Nordic-Baltic Astronomy Summer School Tuorla 8 - 18 June 2009 Planet Formation and Exoplanets Lecture 5 Bo Reipurth University of Hawaii Dan Durda Dust Disk around AU Mic Michael Liu 2005 Dusty disks can be found around some young stars with coronography, as for example around the 12 million yr old AU Mic. Planets are probably forming around this star at the moment. Debris disks are continuously rejuvenated by collisions between planetesimals Phobos Mathilde Newborn planets are very luminous Probably a 15 M_Jup brown dwarf If a giant planet is formed in a disk, it rapidly develops structure that leads to other planet formation Armitage & Hansen 1999 If a planet forms early when the disk is still massive, it forms a gap in the disk. The planet feeds through spiral arms from both sides of the gap. The ellipse shows the Roche lobe of the planet Papaloizou et al. 2006 PPV chapter Fomalhaut Extrasolar Planets Reflex motion reveals tug of giant planet Reflex motion reveals tug of giant planet List of known exoplanets: http://media4.obspm.fr/exoplanets/base/index.php The 156 Known Nearby Exoplanets GJ 876 0.018 M 0.60 M 1.9 M GJ 436 0.067 M J J J HD 63454 0.34 M J HD 73256 1.7 M J 55 Cnc J 0.037 M 0.99 M 0.17 M 3.6 M HD 330075 0.61 M J J J J HD 46375 0.22 MJ HD 83443 0.39 MJ HD 2638 0.43 MJ HD 149026 0.31 MJ HD 187123 0.52 MJ HD 179949 0.93 MJ BD ⌧10 3166 0.48 MJ HD 88133 0.30 MJ HD 209458 0.68 MJ tau Boo 4.1 M J HD 75289 0.45 MJ HD 76700 0.23 MJ 51 Peg 0.46 MJ HD 149143 1.3 M J HD 49674 0.10 MJ upsilon And 0.68 MJ 1.9 M 3.9 M HD 109749 0.27 MJ J J HD 168746 0.25 MJ HD 68988 J There are 329 exoplanets 1.9 M HD 162020 14. MJ HD 217107 1.3 MJ 20. M HD 130322 1.0 MJ J HD 108147 0.25 MJ GJ 86 3.9 M J HD 27894 J 0.57 MJ known as of April 2009. HD 99492 0.099 M HD 190360 0.056 MJ 1.4 M HD 38529 0.79 M J 13. M J HD 195019 3.6 M J J HD 6434 0.40 MJ HD 192263 0.64 MJ HD 102117 0.16 MJ HD 117618 0.18 MJ rho CrB 1.0 MJ HD 37605 3.1 MJ HD 74156 1.8 MJ 6.1 M HD 3651 0.21 MJ J HD 168443 7.9 M J 17. M 6% of Marcy’s sample show HD 101930 0.29 MJ J HD 178911 B 6.5 M J HD 121504 1.2 MJ HD 114762 11. MJ HD 16141 0.26 MJ HD 216770 J 0.65 MJ planets, and he estimates that HD 80606 4.1 M HD 93083 0.36 MJ 70 Vir 7.4 M J HD 52265 1.0 MJ HD 37124 0.59 MJ 0.57 M 0.63 M GJ 3021 3.5 M J J J HD 208487 0.46 MJ 10-15% of all stars have giant HD 73526 2.3J M 5.5 M HD 82943 1.5J M 1J .7 M HD 8574 1.9 MJ J HD 104985 6.3 MJ HD 150706 0.95 JM HD 169830 J 2.9 MJ 4.0 MJ planets. HD 134987 1.6 M HD 202206 17. MJ 2.4 M HD 12661 2.3 MJ J 1.8 M HD 40979 4.2 MJ J HD 89744 8.5 JM HD 17051 2.0 MJ HD 92788 3.6 MJ HD 28185 5.6 MJ HD 142 1.1 MJ HD 142415 1.6 MJ HD 108874 1.3 MJ 1.0 M HD 128311 2.0 MJ 3.0 M J HD 99109 0.47 JM J HD 210277 1.2 M J HD 154857 1.9 MJ HD 4203 2.1 MJ HD 114783 1.0 MJ HD 188015 1.5 MJ HD 177830 1.6 MJ HD 20367 1.1 MJ HD 27442 1.5 MJ iota Dra 8.7 MJ HD 147513 1.2 MJ HD 222582 5.1 MJ HD 65216 1.2 MJ HD 19994 1.6 MJ HD 160691 1.7J M 1.4 M HD 141937 9.7 MJ J HD 183263 3.7 MJ HD 23079 2.4 JM HD 47536 5.1 MJ HD 4208 0.79 JM HD 114386 1.2 M J 16 Cyg B 1.7 MJ HD 41004 A 2.7J M HD 137510 23.J M HD 45350 0.99 JM HD 213240 4.7 MJ HD 111232 6.6 MJ HD 190228 3.6 JM HD 10647 0.77 MJ HD 114729 0.93 JM 47 UMa 2.7 M J 1.5 M gamma Cep 1.7 MJ J HD 10697 6.3 MJ HD 164922 0.37 MJ HD 2039 6.1 MJ HD 50554 4.3 MJ HD 136118 12. JM HD 216437 2J.2 M HD 216435 1.2 MJ HD 196050 2.9 MJ HD 106252 7.0J M 14 Her J4.9 M HD 23596 8.0 MJ HD 142022 J 4.7 MJ 0 1 2 3 4 5 California Carnegie Orbital Semimajor Axis (AU) Planet Search Planets vs. Stellar Metallicity The extreme heating of hot Jupiters causes powerful winds and turbulence in their atmospheres The Transiting Planet around HD 209458 Text Brown et al. 2001 The Escaping Atmosphere of HD 209458b During transit, a signature of the atmosphere of HD 209458b has been detected in Sodium as an added absorption, in atomic Hydrogen as a 15% extra absorption in the stellar Lyman α line, and in oxygen and carbon as 13% and 7% absorptions. It appears that some of the atmospheric gases are brought up beyond the Roche lobe, from where they escape. Vidal-Madjar et al. (2003,2004) As of May 20, 2009 a total of 59 transiting exoplanets are known see http://exoplanet.eu/catalog-transit.php Atmospheric Escape from Hot Jupiters More than 10% of exoplanets orbit their stars closer than 0.1 AU. This makes them susceptible to evaporation of their atmospheres. The atmospheric escape critically depends on atmospheric temperatures. If atoms in the tail-end of the Boltzmann distribution can reach beyond the Roche lobe, then they can escape. Lecavelier des Etangs et al. (2004) The figure shows contours of survival times (in log t) and a number of known planets are indicated. HD 209458b is marked as a circle. The triangles are planets that will lose large fractions of their mass. Transits: False Positives The transit candidate Lupus-TR1 turns out to be a faint eclipsing binary blended with a much brighter star. The left image shows one of the survey images and the right image is a high resolution image from the 6.5m Magellan. Such false positives can be weeded out by high resolution spectroscopy. Bayliss et al. 2009 The Kepler Mission Continuously points at a single star field in the Cygnus-Lyra region Monitors 100,000 main-sequence stars for planet transits Mission lifetime 4-6 years Launched March 6, 2009 First Light 8 April 2009 ! As of April 2009, 33 stars are known with 2 or more planets The Upsilon Andromedae System The Holy Grail: Finding terrestrial exoplanets Finding terrestrial planets through microlensing A long-term monitoring project has uncovered a lensing event, in which a background star has brightened by the gravity of an intervening passing star. An additional bump in the light curve indicates the presence of a planet about 5 times as massive as the Earth. The planet and its host star are located not far from the Galactic Center. • In planetary systems with several massive planets, orbits of other planets are likely to Free-floating Planets be unstable • This leads to retention of the most massive planets but ejection of other planets • Such objects will be ‘free floating’, and may account for some of the ultra-low-mass objects seen in young clusters • Even planets in our own Solar System are susceptible to long term instabilities The Fate of Planets The engulfing of close-by planets by their parent stars is an inevitable outcome of stellar evolution during the red giant or asymptotic giant branch phase. As the star expands, a planet will spiral into the star, and be dissipated at the bottom of the convective envelope of the giant star. The considerable energy deposited in the star produces a substantial expansion of the star. The observational signature of a planet being swallowed is an infrared excess and a strong Lithium line. About 4 - 8% of red giants show IR excesses and strong Lithium. Siess & Livio 1999a,b Rising from the Ashes: Pulsar Planets Peale 1993 The Planets around the Pulsar PSR 1257+12 Best orbital solutions by Gozdziewski et al. (2005) Dust Disk around the Pulsar 4U 0142+61 Spitzer has detected a debris disk around the pulsar 4U 0142+61.