Planets orbiting two stars have been found, but not all that many of them. We’re talking here about a planet that orbits both stars of a close binary system, and thus far, although we’ve confirmed over 6,000 exoplanets, we’ve only found 14 of them in this configuration. Circumbinary planets are odd enough to make us question what it is we don’t know about their formation and evolution that accounts for this. Now a paper from researchers at UC-Berkeley and the American University of Beirut probes a mechanism Einstein would love. At play here are relativistic effects, having to do with the fact that, as Einstein explained, intense gravitational fields have detectable effects upon the stars’ orbits. This is hardly news, as it was the precession of Mercury in the sky that General Relativity first predicted. The planet’s orbit could be seen to precess (shift) by 43 arcseconds per century more than was expected by Newtonian mechanics. Einstein showed in 1915 that spacetime curvature could...

It’s been apparent for a long time that far more astronomical data exist than anyone has had time to examine thoroughly. That’s a reassuring thought, given the uses to which we can put these resources. Ponder such programs as Digital Access to a Sky Century at Harvard (DASCH), which draws on a trove of over half a million glass photographic plates dating back to 1885. The First and Second Palomar Sky Surveys (POSS-1 and POSS-2) go back to 1949 and are now part of the Digitized Sky Survey, which has digitized the original photographic plates. The Zwicky Transient Facility, incidentally, uses the same 48-inch Samuel Oschin Schmidt Telescope at Palomar that produced the original DSS data. There is, in short, plenty of archival material to work with for whatever purposes astronomers want to pursue. You may remember our lengthy discussion of the unusual star KIC 8462852 (Boyajian’s Star), in which data from DASCH were used to explore the dimming of the star over time, the source of...

Sometimes we forget how overloaded our observatories are, both in space and on the ground. Why not, for example, use the James Webb Space Telescope to dig even further into TRAPPIST-1’s seven planets, or examine that most tantalizing Earth-mass planet around Proxima Centauri? Myriad targets suggest themselves for an instrument like this. The problem is that priceless assets like JWST not only have other observational goals, but more tellingly, any space telescope is overbooked by scientists with approved observing programs. Add to this the problem of potentially misleading noise in our data. Thus the significance of Pandora, lofted into orbit via a SpaceX Falcon 9 on January 11, and now successful in returning robust signals to mission controllers. One way to take the heat off overburdened instruments is to create much smaller, highly specialized spacecraft that can serve as valuable adjuncts. With Pandora we have a platform that will monitor a host star in visible light while also...

I jump at the chance to see actual images – as opposed to light curves – of exoplanets. Thus recent news of a Tatooine-style planetary orbit around twin stars, and what is as far as I know the first actually imaged planet in this orbital configuration. I’m reminded not for the first time of the virtues of the Gemini Planet Imager, so deft at masking starlight to catch a few photons from a young planet. Youth is always a virtue when it comes to this kind of thing, because young planets are still hot and hence more visible in the infrared. The Gemini instrument is a multitasker, using adaptive optics as well as a coronagraph to work this magic. The new image comes out of an interesting exercise, which is to revisit older GPI data (2016-2019) at a time when the instrument is being upgraded and in the process of being moved to Hawaii from Chile, for installation on the Gemini North telescope on Mauna Kea. This reconsideration picked out something that had been missed. Cross-referencing...

Let’s have a look at recent work on TRAPPIST-1. The system, tiny but rich in planets (seven transits!) continues to draw new work, and it’s easy to see why. Found in Aquarius some 40 light years from Earth, a star not much larger than Jupiter is close enough for the James Webb Space Telescope to probe the system for planetary atmospheres. Or so an international team working on the problem believes, with interesting but frustratingly inconclusive results. As we’ll see, though, that’s the nature of this work, and in general of investigations of terrestrial-class planet atmospheres. I begin with news of TRAPPIST-1’s flare activity. One of the reasons to question the likelihood of life around small red stars is that they are prone to violent flares, particularly in their youth. Planets in the habitable zone, and there are three here, would be bathed in radiation early on, conceivably stripping their atmospheres entirely, and certainly raising doubts about potential life on the surface....

I’ve been thinking about how useful objects in our own Solar System are when we compare them to other stellar systems. Our situation has its idiosyncrasies and certainly does not represent a standard way for planetary systems to form. But we can learn a lot about what is happening at places like Beta Pictoris by studying what we can work out about the Sun’s protoplanetary disk and the factors that shaped it. Illumination can come about in both directions. Think about that famous Voyager photograph of Earth, now the subject of an interesting new book by Jon Willis called The Pale Blue Data Point (Princeton, 2025). I’m working on this one and am not yet ready to review it, but when I do I’ll surely be discussing how the best we can do at studying a living terrestrial planet at a considerable distance is our own planet from 6 billion kilometers. We’ll use studies of the pale blue dot to inform our work with new instrumentation as we begin to resolve planets of the terrestrial kind. But...

I have a number of things to say about Teegarden’s Star and its three interesting planets, but I want to start with the discovery of the star itself. Here we have a case of a star just 0.08 percent as massive as the Sun, an object which is all but in brown dwarf range and thus housing temperatures low enough to explain why, despite its proximity, it took until 2003 to find it. Moreover, conventional telescopes were not the tools of discovery but archival data. Bonnard Teegarden (NASA GSFC) dug into archival data from the Near-Earth Asteroid Tracking program, surmising that there ought to be more small stars near us than we were currently seeing. The data mining paid off, and then paid off again when the team looked at the Palomar Sky Survey of 1951. This was a team working without professional astronomers and telescopes. Image: Teegarden's Star was subsequently identified in astronomical images taken more than 50 years ago. Credit: Palomar Sky Survey / SolStation.com. That it took...