The Herschel/PACS view of the Cep OB2 region

Global protoplanetary disk evolution and clumpy star formation

Aurora Sicilia-Aguilar (Lead / Corresponding author), Veronica Roccatagliata, Konstantin Getman, Pablo Riviere-Marichalar, Tilman Birnstiel, Bruno Merin, Min Fang, Thomas Henning, Carlos Eiroa, Thayne Currie

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Context. The Cep OB2 region, with its two intermediate-aged clusters Tr 37 and NGC7160, is a paradigm of sequential star formation and an ideal site for studies of protoplanetary disk evolution.
Aims. We use Herschel data to study the protoplanetary disks and the star formation history of the region.
Methods. Herschel/PACS observations at 70 and 160 ?m probe the disk properties (mass, dust sizes, structure) and the evolutionary state of a large number of young stars. Far-IR data also trace the remnant cloud material and small-scale cloud structure.
Results. We detect 95 protoplanetary disks at 70 ?m, 41 at 160 ?m, and obtain upper limits for more than 130 objects. The detection fraction at 70 ?m depends on the spectral type (88% for K4 or earlier stars, 17% for M3 or later stars) and on the disk type (~50% for full and pre-transitional disks, ~35% for transitional disks, no low-excess/depleted disks detected). Non-accreting disks are not detected, suggesting significantly lower masses. Accreting transition and pre-transition disks have systematically higher 70?m excesses than full disks, suggestive of more massive, flared and/or thicker disks. Herschel data also reveal several mini-clusters in Tr 37, which are small, compact structures containing a few young stars surrounded by nebulosity.
Conclusions. Far-IR data are an excellent probe of the evolution of disks that are too faint for sub-millimetre observations. We find a strong link between far-IR emission and accretion, and between the inner and outer disk structure. Herschel confirms the dichotomy between accreting and non-accreting transition disks. Accretion is a powerful measure of global disk evolution: substantial mass depletion and global evolution need to occur to shut down accretion in a protoplanetary disk, even if the disk has inner holes. Disks likely follow different evolutionary paths: low disk masses do not imply opening inner holes, and having inner holes does not require low disk masses. The mini-clusters reveal multi-episodic star formation in Tr 37. The long survival of mini-clusters suggest that they formed from the fragmentation of the same core. Their various morphologies favour different formation/triggering mechanisms acting within the same cluster. The beads-on-a-string structure in one mini-cluster is consistent with gravitational fragmentation or gravitational focusing, acting on very small scales (solar-mass stars in ~0.5 pc filaments). Multi-episodic star formation could also produce evolutionary variations between disks in the same region. Finally, Herschel also unveils what could be the first heavy mass loss episode of the O6.5 star HD206267 in Tr 37.
Original languageEnglish
Article numberA19
Pages (from-to)1-39
Number of pages39
JournalAstronomy and Astrophysics
Volume573
DOIs
Publication statusPublished - 10 Dec 2014

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protoplanetary disks
star formation
accretion
fragmentation
stars
probe
formation mechanism
size structure
dust
late stars
early stars
history
dichotomies
probes

Keywords

  • astro-ph.SR
  • astro-ph.EP
  • Stars: pre-main sequence
  • Protoplanetary disks
  • Stars: formation
  • Open clusters and associations: individual: CepOB2
  • Circumstellar matter
  • Stars: individual: HD 206267

Cite this

Sicilia-Aguilar, Aurora ; Roccatagliata, Veronica ; Getman, Konstantin ; Riviere-Marichalar, Pablo ; Birnstiel, Tilman ; Merin, Bruno ; Fang, Min ; Henning, Thomas ; Eiroa, Carlos ; Currie, Thayne. / The Herschel/PACS view of the Cep OB2 region : Global protoplanetary disk evolution and clumpy star formation. In: Astronomy and Astrophysics. 2014 ; Vol. 573. pp. 1-39.
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abstract = "Context. The Cep OB2 region, with its two intermediate-aged clusters Tr 37 and NGC7160, is a paradigm of sequential star formation and an ideal site for studies of protoplanetary disk evolution.Aims. We use Herschel data to study the protoplanetary disks and the star formation history of the region.Methods. Herschel/PACS observations at 70 and 160 ?m probe the disk properties (mass, dust sizes, structure) and the evolutionary state of a large number of young stars. Far-IR data also trace the remnant cloud material and small-scale cloud structure.Results. We detect 95 protoplanetary disks at 70 ?m, 41 at 160 ?m, and obtain upper limits for more than 130 objects. The detection fraction at 70 ?m depends on the spectral type (88{\%} for K4 or earlier stars, 17{\%} for M3 or later stars) and on the disk type (~50{\%} for full and pre-transitional disks, ~35{\%} for transitional disks, no low-excess/depleted disks detected). Non-accreting disks are not detected, suggesting significantly lower masses. Accreting transition and pre-transition disks have systematically higher 70?m excesses than full disks, suggestive of more massive, flared and/or thicker disks. Herschel data also reveal several mini-clusters in Tr 37, which are small, compact structures containing a few young stars surrounded by nebulosity.Conclusions. Far-IR data are an excellent probe of the evolution of disks that are too faint for sub-millimetre observations. We find a strong link between far-IR emission and accretion, and between the inner and outer disk structure. Herschel confirms the dichotomy between accreting and non-accreting transition disks. Accretion is a powerful measure of global disk evolution: substantial mass depletion and global evolution need to occur to shut down accretion in a protoplanetary disk, even if the disk has inner holes. Disks likely follow different evolutionary paths: low disk masses do not imply opening inner holes, and having inner holes does not require low disk masses. The mini-clusters reveal multi-episodic star formation in Tr 37. The long survival of mini-clusters suggest that they formed from the fragmentation of the same core. Their various morphologies favour different formation/triggering mechanisms acting within the same cluster. The beads-on-a-string structure in one mini-cluster is consistent with gravitational fragmentation or gravitational focusing, acting on very small scales (solar-mass stars in ~0.5 pc filaments). Multi-episodic star formation could also produce evolutionary variations between disks in the same region. Finally, Herschel also unveils what could be the first heavy mass loss episode of the O6.5 star HD206267 in Tr 37.",
keywords = "astro-ph.SR, astro-ph.EP, Stars: pre-main sequence, Protoplanetary disks, Stars: formation, Open clusters and associations: individual: CepOB2, Circumstellar matter, Stars: individual: HD 206267",
author = "Aurora Sicilia-Aguilar and Veronica Roccatagliata and Konstantin Getman and Pablo Riviere-Marichalar and Tilman Birnstiel and Bruno Merin and Min Fang and Thomas Henning and Carlos Eiroa and Thayne Currie",
note = "A.S.A. acknowledges support by the Spanish MICINN/MINECO ?Ram髇 y Cajal? program, grant number RYC-2010-06164. A.S.A. and M.F. acknowledge support by the action ?Proyectos de Investigaci髇 fundamental no orientada?, grant number AYA2012-35008. C.E. is partly supported by Spanish MICINN/MINECO grant AYA2011-26202. V.R. is supported by the DLR grant number 50 OR 1109 and by the Bayerischen Gleichstellungsf鰎derung (BGF). T.B. acknowledges support from NASA Origins of Solar Systems grant NNX12AJ04G. M1 - A19",
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language = "English",
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Sicilia-Aguilar, A, Roccatagliata, V, Getman, K, Riviere-Marichalar, P, Birnstiel, T, Merin, B, Fang, M, Henning, T, Eiroa, C & Currie, T 2014, 'The Herschel/PACS view of the Cep OB2 region: Global protoplanetary disk evolution and clumpy star formation', Astronomy and Astrophysics, vol. 573, A19, pp. 1-39. https://doi.org/10.1051/0004-6361/201424669

The Herschel/PACS view of the Cep OB2 region : Global protoplanetary disk evolution and clumpy star formation. / Sicilia-Aguilar, Aurora (Lead / Corresponding author); Roccatagliata, Veronica; Getman, Konstantin; Riviere-Marichalar, Pablo; Birnstiel, Tilman; Merin, Bruno; Fang, Min; Henning, Thomas; Eiroa, Carlos; Currie, Thayne.

In: Astronomy and Astrophysics, Vol. 573, A19, 10.12.2014, p. 1-39.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The Herschel/PACS view of the Cep OB2 region

T2 - Global protoplanetary disk evolution and clumpy star formation

AU - Sicilia-Aguilar, Aurora

AU - Roccatagliata, Veronica

AU - Getman, Konstantin

AU - Riviere-Marichalar, Pablo

AU - Birnstiel, Tilman

AU - Merin, Bruno

AU - Fang, Min

AU - Henning, Thomas

AU - Eiroa, Carlos

AU - Currie, Thayne

N1 - A.S.A. acknowledges support by the Spanish MICINN/MINECO ?Ram髇 y Cajal? program, grant number RYC-2010-06164. A.S.A. and M.F. acknowledge support by the action ?Proyectos de Investigaci髇 fundamental no orientada?, grant number AYA2012-35008. C.E. is partly supported by Spanish MICINN/MINECO grant AYA2011-26202. V.R. is supported by the DLR grant number 50 OR 1109 and by the Bayerischen Gleichstellungsf鰎derung (BGF). T.B. acknowledges support from NASA Origins of Solar Systems grant NNX12AJ04G. M1 - A19

PY - 2014/12/10

Y1 - 2014/12/10

N2 - Context. The Cep OB2 region, with its two intermediate-aged clusters Tr 37 and NGC7160, is a paradigm of sequential star formation and an ideal site for studies of protoplanetary disk evolution.Aims. We use Herschel data to study the protoplanetary disks and the star formation history of the region.Methods. Herschel/PACS observations at 70 and 160 ?m probe the disk properties (mass, dust sizes, structure) and the evolutionary state of a large number of young stars. Far-IR data also trace the remnant cloud material and small-scale cloud structure.Results. We detect 95 protoplanetary disks at 70 ?m, 41 at 160 ?m, and obtain upper limits for more than 130 objects. The detection fraction at 70 ?m depends on the spectral type (88% for K4 or earlier stars, 17% for M3 or later stars) and on the disk type (~50% for full and pre-transitional disks, ~35% for transitional disks, no low-excess/depleted disks detected). Non-accreting disks are not detected, suggesting significantly lower masses. Accreting transition and pre-transition disks have systematically higher 70?m excesses than full disks, suggestive of more massive, flared and/or thicker disks. Herschel data also reveal several mini-clusters in Tr 37, which are small, compact structures containing a few young stars surrounded by nebulosity.Conclusions. Far-IR data are an excellent probe of the evolution of disks that are too faint for sub-millimetre observations. We find a strong link between far-IR emission and accretion, and between the inner and outer disk structure. Herschel confirms the dichotomy between accreting and non-accreting transition disks. Accretion is a powerful measure of global disk evolution: substantial mass depletion and global evolution need to occur to shut down accretion in a protoplanetary disk, even if the disk has inner holes. Disks likely follow different evolutionary paths: low disk masses do not imply opening inner holes, and having inner holes does not require low disk masses. The mini-clusters reveal multi-episodic star formation in Tr 37. The long survival of mini-clusters suggest that they formed from the fragmentation of the same core. Their various morphologies favour different formation/triggering mechanisms acting within the same cluster. The beads-on-a-string structure in one mini-cluster is consistent with gravitational fragmentation or gravitational focusing, acting on very small scales (solar-mass stars in ~0.5 pc filaments). Multi-episodic star formation could also produce evolutionary variations between disks in the same region. Finally, Herschel also unveils what could be the first heavy mass loss episode of the O6.5 star HD206267 in Tr 37.

AB - Context. The Cep OB2 region, with its two intermediate-aged clusters Tr 37 and NGC7160, is a paradigm of sequential star formation and an ideal site for studies of protoplanetary disk evolution.Aims. We use Herschel data to study the protoplanetary disks and the star formation history of the region.Methods. Herschel/PACS observations at 70 and 160 ?m probe the disk properties (mass, dust sizes, structure) and the evolutionary state of a large number of young stars. Far-IR data also trace the remnant cloud material and small-scale cloud structure.Results. We detect 95 protoplanetary disks at 70 ?m, 41 at 160 ?m, and obtain upper limits for more than 130 objects. The detection fraction at 70 ?m depends on the spectral type (88% for K4 or earlier stars, 17% for M3 or later stars) and on the disk type (~50% for full and pre-transitional disks, ~35% for transitional disks, no low-excess/depleted disks detected). Non-accreting disks are not detected, suggesting significantly lower masses. Accreting transition and pre-transition disks have systematically higher 70?m excesses than full disks, suggestive of more massive, flared and/or thicker disks. Herschel data also reveal several mini-clusters in Tr 37, which are small, compact structures containing a few young stars surrounded by nebulosity.Conclusions. Far-IR data are an excellent probe of the evolution of disks that are too faint for sub-millimetre observations. We find a strong link between far-IR emission and accretion, and between the inner and outer disk structure. Herschel confirms the dichotomy between accreting and non-accreting transition disks. Accretion is a powerful measure of global disk evolution: substantial mass depletion and global evolution need to occur to shut down accretion in a protoplanetary disk, even if the disk has inner holes. Disks likely follow different evolutionary paths: low disk masses do not imply opening inner holes, and having inner holes does not require low disk masses. The mini-clusters reveal multi-episodic star formation in Tr 37. The long survival of mini-clusters suggest that they formed from the fragmentation of the same core. Their various morphologies favour different formation/triggering mechanisms acting within the same cluster. The beads-on-a-string structure in one mini-cluster is consistent with gravitational fragmentation or gravitational focusing, acting on very small scales (solar-mass stars in ~0.5 pc filaments). Multi-episodic star formation could also produce evolutionary variations between disks in the same region. Finally, Herschel also unveils what could be the first heavy mass loss episode of the O6.5 star HD206267 in Tr 37.

KW - astro-ph.SR

KW - astro-ph.EP

KW - Stars: pre-main sequence

KW - Protoplanetary disks

KW - Stars: formation

KW - Open clusters and associations: individual: CepOB2

KW - Circumstellar matter

KW - Stars: individual: HD 206267

U2 - 10.1051/0004-6361/201424669

DO - 10.1051/0004-6361/201424669

M3 - Article

VL - 573

SP - 1

EP - 39

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A19

ER -