P4-1 Precision Radial Velocity Spectrometer (PRVS)

• 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.

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.

4. TRACEBILITY2. IMPACT ON THE DISK

3. CIII] emissivity (stellar 1kG dipolar field)

Stellar Wind

Episodic Plasmoids Ejection

Disk Wind

Disk dynamo in action No disk dynamo

1. THE BASICS

Gómez de Castro & von Rekowski, 2007

z-axis

r-axis

z-axis

Propagation of 2MeV electrons in the inner

border of the disk

DiskMidplane

•Most of the energy is releasead along the incidence direction within a beam of 2 107 cmand 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

1993 2001

Optically thin lines emitted by the plasma

@Tє[3000-300,000]K -> UV wavelengths

Tracing the interaction of the stellar wind with the

young planetary disk material

Detecting the output from accretion and outflow

(densities and temperatures are similar)RY Tau: Gómez de Castro & Verdugo, 2007,ApJL

AB Dor: Gómez de Castro 2002

A Clear Signature of Star-Disk Interaction in NGC 2264 and the Orion Nebula Cluster

P4-4 Cieza & Baliber

ORION

NGC 2264 ONC

MC MODEL

A Search for Disk-Locking in Chamaeleon I and Taurus-AurigaA Search for Disk-Locking in Chamaeleon I and Taurus-AurigaD. C. Nguyen, R. Jayawardhana, M. H. van Kerkwijk, A. Brandeker, A. Scholz

University of Toronto

D. C. Nguyen, R. Jayawardhana, M. H. van Kerkwijk, A. Brandeker, A. Scholz

University of Toronto

Cha I Tau-Aur

1. Accretors and non-accretors are clearly delineated by H 10% width2. Preliminary results show a smaller fraction of fast rotators that are accreting than not

accreting in both samples3. Our sample has smaller fraction of fast rotators than Orion Molecular Cloud population

sampled by Rebull et al. (2006, ApJ, 646, 297)

1. Accretors and non-accretors are clearly delineated by H 10% width2. Preliminary results show a smaller fraction of fast rotators that are accreting than not

accreting in both samples3. Our sample has smaller fraction of fast rotators than Orion Molecular Cloud population

sampled by Rebull et al. (2006, ApJ, 646, 297)

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

Imaging survey of optically visible Herbig stars from Gemini North & South (12 m & 18 m)

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

•8 sources resolved @ FWHM &

lower brightness level

•2 sources resolved @ lower brightness level

•9 sources unresolved

Exploring the Geometry of Protoplanetary Disks in the Mid-Infrared

Mariñas, N., Telesco, C.M., Packham, C., and Fisher, R.S.

Compact sources => younger, more massive, higher mass accretion rates!

(Proposed evolution of disks by Dullemond & Dominik 2004)

• 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

P4-9Moerchen et al.

P4-11

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 m) & LL (14 – 35 m)

• Are there more stars like HD 69830 ???

Summary of Results

• 19/152 (13%) have IRS excess (87% no excess)

• All excesses at > 14 m

• No spectral features observed (large grains)

• If a star has an IRS excess & 70 m data, then the star also has 70 m excess

• 5 stars with 70 m have NO IRS excess

Lisse et al. 2006