TY - JOUR
T1 - A blue ring nebula from a stellar merger several thousand years ago
AU - Hoadley, Keri
AU - Martin, D. Christopher
AU - Metzger, Brian D.
AU - Seibert, Mark
AU - McWilliam, Andrew
AU - Shen, Ken J.
AU - Neill, James D.
AU - Stefansson, Gudmundur
AU - Monson, Andrew
AU - Schaefer, Bradley E.
N1 - Funding Information:
Acknowledgements This research is based on observations made with GALEX, obtained from the MAST data archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy under NASA contract NAS 5–26555. Some of the data presented were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership between the California Institute of Technology, the University of California and NASA. This research made use of the Keck Observatory Archive, which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute, under contract with NASA, and made possible by the financial support of the W. M. Keck Foundation. We recognize and acknowledge the very important cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are fortunate to have the opportunity to conduct observations from this mountain. Some of the data presented were obtained at the Palomar Observatory. This research made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. We thank V. Scowcroft for obtaining Spitzer/IRAC photometry of TYC 2597-735-1. Funding for APASS was provided by the Robert Martin Ayers Sciences Fund. The DASCH data from the Harvard archival plates was partially supported from National Science Foundation (NSF) grants AST-0407380, AST-0909073 and AST-1313370. The American Association of Variable Star Observers has been helpful for finder charts, comparison star magnitudes and recruiting skilled observers, including S. Dufoer, K. Menzies, R. Sabo, G. Stone, R. Tomlin and G. Walker. These results are based on observations obtained with the HPF on the Hobby–Eberly Telescope (HET), which is named in honour of its principal benefactors, William P. Hobby and Robert E. Eberly. These data were obtained during HPF’s engineering and commissioning period. We thank the resident astronomers and telescope operators at the HET for the execution of our observations with HPF. We thank C. Cañas for providing an independent verification of the HPF SERVAL pipeline using a CCF-based method to calculate the radial velocities, which resulted in fully consistent radial velocities to the SERVAL-based radial velocities presented here. The HET is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universität München and Georg-August Universität Gottingen. The HET collaboration acknowledges support and resources from the Texas Advanced Computing Center. This work was partially supported by funding from the Center for Exoplanets and Habitable Worlds, which is supported by the Pennsylvania State University, the Eberly College of Science and the Pennsylvania Space Grant Consortium. We thank A. Gil de Paz for obtaining the narrow-band-filter Hα imagery, J. Johnson for commissioning TYC 2597-735-1 radial velocity measurements as part of the California Planet Finder programme, and A. Howard for leading Keck–HIRES spectra and performing the primary radial-velocity reduction on all HIRES data. K.H. acknowledges support from a David and Ellen Lee Postdoctoral Fellowship in Experimental Physics at Caltech, and thanks L. Hillenbrand and E. Hamden for discussions about aspects of this work. B.D.M. acknowledges support from the Hubble Space Telescope (number HST-AR-15041.001-A) and the NSF (number 80NSSC18K1708). K.J.S. received support from the NASA Astrophysics Theory Program (NNX17AG28G). G.S. and A.Mo. acknowledge support from NSF grants AST-1006676, AST-1126413, AST-1310885, AST-1517592, AST-1310875 and AST-1907622, the NASA Astrobiology Institute (NNA09DA76A) and PSARC in their pursuit of precision radial velocities in the near-infrared with HPF. We acknowledge support from the Heising-Simons Foundation via grant 2017-0494 and 2019-1177. Computations for this research were performed on the Pennsylvania State University’s Institute for Computational and Data Sciences. G.S. acknowledges support by NASA HQ under the NASA Earth and Space Science Fellowship Program through grant NNX16AO28H, and is a Henry Norris Russell Fellow.
Publisher Copyright:
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2020/11/19
Y1 - 2020/11/19
N2 - Stellar mergers are a brief but common phase in the evolution of binary star systems1,2. These events have many astrophysical implications; for example, they may lead to the creation of atypical stars (such as magnetic stars3, blue stragglers4 and rapid rotators5), they play an important part in our interpretation of stellar populations6 and they represent formation channels of compact-object mergers7. Although a handful of stellar mergers have been observed directly8,9, the central remnants of these events were shrouded by an opaque shell of dust and molecules10, making it impossible to observe their final state (for example, as a single merged star or a tighter, surviving binary11). Here we report observations of an unusual, ring-shaped ultraviolet (‘blue’) nebula and the star at its centre, TYC 2597-735-1. The nebula has two opposing fronts, suggesting a bipolar outflow of material from TYC 2597-735-1. The spectrum of TYC 2597-735-1 and its proximity to the Galactic plane suggest that it is an old star, yet it has abnormally low surface gravity and a detectable long-term luminosity decay, which is uncharacteristic for its evolutionary stage. TYC 2597-735-1 also exhibits Hα emission, radial-velocity variations, enhanced ultraviolet radiation and excess infrared emission—signatures of dusty circumstellar disks12, stellar activity13 and accretion14. Combined with stellar evolution models, the observations suggest that TYC 2597-735-1 merged with a lower-mass companion several thousand years ago. TYC 2597-735-1 provides a look at an unobstructed stellar merger at an evolutionary stage between its dynamic onset and the theorized final equilibrium state, enabling the direct study of the merging process.
AB - Stellar mergers are a brief but common phase in the evolution of binary star systems1,2. These events have many astrophysical implications; for example, they may lead to the creation of atypical stars (such as magnetic stars3, blue stragglers4 and rapid rotators5), they play an important part in our interpretation of stellar populations6 and they represent formation channels of compact-object mergers7. Although a handful of stellar mergers have been observed directly8,9, the central remnants of these events were shrouded by an opaque shell of dust and molecules10, making it impossible to observe their final state (for example, as a single merged star or a tighter, surviving binary11). Here we report observations of an unusual, ring-shaped ultraviolet (‘blue’) nebula and the star at its centre, TYC 2597-735-1. The nebula has two opposing fronts, suggesting a bipolar outflow of material from TYC 2597-735-1. The spectrum of TYC 2597-735-1 and its proximity to the Galactic plane suggest that it is an old star, yet it has abnormally low surface gravity and a detectable long-term luminosity decay, which is uncharacteristic for its evolutionary stage. TYC 2597-735-1 also exhibits Hα emission, radial-velocity variations, enhanced ultraviolet radiation and excess infrared emission—signatures of dusty circumstellar disks12, stellar activity13 and accretion14. Combined with stellar evolution models, the observations suggest that TYC 2597-735-1 merged with a lower-mass companion several thousand years ago. TYC 2597-735-1 provides a look at an unobstructed stellar merger at an evolutionary stage between its dynamic onset and the theorized final equilibrium state, enabling the direct study of the merging process.
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UR - http://www.scopus.com/inward/citedby.url?scp=85091760565&partnerID=8YFLogxK
U2 - 10.1038/s41586-020-2893-5
DO - 10.1038/s41586-020-2893-5
M3 - Article
C2 - 33208957
AN - SCOPUS:85091760565
SN - 0028-0836
VL - 587
SP - 387
EP - 391
JO - Nature
JF - Nature
IS - 7834
ER -