- A quintuple system at ξ Sco.
Starting up default Celestia, one notices that the Galaxy is populated by almost entirely single-star systems. But each star is a place, and each place is likely to be more than just a single star -- whether it has planets or additional stellar components. I've been putting a lot of effort into tracking the discovery of planets and maintaining a catalogue of them here. That leaves the other half of the equation -- multi-stellar systems. There's an innumerable number of them known. I don't think I could conceivably produce an .stc file with all of them, and certainly not maintain it as research comes out. So I'm not going to try. But I do think it would be worthwhile to have a decent catalogue of them.
Celestia already has multi-star system files -- spectbins.stc and visualbins.stc. But these contain just a few hundred systems. There are new sources of information since Celestia first came out that can be used. The Ninth Spectroscopic Binary Catalogue is a great source of about 4000 binary orbits, and several years ago I began a project to build an add-on for it. But many of these systems have additional stellar components with visual orbits in the Sixth Orbits Catalogue... so the project eventually grew to adding those as well.
At some point it became useful to keep track of eclipsing binary stars for the purpose of identifying false positives among reported TESS planet candidate systems. This has been so beneficial to my work that adding eclipsing binary stars has become something of a part-time hobby. Though again, I could never hope to have all of them.
There's some wide-binary systems that lack orbits, often because the system was in the exoplanet catalogue as a planet host candidate + distant companion, but then when that planet candidate was refuted, I'm left with the content for a binary system that may not be that interesting in itself. It is compiled using the same programme as the exoplanet catalogue. I didn't see the value of removing the knowledge from my notes so it has been left there, and hence remains in this add-on.
Not all of the systems in here are "up to date" in the literature. A cursory glance through the Multiple Star Catalog will show some of these systems have more components than is shown. In these cases, the components are not present in SB9 or Orb6. I thought about thoroughly going through the MSC and adding what I can of it, but I've had some difficulties finding references for some orbits and I've kinda gotten to the point where I'm a little tired of such massive work, at least for now.
I will probably continue to add to this as time goes on, and post updates to it accordingly. I am not interested in maintaining the orbits in this catalogue to the most recent literature values (I have only so much time), and so this catalogue should be seen as imbalanced in favor of having a large number of systems at the expense of the average quality per system. I have also elected to skip some systems that were dim and distant, having a bias toward nearby and/or bright stars.
Several systems in here are contact binaries. So there will be some conflict with the wonderful W UMa addon provided by A. J. Tribick. Finding a way to fix this incompatibility is something I may explore in the future.
For stars in visualbins.stc, I have chosen not to replace these systems if there is no additional stellar component. However in some cases, additional problems have appeared due to what seem to be limitations in Celestia's code. Some stars in visualbins.stc are missing their prefixes, but you can't use "Replace" with them while defining prefixes. I thought I could get around this by simply foregoing the prefixes in an .stc aimed at updating them, but for the system V640 Cas, the B component (now known to be a spectroscopic binary) corresponds to a star that's already defined as "TYC 3664-1986-2" due to what appears to be a failed cross-reference. It would be really nice to be able to
Code: Select all
Replace Barycenter 2019863664 "V640 Cas B"
- The famous telescope-accessible Albireo.
Sources
As a result of these efforts over the last several years, I've amassed a rather large addon for multi-stellar systems. While it has made use of large catalogues, it is extremely heterogeneous. If a paper appears on arXiv detailing some new multi-stellar system and I decide to throw it into my notes, it ends up here.
I've made use of information from
SB9: The Ninth Catalgue of Spectroscopic Binary Orbits,
Sixth Catalogue of Orbits of Visual Binary Stars,
Milky Way detached double-lined EB catalog,
KELT Follow-up Network and Transit False-Positive Catalog,
Comparative Statistics and Origin of Triple and Quadruple Stars,
A catalogue of parameters for eclipsing binaries,
The Value-Added Catalog of ASAS-SN Eclipsing Binaries III: Masses and Radii of Gaia Spectroscopic Binaries,
The Catalogue of Stellar Parameters from the Detached Double-Lined Eclipsing Binaries in the Milky Way,
Binary Masses and Luminosities with Gaia DR3,
Multiple Star Catalogue
Orbit alignment in triple stars (Tokovinin, 2017)
While Gaia DR3 NSS could potentially furnish an ungodly number of systems to this effort, there's some difficulties involved. Some of the astrometric orbits suffer, apparently, from poor discrimination between eccentric orbits vs highly inclined orbits. The spectroscopic binary list also has various issues, as I've learned cross-matching it with TESS candidates -- Gaia RV periods are often aliases, or worse. As a result, I've decided not to rely on unverified Gaia DR3 NSS solutions for this project except as supplementary information if there is a clear match between the Gaia DR3 NSS entry and available knowledge of the system.
Screenshots
- Eclipsing binary systems from transit searches.
- Spectroscopic binary systems in the SB9 catalogue.
Completeness
So one might ask - how complete is this? Obviously not very. But with nearer systems having an intrinsic bias among what we find interesting, it's still worth considering. I've used the Gaia 10 Parsec Sample to ensure that I have all multi-stellar systems within 10 parsecs. So plotting the number of systems in log-N vs log distance space, I get a graph that should be linear if the Universe is a uniformly distributed field of stars. Of course due to the shape of the Galaxy, this isn't the case.
I figured I would plot the systems in log distance, binned in groups of 0.1 log pc wide (so ten bins from 0 to 10 pc, another ten from 10 pc to 100 pc, etc). I'm reasonably confident I have every known system within ten parsecs here, but there's a lot of variation due to small number statistics in the number of systems per bin, which shows up in the graph. So that complicates the picture a bit. Quite a bit to my surprise, it's reasonably complete out to ~30 pc. I'm sure there's numerous stellar companions at the bottom of the main sequence (or below) that I am not aware of, and I'll add them if I come across them.
- Completeness graph.
Finally, there are efforts under way to create a 10 parsec version of nearstars.stc. While that is in development, I've made a "rough" supplement to the current nearstars.stc that includes the Gaia 10 Parsec Sample systems outside the ones already present in nearstars.stc. This file contains known single- and multi-stellar systems within 10 parsecs. As a result, the stars_binary.stc file posted here only has multi-stellar systems at distances greater than 10 parsecs. Users who would like to have a more complete immediate solar neighborhood can get that separate from a somewhat heavy .stc file that adds systems that they may not be interested in having. The stars_binary zip contains both files. Special thanks to Chara for collecting a lot of information that went into the 10 pc file as part of the aforementioned nearstars.stc efforts.
Total Stars: 20,368
