منابع مشابه
Meeting the Cool New Neighbors V: A 2MASS-Selected Sample of Ultracool Dwarfs
We present initial results of our effort to create a statistically robust, volume-limited sample of ultracool dwarfs from the 2MASS Second Incremental Data Release. We are engaged in a multifaceted search for nearby late-type dwarfs and this is the first installment of our search using purely photometric selection. The goal of this work is a determination of the low-mass star and brown dwarf lu...
متن کاملNew Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence
We have combined 2MASS and POSS II data in a search for nearby ultracool (later than M6.5) dwarfs with Ks < 12. Spectroscopic follow-up observations identify 53 M7 to 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 s...
متن کاملThe widest ultracool binary
Aims. I test the ejection scenario of formation of brown dwarfs and very low-mass stars through the detection of a very wide ultracool binary. Methods. LEHPM 494 (M6.0 ± 1.0 V) and DENIS-P J0021.0–4244 (M9.5 ± 0.5 V) are separated by 1.3 arcmin and are high proper motion co-moving ultracool stars. I have used six astrometric epochs spaced 22 years to confirm their common tangential velocity. Re...
متن کاملPeriodic Bursts of Coherent Radio Emission from an Ultracool Dwarf
We report the detection of periodic (p = 1.96 hours) bursts of extremely bright, 100% circularly polarized, coherent radio emission from the M9 dwarf TVLM 513-46546. Simultaneous photometric monitoring observations have established this periodicity to be the rotation period of the dwarf. These bursts, which were not present in previous observations of this target, confirm that ultracool dwarfs ...
متن کاملEffective temperature scale and bolometric corrections from 2MASS photometry
This paper presents a method to determine effective temperatures, angular semi-diameters and bolometric corrections for population I and II FGK type stars based on V and 2MASS IR photometry. Accurate calibration is accomplished by using a sample of solar analogues, whose average temperature is assumed to be equal to the solar effective temperature of 5777 K. By taking into account all possible ...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 2003
ISSN: 0074-1809
DOI: 10.1017/s0074180900210589