# Massive Nearby Stars

Is there a possibility that I will find records of stars with masses around 25-30 solar masses within 30 parsecs of solar system. If not, how far do I need to look?

• just google "catalog of stars with mass". I got some interesting results on the first page. – Florin Andrei Jul 22 '15 at 21:13
• www-wfau.roe.ac.uk/vespa is a computed stellar mass database (see arxiv.org/pdf/0904.1001v2 for details) – user21 Jul 23 '15 at 1:42
• @barrycarter The VESPA catalogue contains galaxies ?? – Rob Jeffries Jul 23 '15 at 11:02

There aren't any.

A 25-30 $M_{\odot}$ main sequence star would have a spectral type of $\sim$ O7 and an absolute $V$ magnitude $M_V \simeq -5$ (see Zombeck 1982). A giant star with this mass would be even more luminous.

At a distance of 30pc, the apparent magnitude of such a star would be $V=-2.6$. Closer examples would of course be brighter. Sirius is the brightest star in the sky with $V=-1.46$.

The nearest O-star may be zeta Ophiuchus which is at about 450 light years (or about 140 parsecs). This might be a bit lower than $25M_{\odot}$. Betelgeuse, a red supergiant at a Hipparcos-measured distance of $152\pm 20$ pc, probably has a mass of about $15 M_{\odot}$, but I think this is quite uncertain.

The secondary of $\gamma^{2}$ Velorum has an O7.5V spectral type and reasonably well-determined mass of about $30M_{\odot}$ (Eldridge 2009) and a distance of $336 \pm 8$ pc (North et al. 2007).

Rob Jeffries nailed it, but I'll add a few points.

25-30 stellar mass stars are quite rare. O-type stars begin at a mass of about 16 suns and they're about 0.00003% of the main sequence (that's 1 in 3 million). They're also short lived, a few million to maybe 10 million years in main sequence. That's part of the reason there are so few of them.

If we look at what stars are near us - lets just go 20 light years, there's about 150 stars and star like objects - source: http://www.solstation.com/stars/s20ly.htm

Each time you double the distance, you have 8 times the volume, so within 100 light years (and this is a very rough estimate), 5 to the 3rd power * 150, roughly 20,000 stars within 100 light years of earth. So if a star of the size you're looking for is 1 in 3 million (or less common than that at 25-30 solar masses), and there's 20,000 stars within 100 light-years, it's not surprising that there's none that close to earth. That doesn't mean there's never been one that close, cause star orbits in the Milky way move around in relation to each other quite a bit over time, but mostly stars of that size don't get that close cause they're very rare.

Loosely related footnote, but SN 1054, which is now the Crab Nebula was so bright when it went super nova that it could be seen during the day (for about 23 days) and that's 6,500 light years away. We can see stars that large well over 100 light years. Betelgeuse is 640 light years away and it's the 8th brightest star in the sky. They don't have to be that close to be impressive.