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Meeting the Cool Neighbors. V. A 2MASS-Selected Sample of Ultracool Dwarfs
We present the initial results of our effort to create a statisticallyrobust, volume-limited sample of ultracool dwarfs from the Two MicronAll Sky Survey Second Incremental Data Release. We are engaged in amultifaceted search for nearby late-type objects, and this is the firstinstallment of our search using purely photometric selection. The goalof this work is a determination of the low-mass star and brown dwarfluminosity function in the infrared. Here we outline the construction ofthe sample, dubbed 2MU2, and present our first results, including thediscovery of 186 M7-L6 dwarfs-47 of which are likely to be within 20 pcof the Sun. These results represent 66% of the ultracool candidates inour sample yet constitute a 127% increase in the number of ultracooldwarfs known within the volume searched (covering 40% of the sky out to20 pc). In addition, we have identified 10 M4-M6.5 objects that arelikely to be within 20 pc (or within 1 σ). Finally, based on theseinitial data, we present a preliminary luminosity function and discussseveral interesting features of the partial sample presented here. Onceour sample is complete, we will use our measured luminosity function toconstrain the mass function of low-mass stars and brown dwarfs.
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| Takýmyýldýz: | Ejderha |
| Sað Açýklýk: | 17h36m09.22s |
| Yükselim: | +52°28'59.5" |
| Görünürdeki Parlaklýk: | 8.39 |
| Uzaklýk: | 1449.275 parsek |
| özdevim Sað Açýklýk: | 3.9 |
| özdevim Yükselim: | -19 |
| B-T magnitude: | 10.526 |
| V-T magnitude: | 8.567 |
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