Debris Dust Around Main

Sequence Stars et al. (2013) Kalas

Chrisne H. Chen STScI, September 2016 1 Exoplanetary Systems

Exoplanet Observaons

Debris Disk Observaons

2 Outline

• The HR 4796 System • Training Students Using the Keck LWS • Spitzer GTO Programs – A Search for Terrestrial Planetary Debris Systems and Other Planetary Debris Disks – Spectroscopy of Protostellar, Protoplanetary and Debris Disks – Dust Around Main Sequence A-type Stars – The Fabulous Four Debris Disks

3 Early Debris Disk Work Timeline

• 1983 IRAS launches • 1984 Smith & Terrile spaally resolve the β Pic disk in scaered light using a coronagraph • 1986 Gille accurately measures “infrared excess” toward Vega, Fomalhaut and β Pic from pointed IRAS observaons • 1991 Jura discovers HR 4796 IRAS infrared excess • 1991 Telesco and Knacke discover spectroscopic evidence for silicates around β Pic • 1993 Backman review arcle “Main Sequence Stars with Circumstellar Solid Material: The Vega Phenomenon” is published in Protostars and Planets III • 1998 Koerner and Jayawardhana resolve the HR 4796A disk in thermal emission using Keck/MIRLIN and Blanco/OSCIR • 2003 Spitzer launches • 2014 Gemini Planet Imager commissioning HR 4796A Infrared Excess Discovery HR 4796B Secondary Star Discovery

• First esmate for the grain temperature based on simple black body modeling, Tgr = 110 K with a predicon for the distance of the grains from the star, ~40 AU • First grain size constrain (> 10 μm) based on the upper limit for the size of the system (<5” at 20 μm) • First calculaon of the Poynng-Robertson drag lifeme for this disk demonstrang that it must be a debris disk HR 4796A Planetary Companion Constraints

• Central clearing may be created by a planetary mass object

• Speckle observaons constrain the mass to be < 0.125 M¤ The HR 4796A Disk Resolved!

(Le) HST NICMOS F1600W and F1100W coronagraphic images showing discovery of the light scaered from the dust (Schneider et al. 1999)

(Right) Keck MIRLIN and 12.5 and 20.8 μm composite image from Koerner et al. (1998); (Far Right) CTIO Blanco 4-m OSCIR IHW18 from Jayawardhana et al. (1998) of the resolved dust thermal emission. GPI K1-Pol Commissioning Observaons of HR 4796

Perrin et al. 2015

• Total intensity phase funcon appears isotropic (consistent with small parcles) • The North side of the disk is brighter in polarized light (rather than the ansa) • Suggests that the disk is marginally opcally thick Young Stars Possess Dusty Debris Young Stars Possess Dusty Debris Training Students using the Keck LWS

Lipscy & Plavchan (2004) Stellar Wind Drag

• Acve stars have high mass loss rates that can impact the dust dynamics ! $! ! 2 $ ! C0LIR M SW c M d = # 2
+ & " c %" L* % 4πaρ D2 t gr sw = ˙ 3Qsw M sw

€ (1) A Search for Terrestrial Planetary Debris Systems and Other Planetary Debris Disks

• Collaborave GTO project (Low, Werner, Jura, and Gehrz) with each GTO contribung their own program • MIPS 24 and 70 μm observaons of 150 nearby (<150 pc), solar-like members of Upper Centaurus Lupus (UCL) and Lower Centaurus Crux (LCC) as determined from Chen, Jura et al. (2005) Hipparcos observaons (de Led to the discovery of a dozen disks as dusty as β Pic Zeeuw et al 1998.) ScoCen Disks Resolved in Scaered Light

Kalas et al. (2015)

Currie et al. (2015)

HD 106906 Draper et al. (2015) ScoCen Companions Detected in Debris Disks

Kalas et al. (2015)

HD 95086 Rameau et al. (2015) (2) Spectroscopy of Protostellar, Protoplanetary, and Debris Disks • Collaborave GTO project to obtain IRS observaons of 650 young objects in nearby star forming regions • Contributed me to study ~100 IRAS-discovered infrared excess sources (both protoplanetary and debris disks) • IRS Disks program led by Dan Watson (University of Rochester) Sloan et al. (2007) Hypothesized that class C PAH sources contain fragile aliphac materials that have not been subjected to strong UV fields Spectroscopic Constraints on Debris Disks

Dust Spaal Distribuon Dust Composion

HD 172555: glassy silicas (Obsidian and Tekte), steep grain size distribuon with large quanes of fine dust and possible fundamental and first overtone emission from SiO -> Hypervelocity Collision (Lisse, Chen et al. 2009)

Eta Crv: warm, water- and carbon- rich dust in the terrestrial habitable zone -> Period of Late Heavy Bombardment (Lisse, Wya, Chen et al. 2012) • Typically well-fit assuming black • Typically includes silicates and trace bodies consistent with dust located in species indicang how processed parent rings (Jura et al. 2004, Chen et al. bodies are and therefore their origin 2006) (3) Dust Around Main Sequence A-Type Stars

MIPS 24 and 70 μm observaons of 157 Harvard Review A- type stars with • Hipparcos distances < 80 pc • 0.0 > (B-V) > 0.2 mag • M(V) > 1.0 + 5.5 (B-V) Common Warm Dust Temperatures Around Main Sequence Stars

• Includes IRS follow-up observaons of A-type stars with MIPS excess discovered in Jura and Rieke GTO programs

Morales et al. (2011) Herschel Hints at Water Ice

Morales et al. (2013) (4) The Fabulous Four Debris Disks

Collaborave GTO project to obtain mul- instrument observaons of • β Pictoris led by IRS • ε Eridani led by IRAC • Fomalhaut led by General GTOs (Jura, Werner) • Vega led by MIPS Coordinated by Karl Stapelfeldt (JPL) Thank you, Mike… for mentoring and encouraging us, for generously sharing your personal me, your scienfic ideas, and your observaons with us.

Ray Jayawardhana Chrisne Chen Peter Plavchan PhD Harvard 2000 PhD UCLA 2002 PhD UCLA 2006

Farisa Morales Greg Sloan BS UCLA 2003 IRSDisks