1. Extra-Solar Planets Planetary Physics Summer Term 2004 Lecture 10

2. Or: How to get on the Big Breakfast Show...

3. Extra-Solar Planets Since October 1995, more than 120 planets have been detected around more than 100 stars like the Sun - why the sudden success? None has been seen directly: all found by wobble of parent star caused by orbiting planet - how? None is like the Earth: all have masses more like Jupiter - why?

4. Extra-Solar Planets Definitions: Star: > 0.08 solar masses (80 jupiter masses), powered by H fusion; formed by gravitational collapse, occur singly or in multiples Brown Dwarf: 13 jup < mass < 80 jup, some initial D fusion, then fade; formation and occurrence as normal stars Planets: < 13 jup, no nuclear power source; formed by accretion from protoplanetary disc left behind from formation of parent star

5. In these HST pictures we see disks around stars, but also jets of material being blown out again, especially in the lowest picture (the Rotten Egg nebula). Planets form from the disks.

7. Extra-Solar Planets Methods of detection: Astrometry - long history, no detections Radial velocity surveys - very successful Brightness variations –planet passes in front of star: drop in brightness –gravitational lensing of star by planet: increase in brightness - only way to detect earth-mass planets Interferometry - ground and space missions

8. Extra-Solar Planets Astrometry: Very precise measurements of position of parent star, relative to inertial frame, repeated over many years Centre of mass of system moves in straight line If planet exists, stars motion will have slight wobble about CoM motion - can find size and period of orbit, and mass of planet Massive planets in wide, long-period orbits give largest wobble; nearby stars are best, but effects still too small to measure with present equipment

9. Extra-Solar Planets Radial velocity surveys: Very precise measurements of radial velocity of parent star, using doppler effect Single star will have constant velocity, but if companions are present their orbital motions will be reflected in motion of star about CoM - look for periodic oscillations in radial velocity

10. Extra-Solar Planets Limits of radial velocity measurements: Can find period, eccentricity and M P sin i, where i is inclination of orbit to line of sight (just measure the radial velocity, = V 1 sin i, where V 1 is the orbital motion of the star – see Lecture 5) Can not measure i : need transits for this Motion largest for large masses, short periods Limit set by oscillations in stars size (2-3 m/s) Earth mass in 1-yr orbit gives only 0.1 m/s

11. Extra-Solar Planets Gravitational lensing: Parent star (lens) focuses light of background star as it passes in front of it: Observer Star Lens (and planet) time Planet causes blip in slow light variation

12. Micro-lensing simulation

13. Extra-Solar Planets History I: 1950 - 1970: various false astrometric claims of Jupiter size companions, e.g. to Barnards star (van de Kamp) 1980s: pioneering radial velocity survey by Campbell & Walker - precision of 13 m/s, but no detections (small sample - only 21 stars)

14. Extra-Solar Planets History II: Late 1980s, early 1990s: several large, high precision RV surveys began - Marcy & Butler (Lick), Mayor & Queloz (OHP), Cochran & Hatzes (McDonald) 1995 October 6: first extrasolar planet round a normal star announced by Swiss team (2 found earlier around a pulsar)

15. Marcy and Butler found this wobble in the motion of the star 51 Pegasi, and were able to find a period of just over 4 days.

16. This shows the same observations, but now with all the different orbits superimposed to show the variation better.

17. Extra-Solar Planets What did we expect? small mass planets (Earth-like) close to star: radiation should evaporate most abundant element, hydrogen, leaving small rocky planets massive gaseous planets (Jupiter-like: mainly hydrogen) far enough out to avoid evaporation - so expect long periods circular orbits, as in solar system stars like the Sun

18. Extra-Solar Planets What did we find? massive planets close to star! many eccentric orbits! no earth-like planets stars generally richer in heavy elements (such as iron) than the Sun Of the more than 100 found so far, at least 10 of the early one were around targets suggested by Kevin Apps (Sussex u.g.)

19. Extra-Solar Planets Kevins involvement: November/December 1997 - e-mailed Marcy requesting list of 300 targets for Keck 10-m, found 30 unsuitable and suggested 30 replacements Became responsible for generating new targets (in 1999, nearly 400 of the 900 targets were his) and for searching the literature for their properties April 1999: went to San Francisco to observe with a Lick Observatory telescope August 1999: observed on Hawaii (Keck) May do PhD with Marcy from 2004

20. Extra-Solar Planets Current results: 122 planets with masses 0.12 to 16.9 jup 41 hot Jupiters (Jupiter mass, close to star: a < 0.4 AU) 57 Jupiter analogues (Jupiter mass, far from star: P > 1 yr) 70 eccentric planets (high eccentricity orbits: e > 0.2) 13 systems with multiple planets (2 have 3)

21. The first 22 planets were very close to their parent stars

22. Three planets around Upsilon Andromedae: first solar system

23. Extra-solar Planets Catalog Including Candidates to be confirmed (sorted by increasing mass) From the Extrasolar Planets Encyclopaedia http://www.obspm.fr/planets Extrasolar Planets Encyclopaedia Maintained by ©,1996 Jean Schneider Observatoire de Paris jean.schneider@obspm.fr ©,1996 Jean Schneider Update: 10 May 2001 ( Warning: As there is no clear consensus about the definition criteria of planets, `super-planets' and brown dwarfs (mass, formation,...), this Catalog includes only (with a few exceptions) objects lighter than 13 M Jup (no deuterium burning)). The Catalog below contains four tables (the objects are sorted for each by increasing mass of the lightest planet in the system): 1.Confirmed planets around main sequence stars 1.HD 83443 update 2 Nov. 00HD 83443 2.HD 16141 update 22 Nov. 00HD 16141 3.HD 168746 update 4 May 00HD 168746 4.HD 46375 update 29 Mar. 00HD 46375 5.HD 108147 update 4 May 00HD 108147 6.HD 75289 update 16 Apr. 01HD 75289 7.51 Peg update 16 Apr. 0151 Peg 8.BD -10 3166 update 27 Apr. 00BD -10 3166 9.HD 6434 update 22 Nov. 00HD 6434 10.HD 187123 update 6 Jul. 00HD 187123 11.HD 209458 update 25 Apr. 01HD 209458 12.upsilon And update 7 May. 01upsilon And 13.HD 192263 update 22 Nov. 00HD 192263 14.epsilon Eridani update 27 September 00epsilon Eridani 15.HD 38529 update 22 Nov. 00HD 38529 16.HD 179949 update 20 Apr. 01HD 179949 17.55 Cnc update 22 Nov. 0055 Cnc 18.HD 82943 update 10 May. 01HD 82943 19.HD 121504 update 21 August 00HD 121504 20.HD 37124 update 22 Nov. 00HD 37124 21.HD 130322 update 30 Mar. 00HD 130322 22.rho CrB update 6 Apr. 01rho CrB 23.HD 52265 update 22 Nov. 00HD 52265 24.HD 177830 update 22 Nov. 00HD 177830 25.HD 217107 update 6 Jul. 00HD 217107 26.HD 210277 update 22 Nov. 00HD 210277 27.HD 27442 update 16 Dec. 00HD 27442 28.16 Cyg B update 18 Jan. 0116 Cyg B 29.HD 74156 update 4 Apr. 01HD 74156 30.HD 134987 update 22 Nov. 00HD 134987 31.HD 160691 update 16 Dec. 00HD 160691 32.HD 19994 update 21 August 00HD 19994 33.Gliese 876 update 7 May. 01Gliese 876 34.HD 92788 update 22 Nov. 00HD 92788 35.HD 8574 update 4 Apr. 01HD 8574 36.HR810 update 22 Nov. 00HR810 37.47 Uma update 22 Nov. 0047 Uma 38.HD 12661 update 22 Nov. 00HD 12661 39.HD 169830 update 22 Nov. 00HD 169830 40.14 Her update 16 Apr. 0114 Her 41.GJ 3021 update 22 Nov. 00GJ 3021 42.HD 80606 update 4 Apr. 01HD 80606 43.HD 195019 update 22 Nov. 00HD 195019 44.HD 213240 update 4 Apr. 01HD 213240 45.Gl 86 update 22 Nov. 00Gl 86 46.tau Boo update 16 Dec. 00tau Boo 47.HD 50554 update 4 Apr. 01HD 50554 48.HD 190228 update 22 Nov. 00HD 190228 49.HD 168443 update 11 Jan. 01HD 168443 50.HD 222582 update 22 Nov. 00HD 222582 51.HD 28185 update 4 Apr. 01HD 28185 52.HD 178911 B update 4 Apr. 01HD 178911 B 53.HD 10697 update 22 Nov. 00HD 10697 54.70 Vir update 22 Nov. 0070 Vir 55.HD 106252 update 4 Apr. 01HD 106252 56.HD 89744 update 22 Nov. 00HD 89744 57.HD 141937 update 4 Apr. 01HD 141937 58.HD 114762 update 22 Nov. 00HD 114762 2.Confirmed planets around pulsars 1.PSR 1257+12 update 28 Mar. 01PSR 1257+12 2.PSR B1620-26 update 29 July 99PSR B1620-26 3.Disks (potentially protoplanetary or associated to planets) (sorted by distance to the Sun) 1.Beta Pictoris update 2 Sep. 98Beta Pictoris 2.L 1551 update 2 Oct. 98L 1551 3.BD +31 o 643 (disk; to be confirmed) update 10 mar. 97BD +31 o 643 4.Unconfirmed, doubtful, unpublished or invalidated objects. 1.W 3 (OH) update 28 Oct. 99W 3 (OH) 2.HR7875 update 15 Jul. 1998HR7875 3.Geminga (invalidated) update 8 Sep. 99Geminga 4.PSR 0329+54 (Very doubtful) update 28 Apr. 99PSR 0329+54 5.PSR 1828-11 (unpublished data)PSR 1828-11 6.Q0957+561 A (to be confirmed)Q0957+561 A 7.Lalande 21185 (data unpublished) update 5 dec. 97Lalande 21185 8.CM Dra (to be confirmed) update 25 mar. 00CM Dra 9.Alpha Tau (to be confirmed) update 4 Dec. 97Alpha Tau 10.TMR-1C (invalidated) update 3 Apr. 2000TMR-1C 11.98-BLG-35 (to be confirmed) update 7 mar. 200198-BLG-35 12.95-BLG-3 (to be confirmed) update 23 dec. 9695-BLG-3 13.97-BLG-41 (to be confirmed) update 4 nov. 9997-BLG-41 14.94-BLG-4 (to be confirmed) update 23 dec. 9694-BLG-4 5.21 stars with NO planet found (Walker et al.)NO planet found 1.- Confirmed planets (and/or brown dwarfs) (note 1: for planets detected by timing and radial velocity, only the product M x sini is known) 2.- Confirmed pulsar planets StarM[.sini] Jup. mass:(J) Earth mass:(E) (note 1) Semi- maj. Axis (AU) Period years(y) days(d) Ecc.Incli n. (deg) Radiu s (Earth rad.) PSR 1257+12 PSR 1257+12 ~ 300 pc 0.015 (E) 3.4 (E) 2.8 (E) ~ 100 (E) 0.19 0.36 0.47 ~ 40 25.34 (d) 66.54 (d) 98.22 (d) ~ 170 (y) 0.0 0.018 2 0.026 4 - -------- -------- PSR B1620- 26 PSR B1620- 26 3.8 kpc 1.2 < M.sini < 6.7 (J) 10 - 6461.8 - 389 (y) 0. - 0.5 -- 4.- Unconfirmed, doubtful or unpublished objects StarM[.sini] Jup. mass:(J) Earth mass:(E) (note 1) Semi-maj. Axis (AU) Period years(y) days(d) Ecc.Incli n. (deg) Radi us (Eart h rad.) HR7875 HR7875 25 pc F8V V = 5.12 0.69(J)-42.5 (d)0.429-- PSR 1828-11 PSR 1828-11 3.6 kpc 3 (E) 12 (E) 8 (E) 0.93 1.32 2.1 0.68 (y) 1.35 (y) 2.71 (y) ------ ------ ------ Q0957+56 1 Q0957+56 1 2.4 Gpc (z = 0.39) ~ a few (E) ----- Lal. 21185 Lal. 21185 2 pc M2 V = 7 0.9 (J) 1.6- 5.8 (y) 30 ? (y)--- CM Dra CM Dra 14.7 pc M4.5/M4. 5 V = 12.9 ------ Alpha Tau Alpha Tau 20 - 25 pc K5III V = 0.86 11 (J)1.3 - 1.4653.8 (d)0.182 #177 0.065 ?- TMR-1C TMR-1C ~130 pc V = ? 2- 3 (J) ?> 1,500> 40,000 (y) ??~1 R J 98-BLG- 35 98-BLG- 35 ~ 5 kpc ~ 0.4 - 1.5 (E) 1.5 or 2.3???- 95-BLG-3 95-BLG-3 ~ 5 kpc ~ 2 (J)> 5 - 10 ?---- 94-BLG-4 94-BLG-4 ~ 5 kpc ~ 5 (J)~ 1---- Beta Pic Beta Pic 18 pc A5V V = 3.8 -> 62000 (d)-< 1 o ~ 16 BD +31 o 643 BD +31 o 643 330 pc B5V, B5V V = 8.5, 8.5 diskrad. disk: 6,600 --< 10 o - W 3 (OH) W 3 (OH) 3 kpc pc O8 star V = ? 10 -4 ? (E)2,000?---- Back to the Extra-solar Planets Encyclopedia The majority of the planets found so far have orbital radii less than 1 AU: 35% of them are less than 0.4 AU, although there is a growing number with larger radius, including one beyond Jupiter.

24. The majority of planets (~60%) have masses between 1 and 8 Jupiter masses, but there are now many known (~30%) with masses less than that of Jupiter (down to 0.12 jup: ~0.4 sat). But only lower limits are known without knowing i: needs transits. Mass distribution for extra-solar planets

25. 7 November 1999: first-ever planetary transit observed for sun-like star HD 209458 by Henry, Marcy, Butler and Vogt

26. The radial velocity group of Marcy, Butler and Vogt found this evidence of a wobble in the motion of the star and alerted Greg Henry to observe its brightness.

28. This is the 0.8m Automatic Photoelectric Telescope of the Tennessee State Universitys Fairborn Observatory in southern Arizona, which was used by Greg Henry to observe the planetary transit. An attempt to verify the result on November 14 was clouded out, but other groups later verified it.

29. Average of four HST transit observations

30. Three more transits have now been detected, in the microlensing surveys, and one genuine microlensing event: One of the three transit events…. ….and the microlensing event

31. Extra-Solar Planets The Future: Continuing radial velocity searches (lower mass planets? more solar systems?) Transits – now four cases Gravitational lensing Ground-based astrometry Direct imaging? Difficult from the ground Space-based imaging (e.g. DARWIN) Space-based astrometry (e.g. GAIA)

32. An artists impression of the proposed 6-spacecraft Darwin mission, due to fly in about 2010. Each craft contains a large IR telescope, and they are spread over distances of 40 to 500 metres.

34. Extra-Solar Planets Where next? Who knows!