The initial mass function in the Taurus star-forming region

César Briceño, Kevin Luhman, Lee Hartmann, John R. Stauffer, J. Davy Kirkpatrick

Research output: Contribution to journalReview article

251 Citations (Scopus)

Abstract

By combining a deep optical imaging (I, z′) survey of 8 deg 2 in the Taurus star-forming region with data from the Two-Micron All-Sky Survey (2MASS) and follow-up spectroscopy, we have performed a search for low-mass Taurus members that is complete to 0.02 M for reddenings of Av ≲ 4. We report the discovery of nine new members with spectral types of M5.75-M9.5, corresponding to masses of 0.1-0.015 M by recent evolutionary models. The new M9.5 member is the least massive brown dwarf found to date in the Taurus star-forming region. We derive an initial mass function (IMF) for the fields surveyed in this work and in our previous studies, which encompass 54% of the known Taurus membership. We compare the Taurus IMF with a similarly derived one for the Trapezium Cluster and to mass functions for the M35 and Pleiades open clusters. While the IMFs in all of these regions flatten near ∼0.8 M, the mass function in Taurus is more narrow and sharply peaked at this mass. Our survey indicates that Taurus has ∼2 × fewer brown dwarfs at 0.020.08 M than the Trapezium. We discuss the implications of these results for theories of the IMF, and suggest that the lower frequency of brown dwarfs in Taurus relative to the Trapezium may result from the low-density star-forming environment, leading to larger minimum Jeans masses.

Original languageEnglish (US)
Pages (from-to)317-335
Number of pages19
JournalAstrophysical Journal
Volume580
Issue number1 I
DOIs
StatePublished - Nov 20 2002

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stars
open clusters
IMF
spectroscopy
low frequencies

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Briceño, C., Luhman, K., Hartmann, L., Stauffer, J. R., & Kirkpatrick, J. D. (2002). The initial mass function in the Taurus star-forming region. Astrophysical Journal, 580(1 I), 317-335. https://doi.org/10.1086/343127
Briceño, César ; Luhman, Kevin ; Hartmann, Lee ; Stauffer, John R. ; Kirkpatrick, J. Davy. / The initial mass function in the Taurus star-forming region. In: Astrophysical Journal. 2002 ; Vol. 580, No. 1 I. pp. 317-335.
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Briceño, C, Luhman, K, Hartmann, L, Stauffer, JR & Kirkpatrick, JD 2002, 'The initial mass function in the Taurus star-forming region', Astrophysical Journal, vol. 580, no. 1 I, pp. 317-335. https://doi.org/10.1086/343127

The initial mass function in the Taurus star-forming region. / Briceño, César; Luhman, Kevin; Hartmann, Lee; Stauffer, John R.; Kirkpatrick, J. Davy.

In: Astrophysical Journal, Vol. 580, No. 1 I, 20.11.2002, p. 317-335.

Research output: Contribution to journalReview article

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AU - Briceño, César

AU - Luhman, Kevin

AU - Hartmann, Lee

AU - Stauffer, John R.

AU - Kirkpatrick, J. Davy

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N2 - By combining a deep optical imaging (I, z′) survey of 8 deg 2 in the Taurus star-forming region with data from the Two-Micron All-Sky Survey (2MASS) and follow-up spectroscopy, we have performed a search for low-mass Taurus members that is complete to 0.02 M⊙ for reddenings of Av ≲ 4. We report the discovery of nine new members with spectral types of M5.75-M9.5, corresponding to masses of 0.1-0.015 M⊙ by recent evolutionary models. The new M9.5 member is the least massive brown dwarf found to date in the Taurus star-forming region. We derive an initial mass function (IMF) for the fields surveyed in this work and in our previous studies, which encompass 54% of the known Taurus membership. We compare the Taurus IMF with a similarly derived one for the Trapezium Cluster and to mass functions for the M35 and Pleiades open clusters. While the IMFs in all of these regions flatten near ∼0.8 M⊙, the mass function in Taurus is more narrow and sharply peaked at this mass. Our survey indicates that Taurus has ∼2 × fewer brown dwarfs at 0.020.08 M ⊙ than the Trapezium. We discuss the implications of these results for theories of the IMF, and suggest that the lower frequency of brown dwarfs in Taurus relative to the Trapezium may result from the low-density star-forming environment, leading to larger minimum Jeans masses.

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Briceño C, Luhman K, Hartmann L, Stauffer JR, Kirkpatrick JD. The initial mass function in the Taurus star-forming region. Astrophysical Journal. 2002 Nov 20;580(1 I):317-335. https://doi.org/10.1086/343127