ﻻ يوجد ملخص باللغة العربية
Using the Infrared Array Camera and the Multiband Imaging Photometer aboard the {it Spitzer Space Telescope}, we have obtained images of the Lupus 3 star-forming cloud at 3.6, 4.5, 5.8, 8.0, and 24 micron. We present photometry in these bands for the 41 previously known members that are within our images. In addition, we have identified 19 possible new members of the cloud based on red 3.6-8.0 micron colors that are indicative of circumstellar disks. We have performed optical spectroscopy on 6 of these candidates, all of which are confirmed as young low-mass members of Lupus 3. The spectral types of these new members range from M4.75 to M8, corresponding to masses of 0.2-0.03 $M_odot$ for ages of $sim1$ Myr according to theoretical evolutionary models. We also present optical spectroscopy of a candidate disk-bearing object in the vicinity of the Lupus 1 cloud, 2M 1541-3345, which Jayawardhana & Ivanov recently classified as a young brown dwarf ($Msim0.03$ $M_odot$) with a spectral type of M8. In contrast to their results, we measure an earlier spectral type of M5.75$pm$0.25 for this object, indicating that it is probably a low-mass star ($Msim0.1$ $M_odot$). In fact, according to its gravity-sensitive absorption lines and its luminosity, 2M 1541-3345 is older than members of the Lupus clouds ($tausim1$ Myr) and instead is probably a more evolved pre-main-sequence star that is not directly related to the current generation of star formation in Lupus.
We present new 890 $mu m$ continuum ALMA observations of 5 brown dwarfs (BDs) with infrared excess in Lupus I and III -- which, in combination with 4 BDs previously observed, allowed us to study the mm properties of the full known BD disk population
We report the complete photometric results from our Herschel study which is the first comprehensive program to search for far-infrared emission from cold dust around young brown dwarfs. We surveyed 50 fields containing 51 known or suspected brown dwa
We report the discovery of an esdL3 subdwarf, ULAS J020858.62+020657.0, and a usdL4.5 subdwarf, ULAS J230711.01+014447.1. They were identified as L subdwarfs by optical spectra obtained with the Gran Telescopio Canarias, and followed up by optical-to
There is growing observational evidence that disk evolution is stellar-mass dependent. Here, we show that these dependencies extend to the atomic and molecular content of disk atmospheres. We analyze a unique dataset of high-resolution Spitzer/IRS sp
Precise measurements of the fundamental properties of low-mass stars and brown dwarfs are key to understanding the physics underlying their formation and evolution. While there has been great progress over the last decade in studying the bulk spectro