Stellar And Orbital Characterization Of Three Low Mass M Dwarf Binary Stars With Dynamical Spectroscopy From The Habitable Zone Planet Finder

Contrast curves and reconstructed images from the NESSI speckle imager for a: LSPM 0515+5911, b: NLTT 45468, and c: NLTT 43564. Neither LSPM 0515+5911 nor NLTT 43564 show companions within the field that could contaminate the HPF observations. NLTT 45468 shows a nearby star at 2.1” in the lower left of the inset in b; the signal in the upper right is an artifact of the speckle processing. — astro-ph.SR

Theoretical models of low-mass stars continue to be discrepant with observations when used to examine the mass-radius relationship and other physical parameters of individual stars. High-resolution spectroscopy that leads to dynamical measurements of binary stars can directly improve these models.

We have been using the Habitable-zone Planet Finder spectrograph to monitor binary stars with M dwarf components. Here, we measure the orbital and stellar parameters for three such systems: LSPM J0515+5911, NLTT 43564, and NLTT 45468. Each system has dozens of spectra obtained over a baseline of several years.

None of the systems appear to be eclipsing, so our ability to turn them into true benchmark binaries with purely dynamical measurements is limited. We use literature photometry to estimate each system’s spectral energy distribution and utilize models in combination with detection limits of our spectroscopic measurements to probe characteristics of the companions.

LSPM J0515+5911 is a double-lined spectroscopic binary with period of 126.948±0.029 days and derived minimum masses, M₁sin³i=0.058±0.002 M_⊙ and M₂sin³i=0.046±0.001 M_⊙ for the primary and secondary components, respectively.

We solved NLTT 43564 with period of 1877±24 days and NLTT 45468 with period of 9.686±0.001 days as single lined systems, and modeled the primary masses to be M1=0.32±0.02 M_⊙ and M₁=0.35+0.02−0.07 M_⊙, respectively.

Suhani Surana, Chad F. Bender, Caleb I. Cañas, Daniel M. Krolikowski, William D. Cochran, Mark Everett, Arvind F. Gupta, Shubham Kanodia, Suvrath Mahadevan, Andrew Monson, Joe P. Ninan, Leonardo A. Paredes, Paul Robertson, Arpita Roy, Christian Schwab, Gudmundur Stefansson

Comments: 20 pages, 7 figures, Accepted for Publication in the Astronomical Journal
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2601.19996 [astro-ph.SR] (or arXiv:2601.19996v1 [astro-ph.SR] for this version)
https://doi.org/10.48550/arXiv.2601.19996
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Submission history
From: Suhani Surana
[v1] Tue, 27 Jan 2026 19:06:05 UTC (3,901 KB)
https://arxiv.org/abs/2601.19996
Astrobiology