The Stellar Observations Network Group (SONG) -- A Legacy Archive of Stellar Time-Domain Spectroscopy

@misc{lund2026stellar,
  title = {{The Stellar Observations Network Group (SONG) -- A Legacy Archive of Stellar Time-Domain Spectroscopy}},
  author = {M. N. Lund and F. Grundahl and M. S. Fredslund and P. L. Pallé and S. Simon-Diaz and J. Christensen-Dalsgaard and R. A. Wittenmyer and L. Deng and J. Jackiewicz and H. Kjeldsen and V. Antoci and H. Korhonen and S. H. Albrecht and K. Wang and J. Rudrasingam and R. Handberg and T. R. Bedding and J. L. Rørsted and P. M. Sørensen and D. J. Wright and J. A. Holtzman and J. Klusmeyer and S. Frandsen and E. Weiss and J. Jessen-Hansen and P. Heeren and R. Tronsgaard and T. Arentoft and P. G. Beck and U. G. Jørgensen and A. N. Sørensen and M. I. Andersen and P. Kjærgaard and M. Bizzarro and R. P. Butler and E. Corsaro and R. A. García and D. Stello and S. Murphy and J. Horner and S. Martell and M. J. Martínez González and L. Casagrande and J. Lattanzio},
  howpublished = {arXiv},
  year = {2026},
  month = aug,
  doi = {10.48550/arxiv.2607.02775},
  eprint = {2607.02775},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2607.02775},
  note = {CC BY-NC-ND 4.0},
}

TY  - UNPB
TI  - The Stellar Observations Network Group (SONG) -- A Legacy Archive of Stellar Time-Domain Spectroscopy
AU  - M. N. Lund
AU  - F. Grundahl
AU  - M. S. Fredslund
AU  - P. L. Pallé
AU  - S. Simon-Diaz
AU  - J. Christensen-Dalsgaard
AU  - R. A. Wittenmyer
AU  - L. Deng
AU  - J. Jackiewicz
AU  - H. Kjeldsen
AU  - V. Antoci
AU  - H. Korhonen
AU  - S. H. Albrecht
AU  - K. Wang
AU  - J. Rudrasingam
AU  - R. Handberg
AU  - T. R. Bedding
AU  - J. L. Rørsted
AU  - P. M. Sørensen
AU  - D. J. Wright
AU  - J. A. Holtzman
AU  - J. Klusmeyer
AU  - S. Frandsen
AU  - E. Weiss
AU  - J. Jessen-Hansen
AU  - P. Heeren
AU  - R. Tronsgaard
AU  - T. Arentoft
AU  - P. G. Beck
AU  - U. G. Jørgensen
AU  - A. N. Sørensen
AU  - M. I. Andersen
AU  - P. Kjærgaard
AU  - M. Bizzarro
AU  - R. P. Butler
AU  - E. Corsaro
AU  - R. A. García
AU  - D. Stello
AU  - S. Murphy
AU  - J. Horner
AU  - S. Martell
AU  - M. J. Martínez González
AU  - L. Casagrande
AU  - J. Lattanzio
PY  - 2026
DA  - 2026/08/28
PB  - arXiv
DO  - 10.48550/arxiv.2607.02775
UR  - https://arxiv.org/abs/2607.02775
AB  - The Stellar Observations Network Group (SONG) network has operated for more than a decade, providing long-baseline, high-cadence spectroscopic observations of bright stars and the Sun. The observations, from 2014 through 2025, constitute a substantial archive of high-resolution spectra and precise radial velocities for a broad range of time-domain stellar astrophysics. We present an overview of the status, instrumentation, and scientific capabilities of the SONG network, and describe the scope and accessibility of the SONG Data Archive (SODA). We further illustrate the breadth of science enabled by SONG observations, including asteroseismology, stellar variability studies, binary-star characterisation, and exoplanet research. We summarise the operational status and observing strategies of the SONG facilities, describe the available data products and archive infrastructure, and outline procedures for accessing archival observations and proposing new observations within the SONG community framework. The SODA archive currently contains more than 580,000 spectra of 3091 stars obtained with SONG using either iodine-cell or Thorium-Argon wavelength calibration. The archive spans over a decade and includes extensive time-series data for bright targets across a wide range of stellar types and variability classes. Access to the archive is available to members of the SONG community, which remains open to new participants who agree to follow the community policies. The SONG archive has developed into a major long-baseline resource for stellar spectroscopy and radial-velocity time-series analysis. Continued expansion of the archive, together with coordinated observations obtained contemporaneously with TESS and future PLATO observations, is expected to enable new studies of stellar oscillations, variability, and exoplanet host stars through combined radial-velocity and photometric analyses.
ER  -