https://www.darrylseligman.com/new-events daily 0.75 2017-09-30 https://www.darrylseligman.com/new-events/2017/9/27/yale-computational-hydrodynamics-meeting-1 monthly 0.5 2024-01-26 https://www.darrylseligman.com/exoplanet-journal-club daily 0.75 2017-09-30 https://www.darrylseligman.com/welcome daily 0.75 2023-07-15 https://images.squarespace-cdn.com/content/v1/5052176b84aeb45fa5cfcc83/1349577199654-C8A6HP2M4MLEBJXQ06MF/wilderness.png Welcome - Transient https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590622725655-WIZ7PAC1K1BJKMHJO18E/headshot_seligman.png Welcome https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590622725655-WIZ7PAC1K1BJKMHJO18E/headshot_seligman.png Welcome https://www.darrylseligman.com/observational-cosmology daily 0.75 2017-07-10 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1499717490576-I2Q4JR7O8GS2L9ZSZI8G/GBT.jpg Observational Cosmology https://www.darrylseligman.com/oumuamua daily 0.75 2019-02-05 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1517166002734-214HFDCB1J7VCJQ0M5JY/interstellar_asteroid.jpg 1I/'Oumuamua https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1549312088537-YCC405E46VU2W9DK2205/schematic_diagramv3.jpg 1I/'Oumuamua Figure 1: Schematic of the Adopted Jet Model https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1549323580085-35IWBC4V878FDCYZ00QW/skymap.jpg 1I/'Oumuamua Figure 2: Skymap https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1517166180191-HHVQMLFUE7WMMQGMM2ST/intercept.jpg 1I/'Oumuamua Figure 3: Minimum Energy Interception Schematic https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1549323920122-MYKKKWDCYKFQBXU1Q40C/lsst.jpg 1I/'Oumuamua Figure 4: Construction of LSST https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1521478519182-SRNPLLUIT9VP1OQYS8G4/missions_years.jpg 1I/'Oumuamua Figure 5: Feasability of Missions to Future ‘Oumuamua like Objects https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1549312088537-YCC405E46VU2W9DK2205/schematic_diagramv3.jpg 1I/'Oumuamua Figure 1: Schematic of the Adopted Jet Model https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1549323580085-35IWBC4V878FDCYZ00QW/skymap.jpg 1I/'Oumuamua Figure 2: Skymap https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1517166180191-HHVQMLFUE7WMMQGMM2ST/intercept.jpg 1I/'Oumuamua Figure 3: Minimum Energy Interception Schematic https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1549323920122-MYKKKWDCYKFQBXU1Q40C/lsst.jpg 1I/'Oumuamua Figure 4: Construction of LSST https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1521478519182-SRNPLLUIT9VP1OQYS8G4/missions_years.jpg 1I/'Oumuamua Figure 5: Feasability of Missions to Future ‘Oumuamua like Objects https://www.darrylseligman.com/rbv2 daily 0.75 2020-05-24 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1532279841352-5YIZKB74TSMC0QH0N5V8/SkewedShearFlow.png RBV2 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590355237521-F6VX46POFRT1JQ7P6TQF/SkewedShearFlowl2norm.jpg RBV2 The fidelity with which RBV2 maintains a skewed shear flow on a square grid. The initial conditions for the simulations are shown in the left panel. The color scale in the image corresponds to the x velocity, u(y). The overlaid arrows give a visual representation of the velocity field. In the right panel, the initial analytic solution is shown in the solid lines, and the numerical solution evolved for 60 sound crossing times is shown in x's. The different colors represent different y cross sections of the grid. The corresponding residuals, (u-u_0)/u_0, are shown in grey stars in the middle panel. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590355336047-VMZSB5HARI20Q8AVKY62/SkewedShearFlow_HigherKl2norm.jpg RBV2 The same skewed shear flow experiment as in Figure 2, with a 4×higher wavenumber. The initial conditions for thesimulations are shown in the left panel. The color scale in the image corresponds to the x-velocity,u(y). The overlaid arrowsgive a visual representation of the velocity field. In the right panel, the initial, analytic solution is shown in the solid lines, and the numerical solution evolved for t∼60 sound crossing times is shown in dots. The purple ×’s show the simulation as the numerical dispersion begins to manifest, and the grey ×’s show the solution as the wave begins to display unsteady behavior. The corresponding residuals, (u−u0)/u0, are shown in grey and purple stars in the middle panel. We initialize the simulation using Equations 18 on a 64×64 zone grid with four times the wavenumber as in Figure 2. The amplitude of the shear flowisA= 0.1, the sound speed is cs= 1 and the domain length is Lx,Ly=√2π. It is evident that the increase in wavenumberincreases the numerical dispersion, as expected https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590355423443-ZXGAESYC2TNWAIDPG0T8/Hydrostatic.jpg RBV2 The evolution of a shear flow in the presence of a vertical hydrostatic equilibrium. The initial conditions for the simulation are shown in the left panel. The color scale in the image corresponds to the normalized density,ρ/ρ0. The overlaid arrows give a visual representation of the magnitude and direction of the gravitational body force balanced by the pressure induced by the density gradient. In the right panel, the initial, analytic solution for the density is shown in the solid line, and the numerical solution evolved to 50 sound crossing times is shown in ×’s. The corresponding residuals, (ρ−ρ0)/ρ0, are shown in grey stars in the middle panel. The simulation was run on a 64×64 zone grid, where Lx=Ly= 1,cs= 1,ρ0= 1, and g=−1. It is evident that with the proposed update, the scheme is able to maintain the hydrostatic equilibrium imposed by the external body forces. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590355488053-53HHW711IAE98VX5094Y/RMS_RHS_Grid.jpg RBV2 A numerical assessment of vorticity preservation for discrete wavenumber, vortical modes up to the Nyquist frequency. We present the RMS of the residual (RHS) of the vorticity equation normalized by the RMS of the original seeded vorticity fora range of vortical modes. The x and y axes correspond to the wavenumbers kx and ky of the seeded vortical mode. The kx,ky= 0 modes correspond to unskewed shear layers, which have been shown analytically to be vorticity preserving https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590355237521-F6VX46POFRT1JQ7P6TQF/SkewedShearFlowl2norm.jpg RBV2 The fidelity with which RBV2 maintains a skewed shear flow on a square grid. The initial conditions for the simulations are shown in the left panel. The color scale in the image corresponds to the x velocity, u(y). The overlaid arrows give a visual representation of the velocity field. In the right panel, the initial analytic solution is shown in the solid lines, and the numerical solution evolved for 60 sound crossing times is shown in x's. The different colors represent different y cross sections of the grid. The corresponding residuals, (u-u_0)/u_0, are shown in grey stars in the middle panel. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590355336047-VMZSB5HARI20Q8AVKY62/SkewedShearFlow_HigherKl2norm.jpg RBV2 The same skewed shear flow experiment as in Figure 2, with a 4×higher wavenumber. The initial conditions for thesimulations are shown in the left panel. The color scale in the image corresponds to the x-velocity,u(y). The overlaid arrowsgive a visual representation of the velocity field. In the right panel, the initial, analytic solution is shown in the solid lines, and the numerical solution evolved for t∼60 sound crossing times is shown in dots. The purple ×’s show the simulation as the numerical dispersion begins to manifest, and the grey ×’s show the solution as the wave begins to display unsteady behavior. The corresponding residuals, (u−u0)/u0, are shown in grey and purple stars in the middle panel. We initialize the simulation using Equations 18 on a 64×64 zone grid with four times the wavenumber as in Figure 2. The amplitude of the shear flowisA= 0.1, the sound speed is cs= 1 and the domain length is Lx,Ly=√2π. It is evident that the increase in wavenumberincreases the numerical dispersion, as expected https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590355423443-ZXGAESYC2TNWAIDPG0T8/Hydrostatic.jpg RBV2 The evolution of a shear flow in the presence of a vertical hydrostatic equilibrium. The initial conditions for the simulation are shown in the left panel. The color scale in the image corresponds to the normalized density,ρ/ρ0. The overlaid arrows give a visual representation of the magnitude and direction of the gravitational body force balanced by the pressure induced by the density gradient. In the right panel, the initial, analytic solution for the density is shown in the solid line, and the numerical solution evolved to 50 sound crossing times is shown in ×’s. The corresponding residuals, (ρ−ρ0)/ρ0, are shown in grey stars in the middle panel. The simulation was run on a 64×64 zone grid, where Lx=Ly= 1,cs= 1,ρ0= 1, and g=−1. It is evident that with the proposed update, the scheme is able to maintain the hydrostatic equilibrium imposed by the external body forces. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590355488053-53HHW711IAE98VX5094Y/RMS_RHS_Grid.jpg RBV2 A numerical assessment of vorticity preservation for discrete wavenumber, vortical modes up to the Nyquist frequency. We present the RMS of the residual (RHS) of the vorticity equation normalized by the RMS of the original seeded vorticity fora range of vortical modes. The x and y axes correspond to the wavenumbers kx and ky of the seeded vortical mode. The kx,ky= 0 modes correspond to unskewed shear layers, which have been shown analytically to be vorticity preserving https://www.darrylseligman.com/magnetic-rdis daily 0.75 2020-05-24 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1532280441757-LPW9O6SPPZS1RPZYA3QN/im_3d2dProj_b_low_hot_0329.png Dust Plasma Instabilities https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1538657586552-2MF50IE74VH1X89QI5XJ/variance_vs_time.png Dust Plasma Instabilities Volume-weighted rms standard deviation of various gas and dust properties vs.\ simulation time. We broadly denote three regimes in time: (i) linear, (ii) early nonlinear, and (iii) saturation. In (i), growth rates are rapid and agree reasonably well with the expectation from linear theory }) for a mix of modes. In (ii) growth continues but at decreasing rates until saturating in (iii). There is strong anisotropy between fluctuations in gas velocity and magnetic field. But for each component, the gas velocity and magnetic field fluctuations are tightly-coupled, especially perpendicular to the magnetic field. Read the relevant papers, Seligman, D., Hopkins, P. F., Squire, J. "Nonlinear Evolution of the Resonant Drag Instability in Magnetized Gas." MNRAS, 485, 3991, 2019 and Hopkins, P. F., Squire, J., Seligman, D. "Simulating the Diverse Instabilities of Dust in Magnetized Gas." MNRAS, 2020. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1538657586552-2MF50IE74VH1X89QI5XJ/variance_vs_time.png Dust Plasma Instabilities Volume-weighted rms standard deviation of various gas and dust properties vs.\ simulation time. We broadly denote three regimes in time: (i) linear, (ii) early nonlinear, and (iii) saturation. In (i), growth rates are rapid and agree reasonably well with the expectation from linear theory }) for a mix of modes. In (ii) growth continues but at decreasing rates until saturating in (iii). There is strong anisotropy between fluctuations in gas velocity and magnetic field. But for each component, the gas velocity and magnetic field fluctuations are tightly-coupled, especially perpendicular to the magnetic field. Read the relevant papers, Seligman, D., Hopkins, P. F., Squire, J. "Nonlinear Evolution of the Resonant Drag Instability in Magnetized Gas." MNRAS, 485, 3991, 2019 and Hopkins, P. F., Squire, J., Seligman, D. "Simulating the Diverse Instabilities of Dust in Magnetized Gas." MNRAS, 2020. https://www.darrylseligman.com/borisov daily 0.75 2020-05-24 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590409365673-874J2YF29UK3XHF96RQS/C2CNRatio.jpg 2I/Borisov https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590356087859-XJZJU4E1J2394T2VXYFU/Productionrates.jpg 2I/Borisov Pre-perihelion production rates of C2 (upper) and CN (lower) in 2I/Borisov in 2019 September–November; its perihelion is 2019 December 8. The left two panels show the measurements and upper limits in Fitzsimmons et al. (2019), Kareta et al. (2019), Opitom et al. (2019b), Lin et al. (2019), and this work. The dark blue shaded region in the bottom left panel shows the continuous upper and lower limit measurements provided in Kareta et al. (2019) for the production of CN during this period. The right two panels show our observations with MUSE, Trappist North and Trappist South. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590356108213-61LFD288W84BPCJPDTIH/C2CNRatio.jpg 2I/Borisov Pre-perihelion ratio of the production rates of C2 and CN in 2I/Borisov in 2019 September–November; its perihelion is 2019 December 8. We show the measurements and upper limits in Fitzsimmons et al. (2019), Kareta et al. (2019), Opitom et al. (2019b), Lin et al. (2019), and this work as a function of 2I/Borisov’s heliocentric distance in the left panel. The two black points show the ratios measured with the observations with MUSE on November 14-15 and November 25, when both CN and C2 are detected at high SNR. In the right panel, the purple histograms show the ratio of production rates for comets in the sample presented in A’Hearn et al. (1995). The solid lines indicate the measured values and upper limits for Borisov, with the same color scheme as in the left panel. The black dashed line indicates the commonly accepted definition for carbon depleted comets, log[Q(C2)/Q(CN)]≤ −0.18 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590356087859-XJZJU4E1J2394T2VXYFU/Productionrates.jpg 2I/Borisov Pre-perihelion production rates of C2 (upper) and CN (lower) in 2I/Borisov in 2019 September–November; its perihelion is 2019 December 8. The left two panels show the measurements and upper limits in Fitzsimmons et al. (2019), Kareta et al. (2019), Opitom et al. (2019b), Lin et al. (2019), and this work. The dark blue shaded region in the bottom left panel shows the continuous upper and lower limit measurements provided in Kareta et al. (2019) for the production of CN during this period. The right two panels show our observations with MUSE, Trappist North and Trappist South. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590356108213-61LFD288W84BPCJPDTIH/C2CNRatio.jpg 2I/Borisov Pre-perihelion ratio of the production rates of C2 and CN in 2I/Borisov in 2019 September–November; its perihelion is 2019 December 8. We show the measurements and upper limits in Fitzsimmons et al. (2019), Kareta et al. (2019), Opitom et al. (2019b), Lin et al. (2019), and this work as a function of 2I/Borisov’s heliocentric distance in the left panel. The two black points show the ratios measured with the observations with MUSE on November 14-15 and November 25, when both CN and C2 are detected at high SNR. In the right panel, the purple histograms show the ratio of production rates for comets in the sample presented in A’Hearn et al. (1995). The solid lines indicate the measured values and upper limits for Borisov, with the same color scheme as in the left panel. The black dashed line indicates the commonly accepted definition for carbon depleted comets, log[Q(C2)/Q(CN)]≤ −0.18 https://www.darrylseligman.com/hydrogen-icebergs daily 0.75 2020-05-28 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590702139583-H2GM5R201DCUNVLWVA7M/shutterstock_1137771782.jpg Hydrogen Icebergs https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590413872397-UVZ7T9TFJA5EOMFJN26E/orbit_oumuamua_plotv2.jpg Hydrogen Icebergs Schematic diagram showing ‘Oumuamua’s size and shape evolution due to H2 sublimation and its trajectory through the Solar System. Pairs of orientations at three discrete points on the trajectory are shown in the upper left. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590702198560-00ZFKNJN0UBJUPZK0WKL/AspectRatioEvolvev3.jpg Hydrogen Icebergs Density, mass and aspect ratio evolution for ‘Oumuamua as it travelled through the Solar System. The periastron passage is displayed at a time, t = 0, and the date of detection (Location 2 in Figure 1) is labeled. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590413872397-UVZ7T9TFJA5EOMFJN26E/orbit_oumuamua_plotv2.jpg Hydrogen Icebergs Schematic diagram showing ‘Oumuamua’s size and shape evolution due to H2 sublimation and its trajectory through the Solar System. Pairs of orientations at three discrete points on the trajectory are shown in the upper left. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590702198560-00ZFKNJN0UBJUPZK0WKL/AspectRatioEvolvev3.jpg Hydrogen Icebergs Density, mass and aspect ratio evolution for ‘Oumuamua as it travelled through the Solar System. The periastron passage is displayed at a time, t = 0, and the date of detection (Location 2 in Figure 1) is labeled. https://www.darrylseligman.com/chaotic-binaries daily 0.75 2021-01-22 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1611278793753-71CNDBK1PTKF8L6DZQ9B/chaos_binaries.jpg Chaotic Binaries https://www.darrylseligman.com/self-organized-criticality-in-flares daily 0.75 2022-07-03 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1631963422557-0OPYMI86FB2ALPPSL4HM/sandpile-3.png Self-Organized Criticality in Stars https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1631963590066-RANUYT6GD42NDTMUJ2IG/sandpile-3.png Self-Organized Criticality in Stars - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1631963859354-ZA5U77ZEDTC4YNCQZJ45/hr.png Self-Organized Criticality in Stars - Make it stand out HR Diagram showing all the stars in our sample and their flare rates https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1631963887449-WOS10NYI8X7SC3H43PR2/histograms.png Self-Organized Criticality in Stars - Make it stand out The flair frequency distributions for the stars in our sample organized by stellar mass. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984452396-6SZRPF18XFG7VQW9H00Q/braiding_schematic_V6.png Self-Organized Criticality in Stars - Make it stand out A schematic diagram of three braided flux tubes that cause an incoherent reconnection event - resulting in the merging of opposite signed sequences - that releases energy. In this setup, the two sequences on the left hand side are braided in opposing directions. After the reconnection event, which removes the interchange, the two sequences unwind and release the magnetic energy density that was stored in transverse components of the fields. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984572228-3M4MF65QN8SZ5UE2MJQA/energy_distribution.png Self-Organized Criticality in Stars - Make it stand out The energy distribution of flaring events for a range of η, which corresponds to rotational period.. The energy distribution becomes shal lower as η increases for more rapidly rotating stars. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984780868-GB3NGTZDOGMZN73Q2U0C/data_plus_model_3.png Self-Organized Criticality in Stars - Make it stand out Flare frequency distributions (FFDs) for the flares in our sample, binned by the intensity of the flare in percentage of the star’s normalized flux. The flare amplitude, A, is divided into bins of equal width in log-space (with 5 bins per dex) ranging from −2.5 ≤ log10(A) ≤ 1, and the vertical axis plots the number of flares observed per star per day in each amplitude bin. The top panel shows the distribu- tion of flares on stars with rotation periods, Prot, of < 3 days (522 stars with 11,614 flares total), and the bottom shows the distribution of flares on stars with Prot ≥ 3 days (347 stars with 4,570 flares total). While our sample of slower rotators is incomplete, there is evidence that the more rapidly rotating objects have shallower slopes characterized by more energetic events, which implies stronger winding parity violation. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984839738-JJL8LKCWGK81743Y98XD/corner_3.png Self-Organized Criticality in Stars - Make it stand out The distributions of the best fitting power-law exponent and amplitude cutoff parameter for the slow and fast rotators, from the MCMC fitting process. This shows the full 2D posterior PDF, including both slopes and cutoffs, with histograms showing the marginal 1D PDFs. In the central panel showing the 2D PDF, the shaded regions are the 68%, 90%, and 95% CIs, which visually demonstrate that the CIs are overlapping at 68% confidence. This suggests that the distributions of flares are marginally different for fast and slow rotators. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1631963590066-RANUYT6GD42NDTMUJ2IG/sandpile-3.png Self-Organized Criticality in Stars - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1631963859354-ZA5U77ZEDTC4YNCQZJ45/hr.png Self-Organized Criticality in Stars - Make it stand out HR Diagram showing all the stars in our sample and their flare rates https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1631963887449-WOS10NYI8X7SC3H43PR2/histograms.png Self-Organized Criticality in Stars - Make it stand out The flair frequency distributions for the stars in our sample organized by stellar mass. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984452396-6SZRPF18XFG7VQW9H00Q/braiding_schematic_V6.png Self-Organized Criticality in Stars - Make it stand out A schematic diagram of three braided flux tubes that cause an incoherent reconnection event - resulting in the merging of opposite signed sequences - that releases energy. In this setup, the two sequences on the left hand side are braided in opposing directions. After the reconnection event, which removes the interchange, the two sequences unwind and release the magnetic energy density that was stored in transverse components of the fields. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984572228-3M4MF65QN8SZ5UE2MJQA/energy_distribution.png Self-Organized Criticality in Stars - Make it stand out The energy distribution of flaring events for a range of η, which corresponds to rotational period.. The energy distribution becomes shal lower as η increases for more rapidly rotating stars. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984780868-GB3NGTZDOGMZN73Q2U0C/data_plus_model_3.png Self-Organized Criticality in Stars - Make it stand out Flare frequency distributions (FFDs) for the flares in our sample, binned by the intensity of the flare in percentage of the star’s normalized flux. The flare amplitude, A, is divided into bins of equal width in log-space (with 5 bins per dex) ranging from −2.5 ≤ log10(A) ≤ 1, and the vertical axis plots the number of flares observed per star per day in each amplitude bin. The top panel shows the distribu- tion of flares on stars with rotation periods, Prot, of < 3 days (522 stars with 11,614 flares total), and the bottom shows the distribution of flares on stars with Prot ≥ 3 days (347 stars with 4,570 flares total). While our sample of slower rotators is incomplete, there is evidence that the more rapidly rotating objects have shallower slopes characterized by more energetic events, which implies stronger winding parity violation. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984839738-JJL8LKCWGK81743Y98XD/corner_3.png Self-Organized Criticality in Stars - Make it stand out The distributions of the best fitting power-law exponent and amplitude cutoff parameter for the slow and fast rotators, from the MCMC fitting process. This shows the full 2D posterior PDF, including both slopes and cutoffs, with histograms showing the marginal 1D PDFs. In the central panel showing the 2D PDF, the shaded regions are the 68%, 90%, and 95% CIs, which visually demonstrate that the CIs are overlapping at 68% confidence. This suggests that the distributions of flares are marginally different for fast and slow rotators. https://www.darrylseligman.com/coriolis-effects-in-stellar-flares daily 0.75 2022-01-24 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642985350071-YVKJUB4PYYGHBMIL94H5/schematicv2_scattering.png Transitioning Centaurs https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642985556291-1AEGABOCXM72B3VKR1G1/MissionLD2_fromL2.png Transitioning Centaurs - Make it stand out A fiducial trajectory from the Jupiter-Sun L2 point to orbit match LD2. The orbits of LD2, Jupiter and the hypothetical spacecraft are shown in blue, red and grey respectively. Points along each trajectory correspond to evenly spaced sampling of the trajectory through time, where large and small circles correspond to two different cadences. The spacecraft is sent in 2061 before LD2 experiences its closest approach to Jupiter, flies for 2 years, and rendezvous in 2063, after the close approach when the Delta V between Jupiter and LD2 is small, in order to optimize the orbit matching efficiency. The required Delta V from Jupiter's co-orbital location is 0.9 km/s. https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642985556291-1AEGABOCXM72B3VKR1G1/MissionLD2_fromL2.png Transitioning Centaurs - Make it stand out A fiducial trajectory from the Jupiter-Sun L2 point to orbit match LD2. The orbits of LD2, Jupiter and the hypothetical spacecraft are shown in blue, red and grey respectively. Points along each trajectory correspond to evenly spaced sampling of the trajectory through time, where large and small circles correspond to two different cadences. The spacecraft is sent in 2061 before LD2 experiences its closest approach to Jupiter, flies for 2 years, and rendezvous in 2063, after the close approach when the Delta V between Jupiter and LD2 is small, in order to optimize the orbit matching efficiency. The required Delta V from Jupiter's co-orbital location is 0.9 km/s. https://www.darrylseligman.com/outreachteaching daily 0.75 2024-01-26 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1499717967874-S3HPRZWRBVY46IQQ1UWV/image-asset.png Outreach & Teaching "Darryl was a great TA and very supportive on particularly difficult pset questions. In addition he was able to teach us new information not necessarily covered in class in interesting ways. He was very understanding when people struggled with the homework and did his best to be an available resource whenever we needed help." "Darryl was a fantastic TA - he was a fair grader, gave appropriate and helpful feedback, and scheduled and conducted very helpful sections." "Darryl is terrific, truly a wonderful Teaching Fellow. I enjoyed getting to know him and wish him the best. He's bright, kind, genuinely interested in having his students understand the material, and delightful to listen to." "He was very attentive and encouraged everyone to participate in section. In teaching, he was able to find a balance between making things too hard and too easy, such that he helped us with the material while still making sure we were challenged. He could improve by organizing and assigning material to particular sections, and ensuring that we stick to each topic in a given time period so that we can cover all the material."   https://www.darrylseligman.com/current-projects daily 0.75 2024-01-26 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1499710674823-GFUXMR5XZHYQ83NCCPW4/image-asset.png Research Highlights https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642985113834-LTU9HVWAOCJZHPRSE5II/image-asset.png Research Highlights - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://www.darrylseligman.com/new-index daily 0.75 2024-01-26 https://www.darrylseligman.com/home daily 0.75 2024-01-26 https://www.darrylseligman.com/home-1 daily 1.0 2026-02-12 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1590622725655-WIZ7PAC1K1BJKMHJO18E/headshot_seligman.png https://www.darrylseligman.com/home-1/project-five-748cx-xdxpp monthly 0.5 2024-01-27 https://www.darrylseligman.com/home-1/project-four-l3zw3-26klz monthly 0.5 2024-01-27 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/5e1a0b11-a036-449e-9d00-e9f3c0ee5d43/volcanic_planets_homogeneous2.png https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/64e56dc9-cd1b-4020-ab49-89cd0b8ea43c/volcanism+copy.jpg https://www.darrylseligman.com/home-1/project-three-sng7y-52s2b monthly 0.5 2024-01-27 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1631963859354-ZA5U77ZEDTC4YNCQZJ45/hr.png https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1642984452396-6SZRPF18XFG7VQW9H00Q/braiding_schematic_V6.png https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1499713872012-SQLHDWGZJEDVZQZAQ51A/flare.jpg https://www.darrylseligman.com/home-1/project-two-ky966-3azgc monthly 0.5 2024-01-27 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/26e5030e-f557-497b-89b4-2bbdf855a5e7/Artists_concept_of_cigar-shaped_space_rock.jpeg https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/81babf50-adbb-4237-9c6d-1597ebab7a81/0292_637862299220184220.jpeg https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/e9585460-8c49-4a49-8916-6aa59b1603ee/psjac58fef4_hr.jpeg https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/c744a837-ca93-4b2d-ab9e-fb38aa3d11af/schematic_diagramv3.jpeg https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1df4edc3-6c75-4748-9b80-75fe75a31fba/d41586-023-00797-5_24644276.png https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/1517166180191-HHVQMLFUE7WMMQGMM2ST/intercept.jpg https://www.darrylseligman.com/home-1/project-one-f5w4d-wbde2 monthly 0.5 2024-01-27 https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/8601c5fb-637c-457d-9537-5d525adceb07/kybox2.jpg https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/267a7013-9eac-4ecf-8ab1-7b4b285aeaac/mag_acceleration+copy.jpg https://images.squarespace-cdn.com/content/v1/5963a26203596ebd982e6b51/f3d78891-e18d-43ab-9ff8-5f6e6576ccbf/gateway+copy.jpg