Theo Marlow

HAT-P-41 b: The Jupiter That Outgrew Jupiter Jupiter is the one planet most of us have actually seen for ourselves, a pale, striped dot through a cheap pair of binoculars. About 1,101 light-years away there’s a planet built the same way, but swollen to roughly twice Jupiter’s width. It’s called HAT-P-41 b, and it’s a … Read more

A Planet on a Stretched-Out Loop An orbital eccentricity of 0.92, more than triple the most stretched planet our own solar system has to offer, belongs to a world called HD 26161 b. Eccentricity is a shape number, not a distance or a speed: zero means a perfect circle, and numbers creeping toward one describe … Read more

Kepler-435 b: Twice Jupiter’s Width, Thinner Than Scuba Tank Air Picture Jupiter, the planet big enough to swallow a thousand Earths, then double its width. That doubled giant is Kepler-435 b: a planet with a radius of roughly 88,400 miles (142,300 km), about 22.3 times Earth’s own radius of 3,959 miles (6,371 km). Here’s where … Read more

A Wheel Pulled Into a Sliver Take a bicycle wheel, perfectly round, and pull on opposite sides of the rim until it looks less like a circle and more like a long, narrow oval. Somewhere around a star roughly 278 light-years away, a planet several times more massive than Jupiter traces exactly that kind of … Read more

A Gas Giant Roughly Twice Jupiter’s Size, Built Like Foam Start with Jupiter, the banded giant on every solar-system poster, then stretch it, with a caveat attached. HIP 65 A b, a planet orbiting a small, orange-tinted star called HIP 65 A, has an estimated radius of about 90,160 miles (145,100 km), roughly twice Jupiter’s … Read more

Kepler-49 e: Checking a Number That Didn’t Add Up A density figure has been circulating for a planet orbiting another star: something like a hundredth of Earth’s own heft, light enough to beat packing foam. Run the actual catalog numbers for that planet, mass and radius, both on file with NASA, and the figure doesn’t … Read more

A Planet That Can’t Sit Still Picture a planet that packs into ten days what Earth spreads across an entire year: swinging in close enough to scorch, then flung back out far enough to freeze, every single lap, with no gentler orbit to fall back on. That planet has a name: GJ 3222 b, orbiting … Read more

WASP-33 b: A Dayside Edging Toward Tungsten’s Melting Point Picture the filament inside an old incandescent bulb, the one piece of metal that can glow white-hot for years without melting. Now imagine a whole planet’s daytime side closing in on that same temperature. WASP-33 b’s dayside carries an estimated 4,547 °F (2,781.7 K; 2,508 °C), … Read more

A Planet on a Rubber Band, Not a Wedding Ring Picture a planet swinging on a stretched-out ellipse instead of a tidy loop, flinging itself far from its star and then whipping back in, lap after lap. HIP 66074 b does exactly that, and the shape of that path has a number attached to it: … Read more

HD 80606 b: An Orbit Stretched Almost to Breaking Here’s the number first: 0.932. That’s orbital eccentricity, a scale from 0 (a perfect circle) to 1 (an ellipse squashed almost flat), and it’s the figure NASA’s Exoplanet Archive currently lists for HD 80606 b. Mercury, the most elongated orbit in our own solar system, sits … Read more