Giampapa, Mark

Contact Email: giampapa@noao.edu
Institute: National Solar Observatory
Subject Area: Other (Please Specify Below)
Waveband: Optical
Technique: Spectroscopy
Other: Solar-type stars
Presentation: Oral Contribution: Monday
Title: The Suns of M67
Abstract: I present an update on a long-term study of the solar-type stars in the solar-age and solar-metallicity open cluster, M67. The primary objective of this program is to gain insight on the possible range of solar chromospheric activity and the associated, potential long-term variability of the Sun through the observation of stellar analogs of the Sun. Spectra in the Ca II H & K line region of over 100 stars in M67 were obtained with the 3.5-m WIYN telescope and Hydra multi-object spectrograph on Kitt Peak. A long-term monitoring program to detect cycle-related variability of the chromospheric Ca II H&K emission in the solar-type members of M67 has also been initiated. We find that the distribution of chromospheric H&K line strengths in the solar-type stars is broader than the distribution of H&K line emission recorded in modern observations of the Sun, suggesting that the potential excursion in the amplitude of the solar cycle is greater than what we have seen so far in the contemporary record. The possibility that the distribution of H&K line strengths could arise from a dispersion in rotational velocities in this sample is also discussed.