The young population of the Chamaeleon II dark cloud
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The young population of the Chamaeleon II dark cloud. / Spezzi, Loredana; Alcalá, Juan M.; Covino, Elvira; Frasca, Antonio; Gandolfi, Davide; Oliveira, Isa; Chapman, Nicholas; Evans, Neal J., II; Huard, Tracy L.; Jørgensen, Jes K.; Merín, Bruno; Stapelfeldt, Karl R.
In: Astrophysical Journal, Vol. 680, No. 2, 20.06.2008, p. 1295-1318.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The young population of the Chamaeleon II dark cloud
AU - Spezzi, Loredana
AU - Alcalá, Juan M.
AU - Covino, Elvira
AU - Frasca, Antonio
AU - Gandolfi, Davide
AU - Oliveira, Isa
AU - Chapman, Nicholas
AU - Evans, Neal J., II
AU - Huard, Tracy L.
AU - Jørgensen, Jes K.
AU - Merín, Bruno
AU - Stapelfeldt, Karl R.
PY - 2008/6/20
Y1 - 2008/6/20
N2 - We discuss the results of the optical spectroscopic follow-up of pre-main-sequence (PMS) objects and candidates selected in the Chamaeleon II dark cloud based on data from the Spitzer Legacy survey "From Molecular Cores to Planet Forming Disks" (c2d) and from previous surveys. Our sample includes both objects with infrared excess selected according to c2d criteria and referred to as young stellar objects and other cloud members and candidates selected from complementary optical and near-infrared data. We characterize the sample of objects by deriving their physical parameters. The vast majority of objects have masses M ≤ 1 M∞ and ages <6 Myr. Several of the PMS objects and candidates lie very close to or below the hydrogen-burning limit. A first estimate of the slope of the initial mass function in Cha II is consistent with that of other T associations. The star formation efficiency in the cloud (1%-4%) is consistent with our own estimates for Taurus and Lupus, but significantly lower than for Cha I. This might mean that different star formation activities in the Chamaeleon clouds may reflect a different history of star formation. We also find that the Cha II cloud is turning some 8 M∞⊙ into stars every megayear, which is less than the star formation rate in the other c2d clouds. However, the star formation rate is not steady and evidence is found that the star formation in Cha II might have occurred very rapidly. The Hα emission of the Cha II PMS objects, as well as possible correlations between their stellar and disk properties, is also investigated.
AB - We discuss the results of the optical spectroscopic follow-up of pre-main-sequence (PMS) objects and candidates selected in the Chamaeleon II dark cloud based on data from the Spitzer Legacy survey "From Molecular Cores to Planet Forming Disks" (c2d) and from previous surveys. Our sample includes both objects with infrared excess selected according to c2d criteria and referred to as young stellar objects and other cloud members and candidates selected from complementary optical and near-infrared data. We characterize the sample of objects by deriving their physical parameters. The vast majority of objects have masses M ≤ 1 M∞ and ages <6 Myr. Several of the PMS objects and candidates lie very close to or below the hydrogen-burning limit. A first estimate of the slope of the initial mass function in Cha II is consistent with that of other T associations. The star formation efficiency in the cloud (1%-4%) is consistent with our own estimates for Taurus and Lupus, but significantly lower than for Cha I. This might mean that different star formation activities in the Chamaeleon clouds may reflect a different history of star formation. We also find that the Cha II cloud is turning some 8 M∞⊙ into stars every megayear, which is less than the star formation rate in the other c2d clouds. However, the star formation rate is not steady and evidence is found that the star formation in Cha II might have occurred very rapidly. The Hα emission of the Cha II PMS objects, as well as possible correlations between their stellar and disk properties, is also investigated.
KW - Circumstellar matter
KW - Infrared: stars
KW - Planetary systems: protoplanetary disks
KW - Stars: formation
KW - Stars: low-mass, brown dwarfs
KW - Stars: pre-main-sequence
UR - http://www.scopus.com/inward/record.url?scp=46249130447&partnerID=8YFLogxK
U2 - 10.1086/587931
DO - 10.1086/587931
M3 - Journal article
AN - SCOPUS:46249130447
VL - 680
SP - 1295
EP - 1318
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
ER -
ID: 229739643