English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report new interferometric angular diameter observations of 41 carbonstars observed with the Palomar Testbed Interferometer (PTI). Two of thesestars are CH carbon stars and represent the first such measurements for thissubtype. Of these, 39 have Yamashita (1972,1975) spectral classes and are ofsufficiently high quality that we may determine the dependence of effectivetemperature on spectral type. We find that there is a tendency for theeffective temperature to increase with increasing temperature index by ~120Kper step, starting at T_EFF ~= 2500K for C3,y, although there is a large amountof scatter about this relationship. Overall, the median effective temperaturefor the carbon star sample is found to be 2800 +- 270K, and the median linearradius is 360 +- 100 R_SUN. We also find agreement on average within 15K withthe T_EFF determinations of Bergeat (2001,2002a,b), and a refinement of carbonstar angular size prediction based on V & K magnitudes is presented that isgood to an rms of 12%. A subsample of our stars have sufficient {u,v} coverageto permit non-spherical modeling of their photospheres, and a general tendencyfor detection of statistically significant departures from sphericity withincreasing signal-to-noise of the interferometric data is seen. Theimplications of most - and potentially all - carbon stars being non-sphericalis considered in the context of surface inhomogeneities and a rotation-massloss connection.

The PTI Carbon Star Angular Size Survey: Effective Temperatures and Non-Sphericity