Report - School of Physics

2.3 Summary of Prospects 2005–2015
The prospects for the main search experiments described in this section are summarised
in Table 5. This table presents only a simplified picture of planet detection
capabilities, ignoring the comparative importance of finding large numbers of exoplanets
with only an estimation of M sin i or r/R, or more comprehensively characterising
a smaller number of planets (with mass, radius, albedo, and age). It also
ignores the fact that different objects will be detected by different methods, and
that different methods supply complementary astrophysical information.
Table 5: Predictions for the numbers of planet detections out to 2015 according to the major experiments
currently planned, and the planet mass range given in the first column (M ⊕ ∼ 0.003M J ).
The predictions depend sensitively on the (unknown) frequency of occurrence of (especially the
lower-mass) planets, uncertain sample sizes, stellar jitter, etc. These are generally assessed somewhat
differently for each project, and details are given in the accompanying text. The numbers
must be understood as indications of possible developments only.
M Planet 2004 2008–10 2008–10 2008 2010 2010–12 2015 2016 2016
(M J ) Radial Velocity Transits COROT Kepler Eddington SIM Gaia
(ground) (ground) astrom photom
(a) (b) (c) (d) (e) (f) (g) (h) (i)
1–10 90 200–250 100–1000 5–15 see below 200 15 000 3000
0.1–1 30 150–200 0 50–150 see below 50 5 000 0
0.01–0.1 0 10–20 0 10–30 see below 20 0 0
0.003–0.01 0 0 0 0–3 0–640 0–660 0–5 0 0
The columns of the table give results expected for: (a) the present situation, dominated by radial
velocity detections; (b) the situation projected in the year 2010 from ground-based radial
velocity observations (estimates by Udry, see Section 2.1.1); (c) ground-based transit detections:
hot Jupiters extrapolated from Horne (2003); (d) COROT (estimates by Bouchy & Rauer, see
Section 2.2.1); (e) Kepler (taken from the Kepler www site, see Section 2.2.1); (f) Eddington (estimates
by Favata, see Section 2.2.1); (g) SIM (estimates by Perryman from the surveys noted in
Section 2.2.2); (h–i) Gaia astrometric and photometric detections (see Section 2.2.2).
The estimated detections for Eddington are not available as a simple function of mass, but have
been classified (as detailed under the relevant section) as follows, with the same assessment then
made for the Kepler mission using the same assumptions:
– Eddington: 14 000 planets in total (in 12 500 systems)
– Kepler: 51 000 planets in total
– Eddington: 8000 hot planets, 5600 with R > 5R ⊕
– Kepler: 30 000 hot planets, 22 000 with R > 5R ⊕
– Eddington: 660 Earths (0.5 < R < 2.0R ⊕ )
– Kepler: 19 000 Earths (0.5 < R < 2.0R ⊕ )
– Eddington: 160 habitable zone planets, of which 20 ‘Earths’
– Kepler: 530 habitable zone planets, of which 35 ‘Earths’
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