The yellow hypergiants HR 8752 and rho Cassiopeiae near the evolutionary border of instability
arXiv:astro-ph/9908308 · doi:10.1086/312283
Abstract
High-resolution near-ultraviolet spectra of the yellow hypergiants HR 8752 and rho Cassiopeiae indicate high effective temperatures placing both stars near the T_eff border of the ``yellow evolutionary void''. At present, the temperature of HR 8752 is higher than ever. For this star we found Teff=7900+-200 K, whereas rho Cassiopeiae has Teff=7300+-200 K. Both, HR 8752 and rho Cassiopeiae have developed strong stellar winds with Vinf ~ 120 km/s and Vinf ~ 100 km/s, respectively. For HR 8752 we estimate an upper limit for the spherically symmetric mass-loss of 6.7X10^{-6}M_solar/yr. Over the past decades two yellow hypergiants appear to have approached an evolutionary phase, which has never been observed before. We present the first spectroscopic evidence of the blueward motion of a cool super/hypergiant on the HR diagram.
13 pages including 3 figures. Accepted for publication in ApJ Letters
References in corpus (1)
Cited by in corpus (12)
- Variable Star Network: World Center for Transient Object Astronomy and Variable Stars
- Crossing the `Yellow Void' -- Spatially Resolved Spectroscopy of the Post- Red Supergiant IRC+10420 and Its Circumstellar Ejecta
- High-Resolution Spectroscopy of the Yellow Hypergiant Rho Cassiopeiae from 1993 Through the Outburst of 2000-2001
- The Circumstellar Environments of NML Cyg and the Cool Hypergiants
- Radio emission from the massive stars in the Galactic Super Star Cluster Westerlund 1
- On the CO Near-IR Band and the Line Splitting Phenomenon in the Yellow Hypergiant Rho Cassiopeiae
- On the Dynamic Stability of Cool Supergiant Atmospheres
- Pulsations, eruptions, and evolution of four yellow hypergiants
- A new outburst of the yellow hypergiant star Rho Cas
- Unity and Diversity of Yellow Hypergiants Family
- Yellow hypergiant V509 Cas -- stable in the 'yellow void'
- Painting a Family Portrait of the Yellow Super- and Hypergiants in the Milky Way I. Constraining the Distances and Luminosities