DELTA PAV (Delta Pavonis). It's always fascinating to see among the stars one like the Sun, some kind of solar clone, and then wonder if there are any earths like ours. It's also fascinating to see one as bright as fourth magnitude (3.56, almost third), one prominent enough to be part of its constellation outline (Pavo, the Peacock), one deep in the southern hemisphere, the star but 24 degrees from the South Celestial Pole. Like the Sun it's a class G star, though cooler (G6-8, probably the latter), but unlike the Sun it's classed spectrally as a subgiant, which at first implies that it has just finished its career as a hydrogen-fusing dwarf or at least will soon. Of additional interest, it's not far from another star with solar similarities, Gamma Pavonis, an F6 dwarf. To be so visually bright for its class, the star has to be close to us, and at just 19.92 light years (with a probable error of only 0.02 light years) it most certainly is. Delta Pav's proximity also gives it a rapid motion across the sky relative to the background stars, a whopping (it's all relative) 1.66 seconds of arc per year, something that could be easily noted in a small telescope over a lifetime of observing. From that, the distance, and the velocity of 21.7 kilometers per second along the line of sight, we calculate a total velocity of 52.6 kilometers per second relative to the Sun, more than three times normal, suggesting that the star is a visitor from some other place in the Galaxy, one not on a fairly circular Galactic orbit as are we. With a surface temperature of 5548 Kelvin (vs. the Sun's 5780), Delta Pav is 26 percent more luminous than our own star, which gives it a radius of 1.22 times solar. Theory suggests a mass about that of the Sun, one study making it seven percent higher, which with possible advanced age would account for its higher luminosity. A projected equatorial rotation speed of but 1.0 kilometers per second gives it a rotation period that could be as long as 61 days (against the Sun's 25), also suggesting age (a solar type star slowing down with age as a result of magnetic activity coupled to its wind). The star has a metal content (relative to hydrogen) of around double that of the Sun, suggesting a visitation from the Galactic interior where metal contents run higher (as a result of more supernovae dumping their iron and whatnot into fertile stellar breeding grounds) and consistent with the high velocity. Being so close and so "solar," Delta Pavonis is a target for science fiction stories and tales of space aliens (see also Zeta Reticuli.) Alas, there is no evidence for planets, nor even any for dust excess or a debris disk that might marginally suggest planets. If there were anybody there, they would look back to see our Sun as a fourth magnitude (3.76) "clone" practically on our Ursa Major-Camelopardalis border, and might perhaps be wondering whether there is anybody here. (Thanks to Larry White, who suggested this star.)

Written byJim Kaler 5/30/14. Return to STARS.