Publications (55)
Discovery of a Dynamical Cold Point in the Heart of the Sagittarius dSph Galaxy with Observations from the APOGEE Project
Steven R. Majewski, Sten Hasselquist, Ewa L. Åokas +30
The dynamics of the core of the Sagittarius (Sgr) dwarf spheroidal (dSph) galaxy are explored using high-resolution (R~22,500), H-band, near-infrared spectra of over 1,000 giant st…
A Harsh Test of Far-Field Scrambling with the Habitable Zone Planet Finder and the Hobby Eberly Telescope
Shubham Kanodia, Samuel Halverson, Joe P. Ninan +18
The Habitable zone Planet Finder (HPF) is a fiber fed precise radial velocity spectrograph at the 10 m Hobby Eberly Telescope (HET). Due to its fixed altitude design, the HET pupil…
Stable fiber-illumination for extremely precise radial velocities with NEID
Shubham Kanodia, Andrea S. J. Lin, Emily Lubar +24
NEID is a high-resolution red-optical precision radial velocity (RV) spectrograph recently commissioned at the WIYN 3.5 m telescope at Kitt Peak National Observatory, Arizona, USA.…
A Mini-Neptune and a Venus-Zone Planet in the Radius Valley Orbiting the Nearby M2-dwarf TOI-1266: Validation with the Habitable-zone Planet Finder
Gudmundur Stefansson, Ravi Kopparapu, Andrea Lin +26
We report on the validation of two planets orbiting the nearby (36pc) M2 dwarf TOI-1266 observed by the TESS mission. The inner planet is sub-Neptune-sized ($R=2.46 \pm 0.08 R_\opl…
44 New & Known M Dwarf Multiples In The SDSS-III/APOGEE M Dwarf Ancillary Science Sample
Jacob Skinner, Kevin R. Covey, Chad F. Bender +28
Binary stars make up a significant portion of all stellar systems. Consequently, an understanding of the bulk properties of binary stars is necessary for a full picture of star for…
Evidence for He I 10830 Ã ~ absorption during the transit of a warm Neptune around the M-dwarf GJ 3470 with the Habitable-zone Planet Finder
Joe P. Ninan, Gudmundur Stefansson, Suvrath Mahadevan +21
Understanding the dynamics and kinematics of out-flowing atmospheres of hot and warm exoplanets is crucial to understanding the origins and evolutionary history of the exoplanets n…
A close-in puffy Neptune with hidden friends: The enigma of TOI 620
Michael A. Reefe, Rafael Luque, Eric Gaidos +82
We present the validation of a transiting low-density exoplanet orbiting the M2.5 dwarf TOI 620 discovered by the NASA TESS mission. We utilize photometric data from both TESS and…
TOI-1696 and TOI-2136: Constraining the Masses of Two Mini-Neptunes with HPF
Corey Beard, Paul Robertson, Shubham Kanodia +29
We present the validation of two planets orbiting M dwarfs, TOI-1696b and TOI-2136b. Both planets are mini-Neptunes orbiting nearby stars, making them promising prospects for atmos…
Characterization of low-mass companions to objects of interest observed with APOGEE-N
Caleb I. Cañas, Chad F. Bender, Suvrath Mahadevan +12
We report the characterization of 28 low-mass () companions to objects of interest (KOIs), eight…
Extreme Precision Radial Velocity Working Group Final Report
Jonathan Crass, B. Scott Gaudi, Stephanie Leifer +33
Precise mass measurements of exoplanets discovered by the direct imaging or transit technique are required to determine planet bulk properties and potential habitability. Furthermo…
Homogeneous Analysis of Globular Clusters from the APOGEE Survey with the BACCHUS Code. II. The Southern Clusters and Overview
Szabolcs Mészáros, Thomas Masseron, D. A. GarcÃa-Hernández +33
We investigate the Fe, C, N, O, Mg, Al, Si, K, Ca, Ce and Nd abundances of 2283 red giant stars in 31 globular clusters from high-resolution spectra observed in both the northern a…
A sub-Neptune sized planet transiting the M2.5-dwarf G 9-40: Validation with the Habitable-zone Planet Finder
Gudmundur Stefansson, Caleb Cañas, John Wisniewski +32
We validate the discovery of a 2 Earth radii sub-Neptune-size planet around the nearby high proper motion M2.5-dwarf G 9-40 (EPIC 212048748), using high-precision near-infrared (NI…
Discovery of Two Rare Rigidly-Rotating Magnetosphere Stars in the APOGEE Survey
Stephen S. Eikenberry, S. Drew Chojnowski, John Wisniewski +19
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) - one of the Sloan Digital Sky Survey III programs -- is using near-infrared spectra of red giant…
MARVELS-1b: A Short-Period, Brown Dwarf Desert Candidate from the SDSS-III MARVELS Planet Search
Brian L. Lee, Jian Ge, Scott W. Fleming +59
We present a new short-period brown dwarf candidate around the star TYC 1240-00945-1. This candidate was discovered in the first year of the Multi-object APO Radial Velocity Exopla…
Observing the Sun as a star: Design and early results from the NEID solar feed
Andrea S. J. Lin, Andrew Monson, Suvrath Mahadevan +27
Efforts with extreme-precision radial velocity (EPRV) instruments to detect small-amplitude planets are largely limited, on many timescales, by the effects of stellar variability a…
TOI-5375 B: A Very Low Mass Star at the Hydrogen-Burning Limit Orbiting an Early M-type Star
Mika Lambert, Chad F. Bender, Shubham Kanodia +16
The TESS mission detected a companion orbiting TIC 71268730, categorized it as a planet candidate, and designated the system TOI-5375. Our follow-up analysis using radial velocity…
Persistent starspot signals on M dwarfs: multi-wavelength Doppler observations with the Habitable-zone Planet Finder and Keck/HIRES
Paul Robertson, Gudmundur Stefansson, Suvrath Mahadevan +23
Young, rapidly-rotating M dwarfs exhibit prominent starspots, which create quasiperiodic signals in their photometric and Doppler spectroscopic measurements. The periodic Doppler s…
The First APOKASC Catalog of Kepler Dwarf and Subgiant Stars
Aldo Serenelli, Jennifer Johnson, Daniel Huber +23
(Abridged) We present the first APOKASC catalog of spectroscopic and asteroseismic data for 415 dwarfs and subgiants. Asteroseismic data have been obtained by Kepler in short caden…
Sodium and Oxygen Abundances in the Open Cluster NGC 6791 from APOGEE H-Band Spectroscopy
Katia Cunha, Verne V. Smith, Jennifer A. Johnson +27
The open cluster NGC 6791 is among the oldest, most massive and metal-rich open clusters in the Galaxy. High-resolution -band spectra from the Apache Point Observatory Galactic…
An efficient, compact, and versatile fiber double scrambler for high precision radial velocity instruments
Samuel Halverson, Arpita Roy, Suvrath Mahadevan +5
We present the design and test results of a compact optical fiber double-scrambler for high-resolution Doppler radial velocity instruments. This device consists of a single optic:…
A comprehensive radial velocity error budget for next generation Doppler spectrometers
Samuel Halverson, Ryan Terrien, Suvrath Mahadevan +14
We describe a detailed radial velocity error budget for the NASA-NSF Extreme Precision Doppler Spectrometer instrument concept NEID (NN-explore Exoplanet Investigations with Dopple…
An eccentric Brown Dwarf eclipsing an M dwarf
Caleb I. Cañas, Suvrath Mahadevan, Chad F. Bender +16
We report the discovery of a brown dwarf transiting the early M dwarf TOI-2119 on an eccentric orbit () at an orbital period of $7.2008…
Stellar Spectroscopy in the Near-infrared with a Laser Frequency Comb
Andrew J. Metcalf, Tyler Anderson, Chad F. Bender +34
The discovery and characterization of exoplanets around nearby stars is driven by profound scientific questions about the uniqueness of Earth and our Solar System, and the conditio…
The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA Derived Quantities, Data Visualization Tools and Stellar Library
D. S. Aguado, Romina Ahumada, Andres Almeida +230
Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years o…
Development of a New, Precise Near-infrared Doppler Wavelength Reference: A Fiber Fabry-Perot Interferometer
Samuel Halverson, Suvrath Mahadevan, Lawrence Ramsey +5
We present the ongoing development of a commercially available Micron Optics fiber-Fabry Perot Interferometer as a precise, stable, easy to use, and economic spectrograph reference…
Quiet Please: Detrending Radial Velocity Variations from Stellar Activity with a Physically Motivated Spot Model
Jared C. Siegel, Samuel Halverson, Jacob K. Luhn +15
For solar-type stars, spots and their associated magnetic regions induce radial velocity perturbations through the Doppler rotation signal and the suppression of convective blueshi…
The Habitable-Zone Planet Finder: A Stabilized Fiber-Fed NIR Spectrograph for the Hobby-Eberly Telescope
Suvrath Mahadevan, Lawrence Ramsey, Chad Bender +12
We present the scientific motivation and conceptual design for the recently funded Habitable-zone Planet Finder (HPF), a stabilized fiber-fed near-infrared (NIR) spectrograph for t…
The APOGEE Spectroscopic Survey of Kepler Planet Hosts: Feasibility, Efficiency, and First Results
Scott W. Fleming, Suvrath Mahadevan, Rohit Deshpande +33
The Kepler mission has yielded a large number of planet candidates from among the Kepler Objects of Interest (KOIs), but spectroscopic follow-up of these relatively faint stars is…
The Sixteenth Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
Romina Ahumada, Carlos Allende Prieto, Andres Almeida +310
This paper documents the sixteenth data release (DR16) from the Sloan Digital Sky Surveys; the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of…
TOI-3757 b: A low density gas giant orbiting a solar-metallicity M dwarf
Shubham Kanodia, Jessica Libby-Roberts, Caleb I. Canas +32
We present the discovery of a new Jovian-sized planet, TOI-3757 b, the lowest density planet orbiting an M dwarf (M0V). It orbits a solar-metallicity M dwarf discovered using TESS…
Gaia 20eae: A newly discovered episodically accreting young star
Arpan Ghosh, Saurabh Sharma, Joe. P. Ninan +18
The Gaia Alert System issued an alert on 2020 August 28, on Gaia 20eae when its light curve showed a 4.25 magnitude outburst. We present multi-wavelength photometric and spec…
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
Bela Abolfathi, D. S. Aguado, Gabriela Aguilar +344
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourtee…
Rotational modulation of spectroscopic Zeeman signatures in low-mass stars
Ryan C. Terrien, Allison Keen, Katy Oda +24
Accurate tracers of the stellar magnetic field and rotation are cornerstones for the study of M dwarfs and for reliable detection and characterization of their exoplanetary compani…
The Habitable-zone Planet Finder Detects a Terrestrial-mass Planet Candidate Closely Orbiting Gliese 1151: The Likely Source of Coherent Low-frequency Radio Emission from an Inactive Star
Suvrath Mahadevan, Guðmundur Stefánsson, Paul Robertson +17
The coherent low-frequency radio emission detected by LOFAR from Gliese 1151, a quiescent M4.5 dwarf star, has radio emission properties consistent with theoretical expectations of…
The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data
Abdurro'uf, Katherine Accetta, Conny Aerts +337
This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete…
Companions to APOGEE Stars I: A Milky Way-Spanning Catalog of Stellar and Substellar Companion Candidates and their Diverse Hosts
Nicholas W. Troup, David L. Nidever, Nathan De Lee +24
In its three years of operation, the Sloan Digital Sky Survey (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE-1) observed 14,000 stars with enough epoc…
TOI-5344 b: A Saturn-like planet orbiting a super-Solar metallicity M0 dwarf
Te Han, Paul Robertson, Shubham Kanodia +19
We confirm the planetary nature of TOI-5344 b as a transiting giant exoplanet around an M0 dwarf star. TOI-5344 b was discovered with the Transiting Exoplanet Survey Satellite phot…
Target Prioritization and Observing Strategies for the NEID Earth Twin Survey
Arvind F. Gupta, Jason T. Wright, Paul Robertson +16
NEID is a high-resolution optical spectrograph on the WIYN 3.5-m telescope at Kitt Peak National Observatory and will soon join the new generation of extreme precision radial veloc…
The Aligned Orbit of WASP-148b, the Only Known Hot Jupiter with a Nearby Warm Jupiter Companion, from NEID and HIRES
Xian-Yu Wang, Malena Rice, Songhu Wang +39
We present spectroscopic measurements of the Rossiter-McLaughlin effect for WASP-148b, the only known hot Jupiter with a nearby warm-Jupiter companion, from the WIYN/NEID and Keck/…
Development of Fiber Fabry-Perot Interferometers as Stable Near-infrared Calibration Sources for High Resolution Spectrographs
Samuel Halverson, Suvrath Mahadevan, Lawrence Ramsey +10
We discuss the ongoing development of single-mode fiber Fabry-Perot (FFP) Interferometers as precise astro-photonic calibration sources for high precision radial velocity (RV) spec…
A hot Mars-sized exoplanet transiting an M dwarf
Caleb I. Cañas, Suvrath Mahadevan, William D. Cochran +21
We validate the planetary nature of an ultra-short period planet orbiting the M dwarf KOI-4777. We use a combination of space-based photometry from Kepler, high-precision, near-inf…
A warm Jupiter transiting an M dwarf: A TESS single transit event confirmed with the Habitable-zone Planet Finder
Caleb I. Cañas, Gudmundur Stefansson, Shubham Kanodia +30
We confirm the planetary nature of a warm Jupiter transiting the early M dwarf TOI-1899, using a combination of available TESS photometry; high-precision, near-infrared spectroscop…
The Puzzling Li-rich Red Giant Associated with NGC 6819
Joleen K. Carlberg, Verne V. Smith, Katia Cunha +13
A Li-rich red giant star (2M19411367+4003382) recently discovered in the direction of NGC 6819 belongs to the rare subset of Li-rich stars that have not yet evolved to the luminosi…
The Habitable-zone Planet Finder Calibration System
Samuel Halverson, Suvrath Mahadevan, Lawrence Ramsey +9
We present the design concept of the wavelength calibration system for the Habitable-zone Planet Finder instrument (HPF), a precision radial velocity (RV) spectrograph designed to…
An extreme test case for planet formation: a close-in Neptune orbiting an ultracool star
Gudmundur Stefansson, Suvrath Mahadevan, Yamila Miguel +27
In current theories of planet formation, close-orbiting planets as massive as Neptune are expected to be very rare around low-mass stars. We report the discovery of a Neptune-mass…
The Warm Neptune GJ 3470b has a Polar Orbit
Gudmundur Stefansson, Suvrath Mahadevan, Cristobal Petrovich +34
The warm Neptune GJ 3470b transits a nearby (pc) bright slowly rotating M1.5-dwarf star. Using spectroscopic observations during two transits with the newly commissioned NEID…
Time-resolved p-mode oscillations for subgiant HD 142091 with NEID at WIYN
Jacob K. Luhn, Paul Robertson, Samuel Halverson +22
Detections of Earth-analog planets in radial velocity observations are limited by stellar astrophysical variability occurring on a variety of timescales. Current state-of-the-art m…
The Thirteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey MApping Nearby Galaxies at Apache Point Observatory
SDSS Collaboration, Franco D. Albareti, Carlos Allende Prieto +335
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in July 2014. It pursues three core programs: APOGEE-2, MaNGA, and eBOSS. In addition, eBOSS cont…
Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
Michael R. Blanton, Matthew A. Bershady, Bela Abolfathi +350
We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOG…
iLocater: A Diffraction-limited Doppler Spectrometer for the Large Binocular Telescope
Justin R. Crepp, Jonathan Crass, David King +31
We are developing a stable and precise spectrograph for the Large Binocular Telescope (LBT) named "iLocater." The instrument comprises three principal components: a cross-dispersed…
Non-detection of Helium in the upper atmospheres of TRAPPIST-1b, e and f
Vigneshwaran Krishnamurthy, Teruyuki Hirano, Guðmundur Stefánsson +37
We obtained high-resolution spectra of the ultra-cool M-dwarf TRAPPIST-1 during the transit of its planet `b' using two high dispersion near-infrared spectrographs, IRD instrument…
Searching for GEMS: TOI-5688 A b, a low-density giant orbiting a high-metallicity early M-dwarf
Varghese Reji, Shubham Kanodia, Joe Ninan +31
We present the discovery of a low-density planet orbiting the high-metallicity early M-dwarf TOI-5688 A b. This planet was characterized as part of the search for transiting giant…
Broadband stability of the Habitable Zone Planet Finder Fabry-Pérot etalon calibration system: evidence for chromatic variation
Ryan C Terrien, Joe P Ninan, Scott A Diddams +11
The comb-like spectrum of a white light-illuminated Fabry-Pérot etalon can serve as a cost-effective and stable reference for precise Doppler measurements. Understanding the stabi…
TOI-1728b: The Habitable-zone Planet Finder confirms a warm super Neptune orbiting an M dwarf host
Shubham Kanodia, Caleb I. Canas, Gudmundur Stefansson +23
We confirm the planetary nature of TOI-1728b using a combination of ground-based photometry, near-infrared Doppler velocimetry and spectroscopy with the Habitable-zone Planet Finde…
The Habitable-zone Planet Finder Reveals A High Mass and a Low Obliquity for the Young Neptune K2-25b
Gudmundur Stefansson, Suvrath Mahadevan, Marissa Maney +27
Using radial-velocity data from the Habitable-zone Planet Finder, we have measured the mass of the Neptune-sized planet K2-25b, as well as the obliquity of its M4.5-dwarf host star…