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astronomy – What are the demographics of stars seen to the bare eye?

astronomy – What are the demographics of stars seen to the bare eye?

2023-03-11 21:40:43

A lot of the brightest stars are close by important sequence stars with spectral varieties B, A and F (50%, e.g. Sirius, Altair, Vega), however there are additionally a bunch of extra distant O-type important sequence and big stars (5%, e.g. Regor, Naos) and one other huge clump of purple giants (about 35%, e.g. Arcturus, Aldebaran) and some % are distant supergiants (e.g. Deneb, Rigel, Betelgeuse). There are not any white dwarfs, and undoubtedly no neutron stars!

I’ve hooked up a picture which I created by deciding on 4992 brilliant (V<6, therefore seen from a superb web site) stars from the brand new, revised, Hipparcos catalogue (van Leeuwen 2007) with a parallax and plotted them on absolutely the V vs B-V colour-magnitude diagram (analogous to the Hertzsprung-Russell diagram). Additionally proven is a zero age important sequence for stars $<7M_{odot}$ from Siess et al. (2001).

I additionally present a histogram of their log10(distance) in parsecs. It is mainly lognormal with a peak at about 150pc. I am afraid mass will not be so easy – the Hipparcos catalogue may be discovered at when you fancy doing it your self

Really as a postscript, one factor we are able to say concerning the mass distribution is that when you have a look at the HR diagram you see that the majority the celebs are both (a) developed to develop into giants and subsequently will need to have lots $>0.9M_{odot}$ to have accomplished so throughout the time the Galaxy has existed or (b) are important sequence stars extra luminous than the Solar ($M_{V,odot} = 4.75$) and so should be extra large. So notably, all however a handful of stars seen to the bare eye are extra large than the Solar.

HR diagram of bright (V<6) stars in the Hipparcos catalogue
Histogram of distance for the sample.

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