The DOI matches its Crossref record; 33 of the 33 references it cites were found in a registry or an index.
New Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence
Open accessAbstract
We have combined 2MASS and POSS II data in a search for nearby ultracool (later than M6.5) dwarfs with K s < 12. Spectroscopic follow-up observations identify 53 M7–M9.5 dwarfs and seven L dwarfs. The observed space density is 0.0045 ± 0.0008 M8–M9.5 dwarfs per cubic parsec, without accounting for biases, consistent with a mass function that is smooth across the stellar/substellar limit. We show the observed frequency of Hα emission peaks at ∼100% for M7 dwarfs and then decreases for cooler dwarfs. In absolute terms, however, as measured by the ratio of Hα to bolometric luminosity, none of the ultracool M dwarfs can be considered very active compared to earlier M dwarfs, and we show that the decrease that begins at spectral type M6 continues to the latest L dwarfs. We find that flaring is common among the coolest M dwarfs and estimate the frequency of flares at 7% or higher. We show that the kinematics of relatively active (EW > 6 Å) ultracool M dwarfs are consistent with an ordinary old disk stellar population, while the kinematics of inactive ultracool M dwarfs are more typical of a 0.5 Gyr old population. The early L dwarfs in the sample have kinematics consistent with old ages, suggesting that the hydrogen-burning limit is near spectral types L2–L4. We use the available data on M and L dwarfs to show that chromospheric activity drops with decreasing mass and temperature and that at a given (M8 or later) spectral type, the younger field (brown) dwarfs are less active than many of the older, more massive field stellar dwarfs. Thus, contrary to the well-known stellar age-activity relationship, low activity in field ultracool dwarfs can be an indication of comparative youth and substellar mass.
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Cites
The Keck Low-Resolution Imaging Spectrometer
Oke, J. B., Cohen, J. G., Carr, M., Cromer, J., Dingizian, A., Harris, F. H., Labrecque, S., Lucinio, R., Schaal, W., Epps, H., et al. (1995) · Publications of the Astronomical Society of the Pacific · doi:10.1086/133562 · Cited by 2,099
The distribution of low-mass stars in the Galactic disc
Kroupa, P., Tout, C. A., & Gilmore, G. (1993) · Monthly Notices of the Royal Astronomical Society · doi:10.1093/mnras/262.3.545 · Cited by 1,699
Space Distribution and Luminosity Functions of Quasi-Stellar Radio Sources
Schmidt, M. (1968) · The Astrophysical Journal · doi:10.1086/149446 · Cited by 1,561
A Nongray Theory of Extrasolar Giant Planets and Brown Dwarfs
Burrows, A., Marley, M., Hubbard, W. B., Lunine, J. I., Guillot, T., Saumon, D., Freedman, R., Sudarsky, D., & Sharp, C. (1997) · The Astrophysical Journal · doi:10.1086/305002 · Cited by 1,390
Kirkpatrick, J. D., Reid, I. N., Liebert, J., Cutri, R. M., Nelson, B., Beichman, C. A., Dahn, C. C., Monet, D. G., Gizis, J. E., & Skrutskie, M. F. (1999) · The Astrophysical Journal · doi:10.1086/307414 · Cited by 992
Self-citation2MASS Extended Source Catalog: Overview and Algorithms
Jarrett, T. H., Chester, T., Cutri, R., Schneider, S., Skrutskie, M., & Huchra, J. P. (2000) · The Astronomical Journal · doi:10.1086/301330 · Cited by 992
Reid, I. N., Hawley, S. L., & Gizis, J. E. (1995) · The Astronomical Journal · doi:10.1086/117655 · Cited by 664
Self-citationInfrared colors of low-mass stars
Leggett, S. K. (1992) · The Astrophysical Journal Supplement Series · doi:10.1086/191720 · Cited by 635
A standard stellar spectral sequence in the red/near-infrared - Classes K5 to M9
Kirkpatrick, J. D., Henry, T. J., & McCarthy, D. W., Jr. (1991) · The Astrophysical Journal Supplement Series · doi:10.1086/191611 · Cited by 584
Self-citationHawley, S. L., Gizis, J. E., & Reid, I. N. (1996) · The Astronomical Journal · doi:10.1086/118222 · Cited by 498
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Cited by
Galactic Stellar and Substellar Initial Mass Function
Chabrier, G. (2003) · Publications of the Astronomical Society of the Pacific · doi:10.1086/376392 · Cited by 9,071
The Initial Mass Function in the Taurus Star‐forming Region
Briceno, C., Luhman, K. L., Hartmann, L., Stauffer, J. R., & Kirkpatrick, J. D. (2002) · The Astrophysical Journal · doi:10.1086/343127 · Cited by 373
Self-citationA Reappraisal of The Habitability of Planets around M Dwarf Stars
Tarter, J. C., Backus, P. R., Mancinelli, R. L., Aurnou, J. M., Backman, D. E., Basri, G. S., Boss, A. P., Clarke, A., Deming, D., Doyle, L. R., et al. (2007) · Astrobiology · doi:10.1089/ast.2006.0124 · Cited by 340
Self-citationThe habitability of planets orbiting M-dwarf stars
Shields, A. L., Ballard, S., & Johnson, J. A. (2016) · Physics Reports · doi:10.1016/j.physrep.2016.10.003 · Cited by 319
MEETING THE COOL NEIGHBORS. X. ULTRACOOL DWARFS FROM THE 2MASS ALL-SKY DATA RELEASE
Neill Reid, I., Cruz, K. L., Kirkpatrick, J. D., Allen, P. R., Mungall, F., Liebert, J., Lowrance, P., & Sweet, A. (2008) · The Astronomical Journal · doi:10.1088/0004-6256/136/3/1290 · Cited by 257
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Metadata
- Authors
- Gizis, J. E., Monet, D. G., Reid, I. N., Kirkpatrick, J. D., Liebert, J., & Williams, R. J.
- Venue
- The Astronomical Journal
- Publisher
- American Astronomical Society
- Published
- 2000-08
- Volume
- 120
- Issue
- 2
- Pages
- 1085-1099
- ISSN
- 0004-6256 (ISSN-L)
- OpenAlex
- W1997087322
- Cited by
- 503
- References
- 33
- FWCI
- 28.65
- Type
- journal article
- Language
- en
- Open access
- bronze
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