måndag 21 mars 2011

Our Sun Twin?

Anna Önehag from Sweden, and her team has found our solar twin? Unlike our Sun the twin belongs to Messier 67 group. It may be that our Sun was born in M67 4,5 bilj. years ago, but has wandered away reports Populär Astronomi.

M67-1194, an unusually Sun-like solar twin in M67

Anna Önehag (t h) and Andreas Korn.

New video of a Sun burst.

Results. We find M67-1194 to have stellar parameters indistinguishable from the solar values, with the exception of the overall metallicity which is slightly super-solar ([Fe/H] = 0.023 ± 0.015). An age determination based on evolutionary tracks yields 4.2 ± 1.6 Gyr. Most surprisingly, we find the chemical abundance pattern to closely resemble the solar one, in contrast to most known solar twins in the solar neighbourhood.

Conclusions. We confirm the solar-twin nature of M67-1194, the first solar twin known to belong to a stellar association. This fact allows us to put some constraints on the physical reasons for the seemingly systematic departure of M67-1194 and the Sun from most known solar twins regarding chemical composition. We find that radiative dust cleansing by nearby luminous stars may be the explanation for the peculiar composition of both the Sun and M67-1194, but alternative explanations are also possible. The chemical similarity between the Sun and M67-1194 also suggests that the Sun once formed in a cluster like M67.

So we are entangled!

7 kommentarer:

  1. We explore the relationship between young, embedded binaries and their parent cores, using observations within the Perseus Molecular Cloud. We combine recently published Very Large Array observations of young stars with core properties obtained from Submillimetre Common-User Bolometer Array 2 observations at 850 μm. Most embedded binary systems are found towards the centres of their parent cores, although several systems have components closer to the core edge. Wide binaries, defined as those systems with physical separations greater than 500 au, show a tendency to be aligned with the long axes of their parent cores, whereas tight binaries show no preferred orientation. We test a number of simple, evolutionary models to account for the observed populations of Class 0 and I sources, both single and binary. In the model that best explains the observations, all stars form initially as wide binaries. These binaries either break up into separate stars or else shrink into tighter orbits. Under the assumption that both stars remain embedded following binary break-up, we find a total star formation rate of 168 Myr−1. Alternatively, one star may be ejected from the dense core due to binary break-up. This latter assumption results in a star formation rate of 247 Myr−1. Both production rates are in satisfactory agreement with current estimates from other studies of Perseus. Future observations should be able to distinguish between these two possibilities. If our model continues to provide a good fit to other star-forming regions, then the mass fraction of dense cores that becomes stars is double what is currently believed.

  2. A wide binary companion to our sun would have been 17 times farther from the sun than its most distant planet today, Neptune.

    Based on this model, the sun’s sibling most likely escaped and mixed with all the other stars in our region of the Milky Way galaxy

  3. https://www.sciencedaily.com/releases/2017/06/170614091907.htm

  4. https://en.wikipedia.org/wiki/Binary_star

  5. http://matpitka.blogspot.com/2017/06/why-should-stars-be-borne-in-pairs.html

  6. https://arxiv.org/abs/1009.4579
    The chemical similarity between the Sun and M67-1194 also suggests that the Sun once formed in a cluster like M67.

  7. https://arxiv.org/abs/1409.1193