HR 1035 CAM (HR 1035 Camelopardalis). Camelopardalis, the Giraffe, browses quietly, surrounded to the south by bright Cassiopeia, Perseus, and Auriga, its pasture on the other side extending nearly to the North Celestial Pole. But you'd be a bit pressed to find it as the brightest star of the sprawling constellation is fourth magnitude (4.03) Beta Cam. The number two star, fourth magnitude (4.21) HR 1035 (the name from the Bright Star Catalogue) does not even have a Flamsteed number (which it ought), let alone a Greek letter (Alpha Cam ranks third, Gamma sixth). One would hardly recognize HR 1035 then as one of the great stars of the local Galaxy, a white class B9 bright supergiant and the brightest star of the Cam OB1 association of hot (O and B, and many others of lesser rank) stars, just a bit brighter than its constellation-mate and near-neighbor, HR 1040 Cam. The distance is so great as to be quite insecure, parallax making it 1940 light years away but with uncertainties that may take it as far as 2760 l-y or as close as 1500. Assuming the measure is not far from the mark, HR 1035 is among the nearest of the naked-eye members of the association. Just three degrees off the centerline of the Milky Way, distant HR 1035 is dimmed 1.3 magnitudes by interstellar dust. Were the pathway clear, the star would shine at the brighter end of third magnitude (2.90) and might even have a proper name.

HR1035 HR 1035 at left and HR 1040 at right are both related to dusty interstellar clouds that reflect or, more accurately, scatter their starlight. The scattering process is much more efficient toward shorter spectral wavelengths, which gives the "reflection nebulae" a bluish color, not seen here in this classic black and white photograph. North is to the left. (Palomer Sky Survey.)

Distance and temperature conspire to reveal a great luminosity of 29,900 Suns, from which we derive a radius of 48 times solar, more than 20 percent the size of Earth's orbit. With a projected equatorial rotation speed of 29.5 kilometers per second, the star could take as long as 80 days to make a full turn. HR 1035 could be in transit to becoming a red supergiant with a mass of 12 times that of the Sun and a dead helium core, or it could already have been a red supergiant, and with a mass of 11.5 Suns have come back to the white or blue supergiant phase to quietly fuse its internal helium into carbon and oxygen. It's hard to tell. Whatever the details, the star is only about 15 million years old and it looks as if it will blow up as a supernova even if it lies at the lower limit of distance and luminosity. As to other details, HR 1035 Cam varies by a few hundredths of a magnitude in a mode similar to that of Deneb, the result of pulsation and mass loss, and was thusly given the variable star name CS Cam. The star is related to a slight dusty cloud a quarter of a degree to the southeast that reflects its light. HR 1035 is also tracked by an eighth magnitude (7.8) companion that has maintained nearly the same separation over the past 180 years, so the two are most likely related. If so, the lesser one is a fine star in its own right, a B5 or so dwarf with a mass of around four times that of the Sun. Using the nominal distance of 1940 light years, the companion must be at least 1340 Astronomical Units away from the supergiant and take at least 13,000 years to orbit, far enough not to be directly affected by the coming explosion, though its orbit would be drastically altered, perhaps to the point of ejection.

Written byJim Kaler 1/30/15. Return to STARS.