Journal
ASTROPHYSICAL JOURNAL
Volume 830, Issue 2, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.3847/0004-637X/830/2/159
Keywords
stars: abundances; stars: low-mass
Categories
Funding
- Grants-in-Aid for Scientific Research [14J07824] Funding Source: KAKEN
Ask authors/readers for more resources
It has been suggested that high C/O ratios (>0.8) in circumstellar disks lead to the formation of carbon-dominated planets. Based on the expectation that elemental abundances in the stellar photospheres give the initial abundances in the circumstellar disks, the frequency distributions of C/O ratios of solar-type stars have been obtained by several groups. The results of these investigations are mixed. Some find C/O > 0.8 in more than 20% of stars, and C/O > .1.0 in more than 6%. Others find C/O > 0.8 in none of the sample stars. These works on solar-type stars are all differential abundance analyses with respect to the Sun and depend on the adopted C/O ratio in the Sun. Recently, a method of molecular line spectroscopy of M dwarfs, in. which carbon and oxygen abundances are derived respectively from CO and H2O lines in the K band, has been developed. The resolution of the K-band spectrum. is 20,000. Carbon and oxygen abundances of 46 M dwarfs have been obtained by this nondifferential abundance analysis. Carbon-to-oxygen ratios in M dwarfs derived by this method are more robust than those in solar-type stars derived from neutral carbon and oxygen lines in the visible spectra because of the difficulty in the treatment of oxygen lines. We have compared the frequency distribution of C/O distributions in M dwarfs with those of solar-type stars and have found that the. low frequency of high-C/O ratios is preferred.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available