Star profile
42 Herculis
Cool red starWhat is 42 Herculis
42 Herculis is an M-type red giant 414 light-years away, one of dozens of cool, swollen stars dotting the classical figure of Hercules. Its atmosphere barely reaches 3,500 degrees, hence that deep red that sets it apart from the youthful blues of neighbouring constellations. It shines this way because it has already crossed the final threshold of its evolution and ballooned its envelope to hundreds of solar diameters.
Where it is and when to see it
42 Herculis lies in the northern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is May, when it culminates around midnight.
- From London it never sets and culminates about 87° up.
- From New York it culminates about 82° above the horizon.
- From Sydney it culminates about 7° above the horizon.
It can be seen from anywhere north of 41° S.
It ranks no. 35 in brightness among the 136 stars of Hercules in our catalogue. To find it, start from Kornephoros, the brightest: it lies about 27° away (a fist at arm's length covers about 10°).
The light you see today left it about 410 years ago.
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Astronomical data for 42 Herculis
- Constellation
- Hercules
- Apparent magnitude
- 4.86
- Distance
- 414.5 light years
- Coordinates (J2000)
- RA 249.687° · Dec 48.928°
- Catalogue
- HIP 81497 · HD 150450
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Other stars in Hercules
Hercules has 136 stars in Stelvia's catalogue. Here are a few of them.
- KornephorosBeta Herculis2.78
- RasalgethiAlpha 1 Herculis2.78
- Zeta Herculis2.81
- 52 Herculis4.82
- 30 Herculis4.83
- 29 Herculis4.84
- 60 Herculis4.89
- 106 Herculis4.92