the gas is forced by the solids to rotate more and more Keplerian, inducing a vertical dependence of the rotation velocity of the gas. This shear flow is unstable to the Kelvin-Helmholtz instability, forming beautiful breaking waves in the dust layer. In the self-sustained state of Kelvin-Helmholtz turbulence the solid particles are transported away from the mid-plane at the same rate as they fall, but the particle density is nevertheless very clumpy because of a clumping instability that is caused by the dependence of the particle rotation velocity on the local solids-to-gas ratio.
File size: 14.3 MB, 18.6 MB, 11.2 MB
References: Johansen, Henning, & Klahr (2006)

Boulders trapped in magnetorotational turbulence
The movie shows the locations of 100,000 of a total of 2,000,000 meter-sized solid particles moving around in magnetorotational turbulence. Large concentrations are seen, up to a factor of 100 in solids-to-gas ratio, due to trapping of boulders in transient high pressures that have a few percent overdensity in the gas. A global gas pressure gradient is causing particles to migrate inwards. This also contributes to the concentrations by loading gas overdensity regions with migrating boulders.
File size: 11.9 MB
References: Johansen, Klahr, & Henning (2006)

Dust settled in magnetorotational turbulence
The movie shows dust density contours at the sides of a simulation box representing a local, corotating coordinate frame in a protoplanetary disc. The radial direction is towards the right, the rotation direction towards left and the vertical direction upwards. The dust is concentrated around the mid-plane due to vertical gravity, but the configuration is now in an equilibrium where the turbulent gas transports dust away from the mid-plane at the same rate as the settling. The scale height of the dust grains allows determination of the diffusion coefficient of the turbulent flow.
File size: 8.7 MB
References: Johansen & Klahr (2005)

This page was last modified on 1 April 2017.