Radio continuum monitoring of the extreme carbon star IRC + 10216
نویسندگان
چکیده
We describe Very Large Array observations of the extreme carbon star IRC+10216 at 8.4, 14.9, and 22.5 GHz made over a two year period. We find possible variability correlated with the infrared phase and a cm-to sub-millimeter wavelength spectral index very close to 2. The variability, observed flux densities, and upper limit on the size are consistent with the emission arising from the stellar photosphere or a slightly larger radio photosphere.
منابع مشابه
ar X iv : a st ro - p h / 03 02 10 3 v 1 5 F eb 2 00 3 Detection of OH Towards the Extreme Carbon Star IRC + 10216
We report the detection of the 1665 and 1667MHz main lines of OH (hydroxyl) and upper limits on the 1612MHz satellite line of OH towards the carbonrich AGB star, IRC+10216. We find a beam averaged fractional abundance x(OH) ∼ 4 × 10. This detection supports the identification by Melnick et al. (2001) of the 110−101 transition of water vapor with a 556.936GHz emission feature detected towards IR...
متن کاملar X iv : a st ro - p h / 04 07 15 3 v 1 7 J ul 2 00 4 Detection of Formaldehyde Towards the Extreme Carbon Star IRC + 10216
We report the detection of H2CO (formaldehyde) around the carbon-rich AGB star, IRC+10216. We find a fractional abundance with respect to molecular hydrogen of x(H2CO) = 1.3 +1.5 −0.8 × 10 . This corresponds to a formaldehyde abundance with respect to water vapor of x(H2CO)/x(H2O) = (1.1±0.2)×10 , in line with the formaldehyde abundances found in Solar System comets, and indicates that the puta...
متن کاملA molecular line survey of the extreme carbon star CRL3068 at millimeter wavelengths
We present the results of a molecular line survey of the extreme carbon star CRL3068. The observations were carried out with the Arizona Radio Observatory (ARO) 12m telescope and the Heinrich Hertz Submillimeter Telescope (SMT) at the λ 2mm and λ 1.3mm atmospheric windows. The observations cover the frequency bands from 130–162GHz and 219.5–267.5GHz. The typical sensitivities achieved are TR < ...
متن کاملMulti-wavelength diffraction-limited imaging of the evolved carbon star IRC+10216, II
High angular resolution images of IRC+10216 taken at various bandpasses within the nearinfrared h, k & l bands are presented. The maps have the highest angular resolution yet recovered, and were reconstructed from interferometric measurements obtained at the Keck 1 telescope in 1997 December and 1998 April, forming a subset of a 7-epoch monitoring program presented earlier (Tuthill, Monnier, Da...
متن کاملThe abundance of S in IRC+10216 and its production in the Galaxy
The J = 2 − 1 and 3 − 2 rotational lines of the rare isotopomer CS and the J = 5 − 4 and 6 − 5 transitions of SiS were detected in the carbon star IRC+10216 (CWLeo). These are the first detections of S bearing molecules in a star and the first spectroscopic detection of SiS. From a comparison of S and S bearing isotopomers, the S/S isotopic ratio is 107(±15). This value is comparable to values ...
متن کامل