Post-main-sequence planetary system evolution

Important forces in post-MS systems. These charts represent just a first point of reference. Every system should be treated on a case-by-case basis. Magnetic fields include those of both the star and the SB, and external effects are less penetrative in the GB phases because they are relatively short.

Useful values for 12 different stellar evolution tracks. I mapped the first column to the second by using appendix B of [26], and then created the remaining columns by using the sse code [27] by assuming its default values (which includes Solar metallicity). The four highlighted rows roughly represent the range of the most common progenitor stars for the present-day WD population in the Milky Way.

Cosmetically enhanced version of fig. 1 of [98]. Shown are the sinking times of six metals in WD atmospheres. These times are orders of magnitude less than the WD cooling ages. The sinking timescales of DA WDs younger than about 300 Myr are days to weeks.

Cosmetically reconstructed version of the top panel of fig. 8 of [96]. The blue downward triangles refer to upper limits. The plot illustrates that accretion rate appears to be a flat function of WD cooling age: pollution occurs at similar rates for young and old WDs.

Histograms of the accumulated mass of rocky substellar bodies that were accreted onto white dwarfs during the last Myr or so, including both detections and limiting values. Differently coloured bars refer to three different WD samples (brown: data from [93] assuming that Ca represents 1.6% of the mass of the accreted bodies, similar to the corresponding mass fraction of the bulk Earth—see table 3 of [102]; blue: data displayed in fig. 12 of [103]; red: data displayed in fig. 9 of [104]). The panels are separated according to sample size (see y-axis). For observational subtleties associated with the data, see the corresponding papers. The bin sizes are according to the Solar system objects displayed in green, with masses given on the top axis. This plot demonstrates that pollution may arise from a wide variety of objects.

Exact reproduction of fig. 5 of [122]. This image is a velocity space map of the gaseous component of the debris disc orbiting the WD SDSS J1228+1040. The subscripts x and y refer to their usual Cartesian meanings, and the WD is located at the origin. Observations at particular dates are indicated by solid white lines. The image suggests that the disc is highly non-axisymmetric and precessing on decadal timescales.

Cosmetically enhanced version of fig. 1 of [228]. The prospects for survival of Jupiter-mass planets orbiting a RGB star with M⋆(MS)=1.5 M⊙ and evolving due to tides and mass loss. The stellar surface is given by the upper curve on the solid red shape. The red planetary tracks end in engulfment, whereas planets on green tracks remain safe. The solid black curve shows the closest planet that survives, and the dotted black curve illustrates the closest planet that is not visually affected by RGB tides on the scale of this plot.

Cosmetically enhanced version of fig. 3 of [30]. The prospects for survival of Jupiter-mass planets (a) and Earth-mass planets (b) orbiting a AGB star with M⋆(MS)=2.0 M⊙ and evolving due to tides and mass loss. Unlike in figure 8, here the stellar surface pulses. (a) Illustrates that surviving Jovian-mass planets must begin their orbits at least 20 per cent further away than the maximum stellar radius. (b) Earth-mass planets with starting orbits that are within the maximum stellar radius can survive.

Cosmetically enhanced version of the lowest panel of fig. 4 of [32]. How GB evolution of a M⋆(MS)=2.9 M⊙ star depletes a debris disc due to collisional evolution alone. The legend indicates the initial disc masses. The solid lines correspond to {r=10 AU,rd(min)=7.5 AU, rd(max)=12.5 AU}, the dotted lines correspond to {r=50 AU, rd(min)=37.5 AU, rd(max)=62.5 AU} and the dashed lines correspond to {r=100 AU, rd(min)=75 AU, rd(max)=125 AU}.

Cosmetically enhanced version of fig. 2 of [59]. How the GB-induced expansion of the libration width of the 2 : 1 mean motion resonance between a planet and asteroids induces the latter to be scattered towards and inside of the WD disruption radius. The solid and dashed lines are the libration widths for, respectively, M⋆(MS)=1.0 M⊙ and M⋆(WD)=0.5 M⊙. Note that a couple asteroids near the 3 : 2 mean motion commensurability are also scattered towards the WD and disrupted.

Cosmetically enhanced version of the bottom-rightmost panel of fig. 9 of [24]. I show instability timescales, t_inst, as black dots for individual two-planet simulations with the given initial semi-major axis ratio and all with a parent star of M⋆(MS)=3.0 M⊙. Blue stars indicate that all simulations sampled at that particular semi-major axis ratio were stable over a total of 5 Gyr of evolution. The two coloured horizontal lines represent the RGB and AGB phases, and the upper axis illustrates some mean motion commensurabilities. This plot demonstrates that (i) systems which are stable on the MS may become unstable beyond the MS and (ii) that Lagrange instability on the MS can manifest itself late, right before the RGB phase.

Cosmetically enhanced version of the upper-left panel of fig. 1 of [144]. Late unpacking of four tightly-packed terrestrial planets throughout the MS and GB phases. The orbit meandering which follows scattering instability perturbs the red planet into a likely transit-detectable orbit before it enters the WD disruption radius.

Cosmetically enhanced version of fig. 2 of [70]. How particles of given radii and semi-major axis shrink due to the effects of radiation alone, as a function of WD cooling time.