Evolution of protoplanetary disks Some new rules for

Evolution of protoplanetary disks Some new rules for planet- and star-formers, from the bounty of the Spitzer and Herschel missions. Dan Watson University of Rochester For the Spitzer Infrared Spectrograph (IRS) Team and the Herschel Orion Protostar Survey (HOPS). H/t to Neal Evans and his Cores to Disks (c 2 d) and DIGIT teams. 1

Outline and conclusions Spitzer-IRS and Herschel-PACS had poor spatial and spectral resolution by Townesgroup standards, but their limitations did not prevent the making of substantial discoveries in the domain of protoplanetary disk evolution and planet formation: q Giant planets form within a few Myr of their stars. q Disks dissipate photoevaporatively in 3 -5 Myr. q Prebiotic molecules are abundant in the planet-formation regions of protoplanetary disks. q Dust in disks settles to midplane during the protostellar phase (< 0. 5 Myr). q Crystalline-dust mass fraction of disks increases with age, 0. 7 -5 Myr. 2

Giant planets form within a few Myr of their stars. q Transitional disks: mid-IR spectral gaps in Class II YSOs = 3 -30 AU, sharp -edged gaps in disks = carved by recently-formed giant planets. q Gap verified: SMA, CARMA, Pd. BI and ALMA. q Time scale consistent with Saturn. q Up to 20% of Class II objects, even in the youngest clusters (e. g. NGC 1333, Orion). q Many TDs in ALMA’s grasp; many of their planets in the grasp of GPI, SPHERE, etc. D’Alessio et al 2005; Calvet et al. 2005; Brown et al. 2007; Espaillat et al. 2007, 2008, 2010, 2012; Kim et al. 2009, 2013; Merin et al. 2010. rgap = 46 AU Espaillat et al. 2007 3

Giant planets form within a few Myr of their stars. q Transitional disks: mid-IR spectral gaps in Class II YSOs = 3 -30 AU, sharpedged gaps in disks = carved by recently-formed giant planets. q Gap verified: SMA, CARMA, Pd. BI and ALMA. q Time scale consistent with Saturn. q Up to 20% of Class II objects, even in the youngest clusters (e. g. NGC 1333, Orion). q Many TDs in ALMA’s grasp; many of their planets in the grasp of GPI, SPHERE, etc. D’Alessio et al 2005; Calvet et al. 2005; Brown et al. 2007; Espaillat et al. 2007, 2008, 2010, 2012; Kim et al. 2009, 2013; Merin et al. 2010. rgap = 49 AU Andrews et al. 2011 4

Giant planets form within a few Myr of their stars. q Transitional disks: mid-IR spectral gaps in Class II YSOs = 3 -30 AU, sharpedged gaps in disks = carved by recently-formed giant planets. q Gap verified: SMA, CARMA, Pd. BI and ALMA. q Time scale consistent with Saturn. q Up to 20% of Class II objects, even in the youngest clusters (e. g. NGC 1333, Orion). q Many TDs in ALMA’s grasp; many of their planets in the grasp of GPI, SPHERE, etc. D’Alessio et al 2005; Calvet et al. 2005; Brown et al. 2007; Espaillat et al. 2007, 2008, 2010, 2012; Kim et al. 2009, 2013; Merin et al. 2010. Iapetus Castillo-Rogez et al. 2013 5

Giant planets form within a few Myr of their stars. q Transitional disks: mid-IR spectral gaps in Class II YSOs = 3 -30 AU, sharpedged gaps in disks = carved by recently-formed giant planets. q Gap verified: SMA, CARMA, Pd. BI and ALMA. q Time scale consistent with Saturn. q Up to 20% of Class II objects, even in the youngest clusters (e. g. NGC 1333, Orion). q Many TDs in ALMA’s grasp; many of their planets in the grasp of GPI, SPHERE, etc. D’Alessio et al 2005; Calvet et al. 2005; Brown et al. 2007; Espaillat et al. 2007, 2008, 2010, 2012; Kim et al. 2009, 2013; Merin et al. 2010. Kim et al. 2013 6

Giant planets form within a few Myr of their stars. q Transitional disks: mid-IR spectral gaps in Class II YSOs = 3 -30 AU, sharpedged gaps in disks = carved by recently-formed giant planets. q Gap verified: SMA, CARMA, Pd. BI and ALMA. q Time scale consistent with Saturn. q Up to 20% of Class II objects, even in the youngest clusters (e. g. NGC 1333, Orion). q Many TDs in ALMA’s grasp; many of their planets in the grasp of GPI, SPHERE, etc. D’Alessio et al 2005; Calvet et al. 2005; Brown et al. 2007; Espaillat et al. 2007, 2008, 2010, 2012; Kim et al. 2009, 2013; Merin et al. 2010. Kim 2013, Ph. D. dissertation, University of Rochester 7

Disks dissipate photoevaporatively in 3 -5 Myr. q Late stage: photoevaporative flow, visible in mid-IR fine structure and recombination lines, particularly [Ne II] and Hu . q Getting there: linear relation between mass-loss rate and accretion rate runs all the way through Class 0 and Class II, as measured with [O I], [Si II] and [Fe II]. Hollenbach said it all along, but: Alexander et al. 2006, Najita et al. 2009, Hollenbach & Gorti 2009, Pascucci et al. 2011, Watson et al. 2015. 8

Disks dissipate photoevaporatively in 3 -5 Myr. q Late stage: photoevaporative flow, visible in mid-IR fine structure and recombination lines, particularly [Ne II] and Hu . q Getting there: linear relation between mass-loss rate and accretion rate runs all the way through Class 0 and Class II, as measured with [O I], [Si II] and [Fe II]. Hollenbach said it all along, but: Watson et al. 2015 Alexander et al. 2006, Najita et al. 2009, Hollenbach & Gorti 2009, Pascucci et al. 2011, Watson et al. 2015. 9

Prebiotic molecules are abundant in the planetformation regions of protoplanetary disks. Well, duh, but now we can see it: q q Water HCN, CO 2, C 2 H 2 PAHs Ice line: the far-infrared lines of water – which would be most prominent in cooler gas at larger r – are much fainter, and ice emission features are observed. e. g. Carr & Najita 2007, Najita et al. 2013, Sargent et al. 2014, Mc. Clure et al. 2015. AA Tau, FM Tau, DH Tau (top-bottom) 10

Prebiotic molecules are abundant in the planetformation regions of protoplanetary disks. Well, duh, but now we can see it: q q Water HCN, CO 2, C 2 H 2 PAHs Ice line: the far-infrared lines of water – which would be most prominent in cooler gas at larger r – are much fainter, and ice emission features are observed. e. g. Carr & Najita 2007, Najita et al. 2013, Sargent et al. 2014, Mc. Clure et al. 2015. 11

Prebiotic molecules are abundant in the planetformation regions of protoplanetary disks. Well, duh, but now we can see it: q q Water HCN, CO 2, C 2 H 2 PAHs Ice line: the far-infrared lines of water – which would be most prominent in cooler gas at larger r – are much fainter, and ice emission features are observed. e. g. Carr & Najita 2007, Najita et al. 2013, Sargent et al. 2014, Mc. Clure et al. 2015 12

Dust in disks settles to midplane during the protostellar phase (< 0. 5 Myr). q Range of HCN/H 2 O = range of degree of self-extinction, and thus sedimentation. q Models of spectra demand similar dust settling, suggest continuum spectral indices to measure it. q Degree of sedimentation same for all clusters of Class II objects, 0. 5 -5 Myr: sedimentation complete by then, as long expected theoretically. q Thus it’s no wonder that planets have already formed in the embedded disk of the Class I protostar HL Tau: dust concentration at mid-plane enhances core-accretion processes very early. D’Alessio et al. 2001, 2006; Furlan et al. 2005, 2006, 2008, 2011. 13

Dust in disks settles to midplane during the protostellar phase (< 0. 5 Myr). D’Alessio et al. 2001, 2006; Furlan et al. 2005, 2006, 2008, 2011. 10 -9 νFν (erg sec-1 cm-2) q Range of HCN/H 2 O = range of degree of self-extinction, and thus sedimentation. q Models of spectra demand similar dust settling, suggest continuum spectral indices to measure it. q Degree of sedimentation same for all clusters of Class II objects, 0. 5 -5 Myr: sedimentation complete by then, as long expected theoretically. q Thus it’s no wonder that planets have already formed in the embedded disk of the Class I protostar HL Tau: dust concentration at mid-plane enhances core-accretion processes very early. Models ε=1 Star ε = 0. 1 10 -10 GO Tau ε = 0. 01 ε = 0. 001 5 10 20 50 Wavelength (μm) HST Model 14

Dust in disks settles to midplane during the protostellar phase (< 0. 5 Myr). q Range of HCN/H 2 O = range of degree of self-extinction, and thus sedimentation. q Models of spectra demand similar dust settling, suggest continuum spectral indices to measure it. q Degree of sedimentation same for all clusters of Class II objects, 0. 5 -5 Myr: sedimentation complete by then, as long expected theoretically. q Thus it’s no wonder that planets have already formed in the embedded disk of the Class I protostar HL Tau: dust concentration at mid-plane enhances core-accretion processes very early. D’Alessio et al. 2001, 2006; Furlan et al. 2005, 2006, 2008, 2011. Molecular-line fluxes from Najita et al. 2013; n 13 -31 from Furlan et al. 2011. 15

Dust in disks settles to midplane during the protostellar phase (< 0. 5 Myr). q Range of HCN/H 2 O = range of degree of self-extinction, and thus sedimentation. q Models of spectra demand similar dust settling, suggest continuum spectral indices to measure it. q Degree of sedimentation same for all clusters of Class II objects, 0. 5 -5 Myr: sedimentation complete by then, as long expected theoretically. q Thus it’s no wonder that planets have already formed in the embedded disk of the Class I protostar HL Tau: dust concentration at mid-plane enhances core-accretion processes very early. D’Alessio et al. 2001, 2006; Furlan et al. 2005, 2006, 2008, 2011. Tran sitio n al di sks Radiallycontinuous disks Data: n 13 -31 vs. 10 - m silicate equivalent width for 750 protoplanetary disks in six nearby associations. Contour intervals are linear. Models: ε=1 ε = 0. 01 ε = 0. 001 16

Dust in disks settles to midplane during the protostellar phase (< 0. 5 Myr). q Range of HCN/H 2 O = range of degree of self-extinction, and thus sedimentation. q Models of spectra demand similar dust settling, suggest continuum spectral indices to measure it. q Degree of sedimentation same for all clusters of Class II objects, 0. 5 -5 Myr: sedimentation complete by then, as long expected theoretically. q Thus it’s no wonder that planets have already formed in the embedded disk of the Class I protostar HL Tau: dust concentration at mid-plane enhances coreaccretion processes very early. D’Alessio et al. 2001, 2006; Furlan et al. 2005, 2006, 2008, 2011. HL Tau at 870 m ALMA Early Science Team 2015 17

The crystalline-dust mass fraction of disks increases with age, 0. 7 -5 Myr. q No statistically-significant difference in large-grain mass fractions, among clusters in this age range. q Crystalline component of suspended submicron grains evolves. • Notably silica, which increases from very small numbers to 510% of the crystalline silicates in the outer disk. q Concordance: “high-temperature” silica demands the same formation conditions as chondrules, which in the presolar nebula were produced over the course of 0. 5 -5 Myr (Connelly et al. 2012). Sargent et al. 2006, 2009; Kessler et al 2006; Bouwman et al. 2008; Olofsson et al. 2013; Koch et al. 2015 Ori. A-254 Large warm grains K-S tests D p (%) Taurus-ONC 0. 11 16 Taurus-L 1641 0. 11 80 Koch et al. 2015 18

The crystalline-dust mass fraction of disks increases with age, 0. 7 -5 Myr. q Concordance: “high-temperature” silica demands the same formation conditions as chondrules, which in the presolar nebula were produced over the course of 0. 5 -5 Myr (Connelly et al. 2012). Sargent et al. 2006, 2009; Kessler et al 2006; Bouwman et al. 2008; Olofsson et al. 2013; Koch et al. 2015 Courtesy Dave Joswiak, Don Brownlee, and Graciela Matrajt q No statistically-significant difference in large-grain mass fractions, among clusters in this age range. q Crystalline component of suspended submicron grains evolves. • Notably silica, which increases from very small numbers to 510% of the crystalline silicates in the outer disk. ZZ Tau Sargent et al. 2009 19

The crystalline-dust mass fraction of disks increases with age, 0. 7 -5 Myr. q No statistically-significant difference in large-grain mass fractions, among clusters in this age range. q Crystalline component of suspended submicron grains evolves. • Notably silica, which increases from very small numbers to 510% of the crystalline silicates in the outer disk. q Concordance: “high-temperature” silica demands the same formation conditions as chondrules, which in the presolar nebula were produced over the course of 0. 5 -5 Myr (Connelly et al. 2012). Sargent et al. 2006, 2009; Kessler et al 2006; Bouwman et al. 2008; Olofsson et al. 2013; Koch et al. 2015 Warm enstatite D p (%) Taurus-ONC 0. 52 10 -8 Taurus-L 1641 0. 48 10 -7 D p (%) Taurus-ONC 0. 37 10 -5 Taurus-L 1641 0. 45 10 -6 Cold silica Koch et al. 2015 20