Radial Velocity Monitoring and Analysis of Gaia Astrometry of Selected Intermediate Mass Stars to Constrain Their Multiplicity Status

TL;DR

This work targets the multiplicity status of 13 intermediate-mass stars by combining new radial velocity measurements from the FLECHAS spectrograph with Gaia DR3 wide-companion data. Eight stars show constant RV over the campaign, while five exhibit significant variability that is modeled with Keplerian orbits to yield orbital elements and mass functions for SB1/SB2 systems. Gaia DR3 astrometry further identifies wide companions, revealing complex hierarchies such as the hierarchical quadruple 17 Dra and the quintuple 7 CrB. The combined RV and astrometric approach provides a refined census of nearby bright multiple stars and emphasizes the critical role of long-baseline RV monitoring for accurate kinematic and multiplicity analyses.

Abstract

We present new radial velocity measurements of 13 selected intermediate mass stars (2 - 6 M$_\odot$). The measurements were performed between 29 April and 6 September 2024 at the University Observatory Jena using the échelle spectrograph FLECHAS. The radial velocity of eight stars was found to be constant during our spectroscopic monitoring, namely: 17 Dra A, HD 148374, HD 169487 A, 57 Cnc, $γ$ And, HD 11031, $κ$ And, and $λ$ Cas. In contrast, the radial velocity of five stars showed significant variability throughout or spectroscopic observation, namely: 7 CrB A, 7 CrB B, HD 214007, $ι$ Her, and HD 201433 A. In all these cases, Keplerian orbital solutions were fitted to the observational data and the orbital elements of these spectroscopic binary systems were determined. In addition, we searched for wide companions of our targets using the third data release from ESA's Gaia mission, in order to determine the multiplicity status of these stars and contribute to the census of bright, nearby multiple stars.

Figures (15)

• Figure 1: The RV of 17 Dra A measured over a period of 79 days. The mean RV is indicated by the dashed red line.
• Figure 2: The RV of HD 148374 measured over a period of 79 days. The mean RV is indicated by the dashed red line.
• Figure 3: The RV of HD 169487 A measured over a period of 91 days. The mean RV is indicated by the dashed red line.
• Figure 4: The RV of 57 Cnc measured over a period of 36 days. The mean RV is indicated by the dashed red line.
• Figure 5: The RV of $\gamma$ And measured over a period of 44 days. The mean RV is indicated by the dashed red line.