Test 10 – Does Sirius C exists
We should not be surprised if it does. To quote a conservative source, the Harvard Bright Star Catalog:
"C, companion to B at 1.4" suspected but not confirmed"
It says this sort of thing for a thousand stars where the suspicion is probably correct.
One support for the existence of Sirius C is as an explanation for the historical "Red Sirius."
Bonnet Bidaud and Gray say:
If Sirius is a typical hierarchial system in which a low-mass star is in a wide eccentric orbit around the inner A-B binary, the periodical irruption of this low mass (and therefore yet undetected) companion inside the inner binary would cause enough matter to be expelled to produce the observed reddening. To test this hypothesis, we undertook optical observation to search for this companion.
After Sirius B was discovered in 1867 (see test 2), the following statement is relevant.
As soon as 1894, irregularities were found in the motion of Sirius B, and lead one to suspect the existence of a third body in the system. Moreover, observations, mainly in the 1920’s, and reflexions on physics of Sirius A, came and supported this hypothesis. But this is still controversial, as we will see below (for more historical details about this section, see e.g. Allen 1963; Baize 1931, 1987, Benest 1987).
-- Benest and Duvent (see below)
Observations of Sirius C in the 1920s:
A tiny star has been observed about twenty times between 1920 and 1930. If there was a real object and not a “phantom” – the observers themselves were sometimes in doubt, an orbit of around 2 years could roughly agree. However, we still see that this period does not fit with the results of the orbital analysis.
-- Benest and Duvent (see below)
Details of the 1920s Observations:
"As for a third star, Phillip Fox reported in 1920 that the image of Sirius B had appeared to be double, using the same 18 1/2 inch refractor with which Clark discovered B. R.T. Innes in S. Africa and van den Bos, a renowned double-star observer, also reported the 3rd star. I should note here that these were visual studies, and the object in question is at the very limit of what can be observed with a telescope. "
This was the knowledge available in 1950. In 1973 I.W.Lindenblad of the U.S.Naval Observatory concluded that there was no astrometric evidence for a 3rd star, and this seemed to shut the case for a while, along with the authoritative statements of Sirius C skeptics Gatewood and Gatewood, who took detailed measurements of B.
However, the question is still taken seriously by professional astronomers, for other reasons, and in 1995 was published Is Sirius a Triple Star?, by D. Benest and J.L. Duvent, Astronomy and Astrophysics 299, 621-628 (1995). Their case is based on orbital analysis of A and B. Despite Lindenblad's observational failure, three independent mathematical methods with updated and more accurate orbital data show a perturbuation of 6.3 years which B&D hypothesize to be the orbital period of the third body, Sirius C.
This period may be searched through a study of variations of the aerial velocity; Zagar in 1932 used this method and found a period of 6.3 years, for a perturbing body around Sirius B; but we must note that this method requires several hypotheses so that the result depends on the chosen procedure (see Volet 1932). More simply, and more rigorously, the period of the perturbation can be obtained by a least square algorithm which Volet (1932) solve analytically. He proposed then the value of 6.4 years around Sirius B, but possibly also around Sirius A; more recently, one of us used an analogous algorithm for numerical computation and obtained a value around 6 years (this will be developed in Sect. 2). Finally, another possibility is simply to apply a Fourier analysis to detect the period of perturbation.
We have therefore three independent methods giving rather close values; we think then that this is a rather strong indication in favor of the reality of the perturbation.
2.4 Concluding the orbital analysis
Process enhancements, more data sued and two new methods confirm the previous studies that 6.3 years period perturbation probably exists in Sirius A-B orbit. More accuracy shows that the perturbation amplitude is 0.055”; as we know Sirius’ parallax A mass and B mass, we can estimate C mass and distance from its primary, which, as shown in the next section is very likely Sirius A.
They say it must be a red/brown dwarf of 0.05 Mo, and offer suggestions to observe it in the infra-red spectrum "within 3" of Sirius A."
By the way, this fascinating paper is available at the fantastic NASA Astrophysics Data System and its many mirrors.
In the paper about Red Sirius, Bonnet-Bidaud & Gray make an observation of Sirius' stellar field by masking the great brightness of Sirius A.
They come up with several candidate objects for Sirius C.
We note that no star brighter than an apparent magnitude of Mv >14 (absolute magnitude Mv, > 17 at Sirius distance) is seen.
This excludes the possibility of a companion more massive than 0.1 Mv and indicates that a Sirius companion, if any, would have to be close to the lower mass limit (about 0.08 Mo)
At which stellar configurations are able to sustain thermonuclear reactions.
Unfortunately, these objects on either side of the mass limit are not well known and their identification is therefore uncertain (see Kafatos et al. 1986). They are however very red; thus among the nine brightest objects in our sample the best candidates that appear to belong to the Sirius system are the 2 stars which appear to be redder than M8 type stars, namely star 4, with Mv around 20, B-V = 3.0 and V-I = 2.8, and marginally star 3, with Mv = 19.2, B-V = 2.0 and V-I = 2.5. Their distance from Sirius are 76” for star 4 and 60” for star 3, which implies, since the system is 2.7 pc away, projected distances of respectively 205 and 165 AU.
Bonnet-Bidaud 7 Gray (1993) have observed the vicinity of Sirius and proposed several faint stars (Mv about 17) as candidates, but they are all so far from Sirius B that they could actually be only remote companions of the system (see also Bonnet-Bidaud & Gray 1992)
There is also an amount of indirect collateral evidence for Sirius C. Red dwarfs are a common class of star but generally small and faint, and hard to observe.
Hence the surprise at the 1997 discovery that one was rather close by:
(Follows the NASA ADS abstract from The Solar Neighborhood, IV: Discovery of the Twentieth nearest Star System
HENRY, TODD J.; IANNA, PHILIP A.; KIRKPATRICK, J. DAVY; JAHREISS, HARTMUT
Astronomical Journal v.114, p. 388-395 (07/1997)):
"As part of a RECONS (Research Consortium on Nearby Stars) effort to discover stars nearer than 10 parsecs, LHS 1565 (GJ 1061; V = 13.03; M5.5 V) has been found to be only 3.7 parsecs from the Sun using a combination of photometric, spectroscopic and trigonometric parallax work. It ranks as the twentieth closest stellar system and underscores the incompleteness of the nearby star sample, particularly for objects near the end of the main sequence.
Ironically, this unassuming red dwarf provides a shocking reminder of how much we have yet to learn about even our nearest stellar neighbours."
For instance, another pioneering result of "seeing the faint" occurred in 1994 with discovery of Gliese 623B.
PHOTO RELEASE NO.: STScI-PRC94-54
RELEASE DATE: DECEMBER 21, 1994
HUBBLE FINDS ONE OF THE SMALLEST STARS IN THE UNIVERSE
This NASA Hubble Space Telescope picture resolves, for the first time, one of the smallest stars in our Milky Way Galaxy. Called Gliese 623b or Gl623b, the diminutive star (right of center) is ten times less massive than the Sun and 60,000 times fainter. (If it were as far away as the Sun, it would be only eight times brighter than the full Moon).
Located 25 light-years away in the constellation Hercules, Gl623b is the smaller component of a double star system, where the separation between the two members is only twice the distance between Earth and the Sun (approximately 200 million miles). The small star completes one orbit about its larger companion every four years.
Test 11 - Sirius C has "rays" (flares?).
The Dogon say that emme ya "also emits rays which have the quality of solar rays" and give these rays as the symbol.
For a star that “might not exist” we have hard numbers for mass, size, orbit and even an idea of its internal structure.
It has been hypothesised that Sirius C became visible in the 1920s because of flaring (the observations do not match Benest and Duvent's orbital data, see above). Red dwarf flaring was discovered on October 12, 1994 by a team led by Dr. Jeffrey Linsky at the Joint Institute for Laboratory Astrophysics (JILA) in Boulder, Colorado, in another observation of faint objects with the Hubble Space Telescope.
The star Gliese 752B (VB10) and its companion star Gliese 752A make up a binary system located 19 light-years away in the constellation Aquila. Gliese 752A is a red dwarf that is one-third the mass of the Sun and slightly more than half its diameter. By contrast, Gliese 752B is physically smaller than the planet Jupiter and only about nine percent the mass of our Sun. This very faint star is near the threshold of the lowest possible mass for a true star (0.08 Mo), below which nuclear fusion processes cannot take place according to current models, and "brown dwarf" stars result.
Using Hubble's Goddard High Resolution Spectrograph (GHRS) to look for solar flares as occur on our own sun, there was surprise that while the larger red dwarf was flaring as predicted, tiny Gliese 752B, 0.08 Mo, normal temperature 4,500 degrees F, also produced a flare of 270,000 degrees F, despite not having a radiative core, meaning that it must have a strong magnetic field or "dynamo." Hence Sirius C, a star said to be of similar size, could also flare.
Test 12 - Sirius C is bigger but four times lighter than Sirius B.
Benest and Duvent say the star's mass is a maximum of 0.05Mo, rather less than the Dogon figure of 0.2585Mo. (Taking Sirius B = 1.034Mo)
Nevertheless, the mass of Sirius C is probably low, otherwise the perturbations would destroy the binary very rapidly; we may roughly estimate the maximum value for Mc to be around 0.05 Mo (Sirius C would then be at best a red dwarf M5 with Mv around 12), which is much less than the masses of Sirius A and B respectively, 2.14 and 1.05 Mv.
And later on they add,
In this study we have supposed that the 6-year perturbation in the orbit of Sirius A-B is due to the presence of a third body in the System, i.e., Sirius C. Dynamical and astrophysical considerations lead to a very low mass for this suspected companion: a maximum of 0.05 Mo, i.e., a M5 to M5 star of absolute magnitude of 15 to 20. The visual magnitude of Sirius C could then be 5 to 10 more than that of the white dwarf Sirius B (mv = 8.5), itself 10 times more than that of Sirius A (mv – 1.5); therefore very difficult to observe.
As for size, if Sirius C:Sirius B = Jupiter:Earth, then the ratio of radius size is about 11. So Sirius C is bigger than Sirius B.
Test 13 - Sirius C has orbit of 50 (or 32*Renard Pale) years.
Benest and Duvent's figure for the orbit (which is ipso facto the proof of the star's existence) is a mathematically rigorous: 6.3 years. It’s rather less than either 50 years and even the revised figure of 32 years.
Although, with the reddening of Sirius still in mind, Bonnet-Bidaud and Gray's quote below spells out the conditions for the reddening.
For interaction to occur, two conditions are required on the orbital elements of the third companion: a period P3 longer than about 2000 years (the last interaction) and an approach distance (d) to the inner A-B binary of the same order than the average Sirius A-B separation, i.e., 20 AU.
Test 14-15: Sirius C has a "larger" orbit than Sirius B; Sirius C orbit is at right angles to that of Sirius B.
USSS saying Sirius C has a "larger" orbit than Sirius B has been interpreted as meaning an orbit more circular than elliptical. In this discussion Benest and Duvent cite astronomers J.R.Donnison and I. P. Williams, who had calculated the hypothetical possibility of a stable three-body arrangement in the specific Sirius system in 1978.
Do stable orbits exist around Sirius and/or Sirius B with a period of 6 years? Do stable orbits exist far around Sirius A-B which could perturb (for example through a resonance) the orbits of Sirius A and B around each other, again with a period of 6 years? The latter has been explored by, e.g., Donnison & Williams (1978).
Early into my quest, Donnison and Williams had been quoted in the popular paranormal literature by Karl Shuker as supports for the Dogon contentions and I emailed them about this. Dr. Iwan P. Williams was gracious enough to send me this email in response:
“At the time (as indeed now) there was a lot of interest in planets around other stars; and the paper mentioned really has to be seen within that context. We had written a number of papers enquiring about the stability of hypothetical systems and a relevant question was whether "planets" could exist within a binary star context. The Dogon thing came out about that time, and it seemed appropriate to ask the same question about Sirius as for a general system, i.e., could we have a planet in particular given binary system, i.e., Sirius. the answer is not that remarkable; yes, provided it is far enough away from the binary pair that the changes in gravity is small and it can be closer on average on a circular orbit (mean distance = minimum distance)".
Tests 16-18: Sirius C has one main planet in orbit; orbit of main planet is 30 years; Sirius C has two planets in orbit.
[LET'S WAIT FOR A NEW GENERATION OF INSTRUMENTS]
Meanwhile, if Sirius C really has a planet, an orbit of 30 years is surely an over-estimate.
Does true imagination = real facts?