NEAR-INFRARED LINEAR POLARIZATION OF ULTRACOOL DWARFS
نویسندگان
چکیده
منابع مشابه
Observations of Ultracool White Dwarfs
We present new spectroscopic and photometric measurements of the white dwarfs LHS 3250 and WD 0346]246. Along with F351[50, these white dwarfs are the coolest ones known, all with e†ective temperatures below 4000 K. Their membership in the Galactic halo population is discussed, and detailed comparisons of all three objects with new atmosphere models are presented. The new models consider the e†...
متن کاملCool versus Ultracool White Dwarfs
A preliminary BV RIJHK analysis of the white dwarfs SSSPM J2231−7514 and SSSPM J2231−7515 is presented. Although both stars were reported to have Teff < 4000 K, the analysis here indicates Teff ≈ 4250 K for both SSSPM J2231−7514 and SSSPM J2231−7515. Given substantial scientific interest in the coolest extant degenerate stars, it is necessary to distinguish sub 4000 K objects from the bulk of c...
متن کاملSpectroscopic distances of nearby ultracool dwarfs
We present updated results of spectroscopic follow-up observations of a sample of 45 M dwarf candidates identified by Phan-Bao et al. (2003) based on the DENIS photometry and proper motion measurements. Forty one of these are nearby late-M dwarfs (d<30 pc) with spectral types ranging from M5.0 to M8.5 computed from the spectral indices. One contaminant is probably an F-G main sequence star redd...
متن کاملRadio detections of southern ultracool dwarfs
We report the results of a volume-limited survey using the Australia Telescope Compact Array to search for transient and quiescent radio emission from 15 southern hemisphere ultracool dwarfs. We detect radio emission from 2MASSW J0004348–404405 increasing the number of radio loud ultracool dwarfs to 22. We also observe radio emission from 2MASS J10481463–3956062 and 2MASSI J0339352–352544, two ...
متن کاملVolume-limited radio survey of ultracool dwarfs
Aims. We aim to increase the sample of ultracool dwarfs studied in the radio domain to allow a more statistically significant understanding of the physical conditions associated with these magnetically active objects. Methods. We conducted a volume-limited survey at 4.9 GHz of 32 nearby ultracool dwarfs with spectral types covering the range M7 – T8. A statistical analysis was performed on the ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2011
ISSN: 0004-637X,1538-4357
DOI: 10.1088/0004-637x/740/1/4