ALMA Observations of Circumstellar Disks in the Upper Scorpius OB Association

Transcription

1 ALMA Observations of Circumstellar Disks in the Upper Scorpius OB Association Based on Barenfeld et al. (2016) Image Credit: ESO/L. Calçada Scott Barenfeld (Caltech) with John Carpenter, Luca Ricci, and Andrea Isella

2 Outline 1

3 Disk Frequency (%) Upper Sco: the end of primordial disk evolution Age (Myr) Hernandez et al. (2008) 2

4 Disk Frequency (%) Upper Sco: the end of primordial disk evolution Upper Sco (age = 5-11 Myr, d = 145 pc) Age (Myr) Hernandez et al. (2008) 2

5 Upper Sco Disk Sample 3

6 Our ALMA Upper Sco Survey 106 disks in Upper Sco (Luhman & Mamajek 2012) 341 GHz (0.88 mm) continuum and CO J = 3-2 4

7 Our ALMA Upper Sco Survey 106 disks in Upper Sco (Luhman & Mamajek 2012) 341 GHz (0.88 mm) continuum and CO J = resolution 0.15 mjy continuum sensitivity 4

8 Our ALMA Upper Sco Survey 106 disks in Upper Sco (Luhman & Mamajek 2012) 341 GHz (0.88 mm) continuum and CO J = resolution 0.15 mjy continuum sensitivity 50 AU resolution 0.1 M of dust 4

9 Our ALMA Upper Sco Survey 106 disks in Upper Sco (Luhman & Mamajek 2012) 341 GHz (0.88 mm) continuum and CO J = resolution 0.15 mjy continuum sensitivity 50 AU resolution 0.1 M of dust Disk Type Continuum CO Primordial 53/75 26/75 Debris/Evolved Transitional Detections 5/31 0/31 4

10 0.88 mm continuum images, 0.34 resolution 5

11 Disk fluxes are correlated with spectral type. 6

12 Faint continuum disks are also faint in CO. 7

13 Faint continuum disks are also faint in CO. 7

14 Faint continuum disks are also faint in CO. < 40 AU or depleted 7

15 Conversion of continuum flux density to dust mass M dust = S νd 2 κ ν B ν (T) 8

16 Conversion of continuum flux density to dust mass 145 pc M dust = S νd 2 κ ν B ν (T) 8

17 Conversion of continuum flux density to dust mass 145 pc M dust = S νd 2 κ ν B ν (T) κ 341 GHz = 2.7 cm 2 /g 8

18 Conversion of continuum flux density to dust mass 145 pc M dust = S νd 2 κ ν B ν (T) κ 341 GHz = 2.7 cm 2 /g T dust = 25 K L L Sun

19 Dust mass correlates with stellar mass. 9

20 Dust mass to stellar mass ratio declines with age. 10

21 Dust mass to stellar mass ratio declines with age. 10

22 Dust mass to stellar mass ratio declines with age. Lupus Data: Ansdell et al. (2016), Alcalá et al. (2014, 2016) Taurus Data: Andrews et al. (2013) Upper Sco Data: Barenfeld et al. (2016) 10

23 Dust mass to stellar mass ratio declines with age. 11

24 Dust mass to stellar mass ratio declines with age. 5 11

25 Dust Mass Evolution Summary Disk dust mass is correlated with stellar mass in Upper Sco, consistent with younger systems. 12

26 Dust Mass Evolution Summary Disk dust mass is correlated with stellar mass in Upper Sco, consistent with younger systems. BUT, the ratio of disk dust mass to stellar mass is lower in Upper Sco than in Taurus and Lupus by a factor of 5. 12

27 Dust Mass Evolution Summary Disk dust mass is correlated with stellar mass in Upper Sco, consistent with younger systems. BUT, the ratio of disk dust mass to stellar mass is lower in Upper Sco than in Taurus and Lupus by a factor of 5. Disk dissipation? Grain growth? Planet formation? 12

28 Dust Mass Evolution Summary Disk dust mass is correlated with stellar mass in Upper Sco, consistent with younger systems. BUT, the ratio of disk dust mass to stellar mass is lower in Upper Sco than in Taurus and Lupus by a factor of 5. Disk dissipation? Grain growth? Planet formation? See Barenfeld et al. (2016) for more details. 12