Richard Irving Anderson

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Related publications (50)

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Mass of Cepheid V350 Sgr Incorporating Interferometry and the Companion Mass

Richard Irving Anderson, Giordano Viviani

The system V350 Sgr has a classical Cepheid for the primary. Interferometry is presented for the system, and the full orbit is determined. The mass of the companion has been determined from an International Ultraviolet Explorer spectrum and comparison with ...

IOP Publishing Ltd2025

The VELOCE modulation zoo II. Humps and splitting patterns in spectral lines of classical Cepheids

Richard Irving Anderson, Giordano Viviani, Henryka Ewa Netzel

Context. Line splitting in spectral lines is observed in various types of stars due to phenomena such as shocks, spectroscopic binaries, magnetic fields, spots, and nonradial modes. In pulsating stars, line splitting is often attributed to pulsation-induce ...

2025

Tip of the Red Giant Branch Distances with JWST. II. I-band Measurements in a Sample of Hosts of 10 Type Ia Supernova Match HST Cepheids

Richard Irving Anderson

The Hubble Tension, a >5σ discrepancy between direct and indirect measurements of the Hubble constant (H 0), has persisted for a decade and motivated intense scrutiny of the paths used to infer H 0. Comparing independently derived distances for a set of ga ...

2024

JWST Observations Reject Unrecognized Crowding of Cepheid Photometry as an Explanation for the Hubble Tension at 8σ Confidence

Richard Irving Anderson

We present high-definition observations with the James Webb Space Telescope (JWST) of >1000 Cepheids in a geometric anchor of the distance ladder, NGC 4258, and in five hosts of eight Type Ia supernovae, a far greater sample than previous studies with JWST ...

Iop Publishing Ltd2024

Variable stars in Galactic globular clusters: II. Population II Cepheids

Richard Irving Anderson, Mauricio Cruz Reyes

We identified a sample of 88 bona fide Population II Cepheids (henceforth referred to as Cepheids) and 44 candidates in Galactic globular clusters (GCs). Seventy-eight of the Cepheids in the sample align within 2 sigma of the period-luminosity relation for ...

EDP SCIENCES S A2025

Variable stars in galactic globular clusters I. The population of RR Lyrae stars

Zoé Lisa Medaric, Richard Irving Anderson, Mauricio Cruz Reyes, Henryka Ewa Netzel

We present a comprehensive catalog of 2824 RR Lyrae stars (RRLs) residing in 115 Galactic globular clusters (GCs). Our catalog includes 1594 fundamental-mode (RRab), 824 first-overtone (RRc), and 28 double-mode (RRd) RRLs, as well as 378 RRLs of an unknown ...

Edp Sciences S A2024

An Improved Calibration of the Wavelength Dependence of Metallicity on the Cepheid Leavitt Law

Richard Irving Anderson

The Cepheid period-luminosity (PL) relation (or Leavitt law) has served as the first rung of the most widely used extragalactic distance ladder and is central to the determination of the local value of the Hubble constant (H (0)). We investigate the influe ...

2022

New periodograms separating orbital radial velocities and spectral shape variation

Richard Irving Anderson

We present new periodograms that are effective in distinguishing Doppler shift from spectral shape variability in astronomical spectra. These periodograms, building upon the concept of partial distance correlation, separate the periodic radial velocity mod ...

2022

Standardized Luminosity of the Tip of the Red Giant Branch Utilizing Multiple Fields in NGC 4258 and the CATs Algorithm

Richard Irving Anderson

The tip of the red giant branch provides a luminous standard candle for calibrating distance ladders that reach Type Ia supernova (SN Ia) hosts. However, recent work reveals that tip measurements vary at the similar to 0.1 mag level for different stellar p ...

Iop Publishing Ltd2023

The span of space

Richard Irving Anderson

Twinkle, twinkle little star, tell me just how far you are. Richard I. Anderson discusses standard candles and their applications. ...

NATURE PORTFOLIO2024