47 citations · 198 across the 17 of their papers we have counts for
18 papers
The Contribution of Starspots to the Lithium Spread in NGC 2264
Yan Luo, Gregory J. Herczeg, Min Fang +2
Star clusters with ages of a few Myr have a previously unexplained dispersion in the lithium equivalent widths. In this work, we show that much of the lithium spread of the young c…
WOCS XCIII: NGC 7789: the Evolution of Li, Stellar Rotation, and Extended Main Sequence Turnoffs
Barbara J. Anthony-Twarog, Samantha W. Brunker, Constantine P. Deliyannis +4
Precision UBVRI photometry of NGC 7789 is combined with Gaia data to map reddening variations across the cluster face. HYDRA spectra, Gaia astrometry, and isochrone fitting constra…
Lithium Abundances of Main-Sequence Stars in the Old Open Cluster NGC 188: Probes of Stellar Evolution Beyond the Solar Age
Qinghui Sun, Constantine P. Deliyannis, Bruce A. Twarog +1
We present lithium abundances for 119 main-sequence stars in the old open cluster NGC 188 (age = 6.3 Gyr), using high-resolution, high signal-to-noise ratio spectra from WIYN/Hydra…
Subgiants in NGC 188 Reveal that Rotationally Induced Mixing Creates the Main Sequence Li-Dip
Qinghui Sun, Constantine P. Deliyannis, Barbara J. Anthony-Twarog +3
The "Li-Dip" is an unexpected, striking, and highly non-standard anomaly of severe lithium depletion observed in mid-F dwarf stars, which has puzzled astronomers for nearly 40 year…
Planets Around Solar Twins/Analogs (PASTA) I.: High precision stellar chemical abundance for 17 planet-hosting stars and the condensation temperature trend
Qinghui Sun, Sharon Xuesong Wang, Tianjun Gan +30
The Sun is depleted in refractory elements compared to nearby solar twins, which may be linked to the formation of giant or terrestrial planets. Here we present high-resolution, hi…
C3PO III: On the Lithium Signatures Following Planet Engulfment by Stars
Qinghui Sun, Yuan-Sen Ting, Fan Liu +8
Planet engulfment has been identified as one of the mechanisms for enhancing lithium abundance in stars. However, comprehensive investigations into lithium signatures following suc…
Li Evolution Among Stars of Low/Intermediate Mass: The Metal-Deficient Open Cluster, NGC 2204
Barbara J. Anthony-Twarog, Constantine P. Deliyannis, Aaron Steinhauer +2
We have analyzed high-dispersion spectra in the Li 6708 Angstrom region for 167 stars within the anticenter cluster, NGC 2204. From 105 probable members, abundance analysis of 45 e…
A revisit of the Mass-Metallicity Trends in Transiting Exoplanets
Qinghui Sun, Sharon Xuesong Wang, Luis Welbanks +2
The two prevailing planet formation scenarios, core-accretion and disk instability, predict distinct planetary mass-metallicity relations. Yet, the detection of this trend remains…
A search for stellar siblings of the ~ 200 Myr TOI-251b planetary system
Qinghui Sun, Sharon Xuesong Wang, Andrew W. Mann +4
Young planets (< 1 Gyr) are helpful for studying the physical processes occurring at the early stage of planet evolution. TOI-251 b is a recently discovered sub-Neptune orbiting a…
WIYN Open Cluster Study 89. M48 (NGC 2548) 2: Lithium Abundances in the 420 Myr Open Cluster M48 From Giants Through K Dwarfs
Qinghui Sun, Constantine P. Deliyannis, Aaron Steinhauer +2
We consider WIYN/Hydra spectra of 329 photometric candidate members of the 420-Myr-old open cluster M48, and report Lithium detections or upper limits for 234 members and likely me…
Three low-mass companions around aged stars discovered by TESS
Zitao Lin, Tianjun Gan, Sharon X. Wang +42
We report the discovery of three transiting low-mass companions to aged stars: a brown dwarf (TOI-2336b) and two objects near the hydrogen burning mass limit (TOI-1608b and TOI-252…
A Search for Exoplanets in Open Clusters and Young Associations based on TESS Objects of Interest
Qinghui Sun, Sharon Xuesong Wang, Tianjun Gan +1
We report the results of our search of planet candidates in Open Clusters and Young Stellar Associations based on the TESS Objects of Interest Catalog. We find one confirmed planet…
WIYN Open Cluster Study: The Old Open Cluster, NGC 188, and a Re-evaluation of Lithium-Richness Among Red Giants
Qinghui Sun, Constantine P. Deliyannis, Bruce A. Twarog +3
We present WIYN/Hydra spectra of 34 red giant candidate members of NGC 188, which, together with WOCS and Gaia data yield 23 single members, 6 binary members, 4 single nonmembers,…
The effects of rotation on the lithium depletion of G- and K-dwarfs in Messier 35
R. D. Jeffries, R. J. Jackson, Qinghui Sun +1
New fibre spectroscopy and radial velocities from the WIYN telescope are used to measure photospheric lithium in 242 high-probability, zero-age-main-sequence (ZAMS) F- to K-type me…
WIYN Open Cluster Study LXXIX. M48 (NGC 2548) I. Radial Velocities, Rotational Velocities, and Metallicities of Stars in the Open Cluster M48 (NGC 2548)
Qinghui Sun, Constantine P. Deliyannis, Aaron Steinhauer +2
WIYN/Hydra spectra (R 13,500, signal-to-noise pixel = 50-1000) of a 400 $\unicode{x212B}$ region around Li 6708 $\unicode{x212B}$ are used to determine radial and rot…
WIYN Open Cluster Study LXXX: HDI CCD Photometry of the Old Open Cluster NGC 7142 and Comparison to M67
Qinghui Sun, Constantine P. Deliyannis, Bruce A. Twarog +2
We present photometry of 8702 stars in a field in the direction of NGC 7142, taken with the Half Degree Imager (HDI) at the WIYN 0.9-meter tele…
A search for radius inflation among active M-dwarfs in Praesepe
R. J. Jackson, R. D. Jeffries, Constantine P. Deliyannis +2
Rotation periods from Kepler K2 are combined with projected rotation velocities from the WIYN 3.5-m telescope, to determine projected radii for fast-rotating, low-mass ($0.15 \leq…
Li in Open Clusters: Cool Dwarfs in the Young, Subsolar Metallicity Cluster M35 (NGC 2168)
B. J. Anthony-Twarog, C. P. Deliyannis, D. Harmer +4
Hydra spectra of 85 G-K dwarfs in the young cluster, M35, near the Li 6708 Angstrom line region are analyzed. From velocities and Gaia astrometry, 78 are likely single-star members…