On the MBM 12 young association

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

I present a comprehensive study of the MBM 12 young association (MBM 12A). By combining infrared (IR) photometry from the Two-Micron All-Sky Survey (2MASS) survey with new optical imaging and spectroscopy, I have performed a census of the MBM Ï2A membership that is complete to 0.03 M⊙ (H ∼ 15) for a 1°.75 × 1°.4 field encompassing the MBM 12 cloud. I find five new members with masses of 0.1-0.4 M⊙ and a few additional candidates that have not been observed spectroscopically. From an analysis of optical and IR photometry for stars in the direction of MBM 12, I identify M dwarfs in the foreground and background of the cloud. By comparing the magnitudes of these stars to those of local field dwarfs, I arrive at a distance modulus 7.2 ± 0.5 (275 pc) to the MBM 12 cloud; it is not the nearest molecular cloud and is not inside the local bubble of hot ionized gas as had been implied by previous distance estimates of 50-100 pc. I have also used Li strengths and H-R diagrams to constrain the absolute and relative ages of MBM 12A and other young populations; these data indicate ages of 2+3-1 Myr for MBM 12A and ∼10 Myr for the TW Hya and η Cha associations. MBM 12A may be a slightly evolved version of the aggregates of young stars within the Taurus dark clouds ( ∼1 Myr) near the age of the IC 348 cluster (∼2 Myr).

Original languageEnglish (US)
Pages (from-to)287-306
Number of pages20
JournalAstrophysical Journal
Volume560
Issue number1 PART 1
DOIs
StatePublished - Oct 10 2001

Fingerprint

infrared photometry
stars
census
ionized gases
high temperature gases
molecular clouds
young population
bubbles
diagrams
bubble
diagram
spectroscopy
young
estimates
gas

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Luhman, K. L. / On the MBM 12 young association. In: Astrophysical Journal. 2001 ; Vol. 560, No. 1 PART 1. pp. 287-306.
@article{c41e7a4778ee4c69985e6b627c2b2087,
title = "On the MBM 12 young association",
abstract = "I present a comprehensive study of the MBM 12 young association (MBM 12A). By combining infrared (IR) photometry from the Two-Micron All-Sky Survey (2MASS) survey with new optical imaging and spectroscopy, I have performed a census of the MBM {\"I}2A membership that is complete to 0.03 M⊙ (H ∼ 15) for a 1°.75 × 1°.4 field encompassing the MBM 12 cloud. I find five new members with masses of 0.1-0.4 M⊙ and a few additional candidates that have not been observed spectroscopically. From an analysis of optical and IR photometry for stars in the direction of MBM 12, I identify M dwarfs in the foreground and background of the cloud. By comparing the magnitudes of these stars to those of local field dwarfs, I arrive at a distance modulus 7.2 ± 0.5 (275 pc) to the MBM 12 cloud; it is not the nearest molecular cloud and is not inside the local bubble of hot ionized gas as had been implied by previous distance estimates of 50-100 pc. I have also used Li strengths and H-R diagrams to constrain the absolute and relative ages of MBM 12A and other young populations; these data indicate ages of 2+3-1 Myr for MBM 12A and ∼10 Myr for the TW Hya and η Cha associations. MBM 12A may be a slightly evolved version of the aggregates of young stars within the Taurus dark clouds ( ∼1 Myr) near the age of the IC 348 cluster (∼2 Myr).",
author = "Luhman, {K. L.}",
year = "2001",
month = "10",
day = "10",
doi = "10.1086/322386",
language = "English (US)",
volume = "560",
pages = "287--306",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1 PART 1",

}

On the MBM 12 young association. / Luhman, K. L.

In: Astrophysical Journal, Vol. 560, No. 1 PART 1, 10.10.2001, p. 287-306.

Research output: Contribution to journalArticle

TY - JOUR

T1 - On the MBM 12 young association

AU - Luhman, K. L.

PY - 2001/10/10

Y1 - 2001/10/10

N2 - I present a comprehensive study of the MBM 12 young association (MBM 12A). By combining infrared (IR) photometry from the Two-Micron All-Sky Survey (2MASS) survey with new optical imaging and spectroscopy, I have performed a census of the MBM Ï2A membership that is complete to 0.03 M⊙ (H ∼ 15) for a 1°.75 × 1°.4 field encompassing the MBM 12 cloud. I find five new members with masses of 0.1-0.4 M⊙ and a few additional candidates that have not been observed spectroscopically. From an analysis of optical and IR photometry for stars in the direction of MBM 12, I identify M dwarfs in the foreground and background of the cloud. By comparing the magnitudes of these stars to those of local field dwarfs, I arrive at a distance modulus 7.2 ± 0.5 (275 pc) to the MBM 12 cloud; it is not the nearest molecular cloud and is not inside the local bubble of hot ionized gas as had been implied by previous distance estimates of 50-100 pc. I have also used Li strengths and H-R diagrams to constrain the absolute and relative ages of MBM 12A and other young populations; these data indicate ages of 2+3-1 Myr for MBM 12A and ∼10 Myr for the TW Hya and η Cha associations. MBM 12A may be a slightly evolved version of the aggregates of young stars within the Taurus dark clouds ( ∼1 Myr) near the age of the IC 348 cluster (∼2 Myr).

AB - I present a comprehensive study of the MBM 12 young association (MBM 12A). By combining infrared (IR) photometry from the Two-Micron All-Sky Survey (2MASS) survey with new optical imaging and spectroscopy, I have performed a census of the MBM Ï2A membership that is complete to 0.03 M⊙ (H ∼ 15) for a 1°.75 × 1°.4 field encompassing the MBM 12 cloud. I find five new members with masses of 0.1-0.4 M⊙ and a few additional candidates that have not been observed spectroscopically. From an analysis of optical and IR photometry for stars in the direction of MBM 12, I identify M dwarfs in the foreground and background of the cloud. By comparing the magnitudes of these stars to those of local field dwarfs, I arrive at a distance modulus 7.2 ± 0.5 (275 pc) to the MBM 12 cloud; it is not the nearest molecular cloud and is not inside the local bubble of hot ionized gas as had been implied by previous distance estimates of 50-100 pc. I have also used Li strengths and H-R diagrams to constrain the absolute and relative ages of MBM 12A and other young populations; these data indicate ages of 2+3-1 Myr for MBM 12A and ∼10 Myr for the TW Hya and η Cha associations. MBM 12A may be a slightly evolved version of the aggregates of young stars within the Taurus dark clouds ( ∼1 Myr) near the age of the IC 348 cluster (∼2 Myr).

UR - http://www.scopus.com/inward/record.url?scp=0035841108&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035841108&partnerID=8YFLogxK

U2 - 10.1086/322386

DO - 10.1086/322386

M3 - Article

AN - SCOPUS:0035841108

VL - 560

SP - 287

EP - 306

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART 1

ER -