We present results from an ongoing Keck spectroscopic survey of red giant stars in a field located along the major axis of M31, ≈ 34 kpc in projection from the nucleus and near the luminous globular cluster G1. We use multislit LRIS spectroscopy to measure the Ca ii nearinfrared triplet in 41 stars ranging in apparent magnitude from 20 < I < 22. Of these, 23 stars are found to have radial veloc...

In searches for planetary transits in the field, well over half of the survey stars are typically giants or other stars that are too large to permit straightforward detection of planets. For all-sky searches of bright V 11 stars, the fraction is ∼ 90%. We show that the great majority of these contaminants can be removed from the sample by analyzing their reduced proper motions (RPMs): giants ha...

Abstract The puzzle of the Li-rich giant is still unsolved, contradicting prediction standard stellar models. Although exact evolutionary stages play a key role in knowledge giants, limited number giants have been observed with high-quality asteroseismic parameters to clearly distinguish stages. Based on LAMOST Data Release 7 (DR7), we applied data-driven neural network method derive for stars,...

We present results from an ongoing Keck spectroscopic survey of red giant stars in a field located along the major axis of M31, ≈ 34 kpc in projection from the nucleus and near the luminous globular cluster G1. We use multislit LRIS spectroscopy to measure the Ca ii nearinfrared triplet in 41 stars ranging in apparent magnitude from 20 < I < 22. Of these, 23 stars are found to have radial veloc...

In searches for planetary transits in the field, well over half of the survey stars are typically giants or other stars that are too large to permit straightforward detection of planets. For all-sky searches of bright Vd11 stars, the fraction is 90%. We show that the great majority of these contaminants can be removed from the sample by analyzing their reduced proper motions (RPMs); giants have...

An analysis of the CN and CH band strengths measured in a large sample of M71 and M13 main sequence stars by Cohen (1999a,b) is undertaken using synthetic spectra to quantify the underlying C and N abundances. In the case of M71 it is found that the observed CN and CH band strengths are best matched by the identical C/N/O abundances which fit the bright giants, implying: 1) little if any mixing...

We present period-luminosity relations for more than 23,000 red giants in the Large Magellanic Cloud observed by the OGLE-II microlensing project. The OGLE period values were combined with the 2MASS single-epoch JHKS photometric data. For the brighter stars we find agreement with previous results (four different sequences corresponding to different modes of pulsation in AGB stars). We also disc...

We present period-luminosity relations for more than 23,000 red giants in the Large Magellanic Cloud observed by the OGLE-II microlensing project. The OGLE period values were combined with the 2MASS single-epoch JHKS photometric data. For the brighter stars we find agreement with previous results (four different sequences corresponding to different modes of pulsation in AGB stars). We also disc...

We present results from an ongoing Keck spectroscopic survey of red giant stars in a field located along the major axis of M31, ≈ 34 kpc in projection from the nucleus and near the luminous globular cluster G1. We use multislit LRIS spectroscopy to measure the Ca ii nearinfrared triplet in 41 stars ranging in apparent magnitude from 20 < I < 22. Of these, 23 stars are found to have radial veloc...

Deep UBRI images of a 15 × 15 field in the outer spheroid of the M31 galaxy obtained using the Kitt Peak National Observatory 4-meter telescope, and I band images obtained with the Keck 10-meter telescope and Low Resolution Imaging Spectrograph, are used to isolate a sample of candidate red giant branch stars located at a projected radial distance of 19 kpc along the minor axis. These stars are...