TY - JOUR

T1 - The Spitzer c2d survey of large, nearby, interstellar clouds. XI. Lupus observed with IRAC and MIPS

AU - Merín, Bruno

AU - Jørgensen, Jes

AU - Spezzi, Loredana

AU - Alcalá, Juan M.

AU - Evans, Neal J., II

AU - Harvey, Paul M.

AU - Prusti, Timo

AU - Chapman, Nicholas

AU - Huard, Tracy

AU - Van Dishoeck, Ewine F.

AU - Comerón, Fernando

PY - 2008/8/1

Y1 - 2008/8/1

N2 - We present c2d Spitzer IRAC observations of the Lupus I, III, and IV dark clouds and discuss them in combination with optical, near-infrared, and c2d MIPS data. With the Spitzer data, the new sample contains 159 stars, 4 times larger than the previous one. It is dominated by low- and very low mass stars, and it is complete down to M ≈ 0.1 M⊙. We find 30%-40% binaries with separations between 100 and 2000 AU with no apparent effect on the disk properties of the members. A large majority of the objects are Class II or III objects, with only 20 (12%) Class I or flat-spectrum sources. The disk sample is complete down to "debris"-like systems in stars as small as M ≈ 0.2 M⊙ and includes substellar objects with larger IR excesses. The disk fraction in Lupus is 70%-80%, consistent with an age of 1-2 Myr. However, the young population contains 20% optically thick accretion disks and 40% relatively less flared disks. A growing variety of inner disk structures is found for larger inner disk clearings for equal disk masses. Lupus III is the most centrally populated and rich, followed by Lupus I with a filamentary structure and by Lupus IV, where a very high density core with little star formation activity has been found. We estimate star formation rates in Lupus of 2-10 M⊙ Myr-1 and star formation efficiencies of a few percent, apparently correlated with the associated cloud masses.

AB - We present c2d Spitzer IRAC observations of the Lupus I, III, and IV dark clouds and discuss them in combination with optical, near-infrared, and c2d MIPS data. With the Spitzer data, the new sample contains 159 stars, 4 times larger than the previous one. It is dominated by low- and very low mass stars, and it is complete down to M ≈ 0.1 M⊙. We find 30%-40% binaries with separations between 100 and 2000 AU with no apparent effect on the disk properties of the members. A large majority of the objects are Class II or III objects, with only 20 (12%) Class I or flat-spectrum sources. The disk sample is complete down to "debris"-like systems in stars as small as M ≈ 0.2 M⊙ and includes substellar objects with larger IR excesses. The disk fraction in Lupus is 70%-80%, consistent with an age of 1-2 Myr. However, the young population contains 20% optically thick accretion disks and 40% relatively less flared disks. A growing variety of inner disk structures is found for larger inner disk clearings for equal disk masses. Lupus III is the most centrally populated and rich, followed by Lupus I with a filamentary structure and by Lupus IV, where a very high density core with little star formation activity has been found. We estimate star formation rates in Lupus of 2-10 M⊙ Myr-1 and star formation efficiencies of a few percent, apparently correlated with the associated cloud masses.

KW - Infrared: general

KW - ISM: individual (Lupus I, Lupus III, Lupus IV)

KW - Stars: formation

KW - Stars: pre-main-sequence

UR - http://www.scopus.com/inward/record.url?scp=49449094127&partnerID=8YFLogxK

U2 - 10.1086/588042

DO - 10.1086/588042

M3 - Journal article

AN - SCOPUS:49449094127

VL - 177

SP - 551

EP - 583

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

ER -