HD 73526 is a G6 star (i.e., a solar-like main sequence dwarf) that has just made some interesting news. As Greg Laughlin writes in a new posting on his Systemic site, Paul Butler, Geoff Marcy, Chris Tinney and collaborators with the Anglo-Australian Planet Search Project have found that the planetary system around the star displays an unusual resonance whose motion over time can be viewed in this online mpeg file. But even more striking is the nature of the two gas giant planets found here. The inner (HD 73526b) orbits with a 188 day period, while the outer has a period of 379 days. Let Laughlin tell it:
Planet c is a true room temperature gas giant. Liquid water likely blows in gusty sheets across its cloudy skies. (And it’s worth noting that any large moons circling HD 73526 c lie pleasantly within the stellar habitable zone.)
Got that? Centauri Dreams yields to no one when it comes to fascination over exoplanetary orbits, particularly unusual resonances between distant worlds, but Laughlin is talking about moons that, if they exist, are clearly in the habitable zone of this star. Of course, we don’t know whether, planet c has moons or not, but it is some comfort to realize just how many satellites we’ve found around the gas giants in our own system. And the vision of life coming into existence and evolving in such a setting remains breathtaking, even in a time when exoplanetary discoveries are coming in almost too fast to catalog.
The paper, accepted by the Astrophysical Journal, is Tinney, Butler, Marcy et al., “The 2:1 resonant exoplanetary system orbiting HD73526,” with an abstract now available.