Astrophys. J., 785, 159 (2014/April-3)
Substellar objects in nearby young clusters (SONYC). VIII. Substellar population in Lupus 3.
MUZIC K., SCHOLZ A., GEERS V.C., JAYAWARDHANA R. and LOPEZ MARTI B.
Abstract (from CDS):
SONYC–Substellar Objects in Nearby Young Clusters–is a survey program to investigate the frequency and properties of substellar objects in nearby star-forming regions. We present a new imaging and spectroscopic survey conducted in the young (∼1 Myr), nearby (∼200 pc) star-forming region Lupus 3. Deep optical and near-infrared images were obtained with MOSAIC-II and NEWFIRM at the CTIO 4 m telescope, covering ∼1.4 deg2 on the sky. The i-band completeness limit of 20.3 mag is equivalent to 0.009-0.02 M☉, for AV ≤ 5. Photometry and 11-12 yr baseline proper motions were used to select candidate low-mass members of Lupus 3. We performed a spectroscopic follow-up of 123 candidates, using VIMOS at the Very Large Telescope, and we identify 7 probable members, among which 4 have spectral type later than M6.0 and Teff ≤ 3000 K, i.e., are probably substellar in nature. Two of the new probable members of Lupus 3 appear underluminous for their spectral class and exhibit emission line spectrum with strong Hα or forbidden lines associated with active accretion. We derive a relation between the spectral type and effective temperature: Teff= (4120±175) - (172±26)xSpT, where SpT refers to the M spectral subtype between 1 and 9. Combining our results with the previous works on Lupus 3, we show that the spectral type distribution is consistent with that in other star-forming regions, as well as the derived star-to-brown dwarf ratio of 2.0-3.3. We compile a census of all spectroscopically confirmed low-mass members with spectral type M0 or later.
brown dwarfs - stars: formation - stars: low-mass - stars: luminosity function, mass function
VizieR on-line data:
<Available at CDS (J/ApJ/785/159): table2.dat table3.dat table4.dat>
Table 2: SONYC Lup3-NN (Nos 1-27).
View the reference in ADS
To bookmark this query, right click on this link: simbad:2014ApJ...785..159M and select 'bookmark this link' or equivalent in the popup menu