P4-1 Precision Radial Velocity Spectrometer (PRVS)

1. P4-1Precision Radial Velocity Spectrometer(PRVS) H. Jones (Hertfordshire), J. Rayner (Hawaii), L. Ramsey (PSU), B. Dent (UK ATC), A. Longmore (UK ATC), B. Vacca (Hawaii), M. Liu (Hawaii), A Webster (UK ATC), A. Wolscznan (PSU), et al. • 2nd generation (“Aspen”) instrument for Gemini • R=70,000, 1.0-1.8 m, RV stability < 1 m/s • Goal: Find terrestrial (HZ) planets around M dwarfs.

2. 1. THE BASICS 3. CIII] emissivity (stellar 1kG dipolar field) Disk dynamo in action No disk dynamo Episodic Plasmoids Ejection z-axis Stellar Wind Disk Wind r-axis Gómez de Castro & von Rekowski, 2007 2. IMPACT ON THE DISK 4. TRACEBILITY Propagation of 2MeV electrons in the inner border of the disk Tracing the interaction of the stellar wind with the young planetary disk material • Most of the energy is releasead • along the incidence direction • within a beam of 2 107 cm • and a depth of 8 107cm • (disk height 109 cm) • Energy spreading has to be done through the Hard Bremsstrahlung radiation energy cascade. Selective absorption by disk molecules produces PDRs • A non-negligible source of ionization further than the atmosphere. • A source of high energy electrons to interact with molecules collisionally • Gómez de Castro & Antonicci, 2007 Optically thin lines emitted by the plasma @Tє[3000-300,000]K -> UV wavelengths z-axis 1993 2001 Disk Midplane AB Dor: Gómez de Castro 2002 Detecting the output from accretion and outflow (densities and temperatures are similar) RY Tau: Gómez de Castro & Verdugo, 2007,ApJL

4. A Clear Signature of Star-Disk Interaction in NGC 2264 and the Orion Nebula Cluster P4-4 NGC 2264 ONC MC MODEL ORION Cieza & Baliber

5. Cha I Tau-Aur A Search for Disk-Locking in Chamaeleon I and Taurus-Auriga D. C. Nguyen, R. Jayawardhana, M. H. van Kerkwijk, A. Brandeker, A. Scholz University of Toronto Accretors and non-accretors are clearly delineated by H 10% width Preliminary results show a smaller fraction of fast rotators that are accreting than not accreting in both samples Our sample has smaller fraction of fast rotators than Orion Molecular Cloud population sampled by Rebull et al. (2006, ApJ, 646, 297)

6. Spitzer Observations of h &  Persei: Protoplanetary Disk Evolution & Planet Formation at 10-15 Myr • stellar mass-dependent evolution of disks • λ – dependent evolution of disks • Terrestrial-Zone Debris Disks T. Currie, et al. 2007, ApJ, 659, 599 Poster P4-6

8. Exploring the Geometry of Protoplanetary Disks in the Mid-Infrared Mariñas, N., Telesco, C.M., Packham, C., and Fisher, R.S. Imaging survey of optically visible Herbig stars from Gemini North & South (12 mm & 18 mm) Mid-IR extended emission is resolved in 10/20 sources with sizes 100 to 500 AU There is an additional compact unresolved component in all sources (Proposed evolution of disks by Dullemond & Dominik 2004) • 8 sources resolved @ FWHM & • lower brightness level • 2 sources resolved @ lower brightness level • 9 sources unresolved Compact sources => younger, more massive, higher mass accretion rates!

9. P4-9 Moerchen et al. • Our study: image thermally-emitting dust in nearby (<100 pc) debris disk candidates (identified by Spitzer/MIPS photometry) with subarcsecond resolution • Observing program of 20 sources at 10 & 18 microns at Gemini is near completion • 2 sources spatially resolved so far: Zeta Lep & HD 32297

11. P4-11

12. A Search for Warm Dust in the Habitable Zones Around Solar-like Stars David Ciardi, Samantha Lawler, Chas Beichman, Rachel Akeson (Michelson Science Center/Caltech) Geoff Bryden, Karl Stapelfeldt, Angelle Tanner (Jet Propulsion Laboratory) • Goals • Survey 152 FGK(M) stars for warm dust • Spitzer IRS SL (7 – 14 mm)& LL (14 – 35 mm) • Are there more stars like HD 69830 ??? • Summary of Results • 19/152 (13%) have IRS excess (87% no excess) • All excesses at l > 14 mm • No spectral features observed (large grains) • If a star has an IRS excess & 70 mm data, then the star also has 70 mm excess • 5 stars with 70 mm have NO IRS excess Lisse et al. 2006