NASA’s NICER Sizes Up a Pulsar, Reveals First-ever Surface Map

Watch how NASA’s Neutron star Interior Composition Explorer (NICER) has expanded our understanding of pulsars, the dense, spinning corpses of exploded stars. Pulsar J0030+0451 (J0030 for short), located 1,100 light-years away in the constellation Pisces, now has the most precise and reliable measurements of both a pulsar’s mass and size to date. The shapes and locations of its hot spots challenge textbook depictions of these incredible objects.

Music: "Uncertain Ahead" and "Flowing Cityscape" (underscore). Both from Universal Production Music

Credit: NASA's Goddard Space Flight Center

Watch this video on the NASA Goddard YouTube channel.

Complete transcript available.

One team, led by researchers at the University of Amsterdam, determined J0030 is 1.3 times the Sun’s mass, 15.8 (25.4 kilometers) across and has two spots — one small and circular and the other long and crescent-shaped. This visualization shows J0030 from its equator, 90 degrees from the spin axis.

Credit: NASA’s Goddard Space Flight Center/CI Lab

The spot-and-crescent J0030 visualization, shown 144 degrees from the spin axis for a clear view of the hot spots.

Credit: NASA’s Goddard Space Flight Center/CI Lab

The Amsterdam-led team determined that NICER’s line of sight onto the pulsar is 54 degrees from the spin axis, as shown in this wireframe animation. The pulsar is so dense its gravity warps nearby space-time — the “fabric” of the universe as described by Einstein’s general theory of relativity. Space-time is so distorted that light from the side of the pulsar facing away from us is “bent” and redirected into our view, shown by the warped gridlines. This makes the star look bigger than it really is.

Credit: NASA’s Goddard Space Flight Center

This wireframe shows the spot-and-crescent model from J0030’s equator.

Credit: NASA’s Goddard Space Flight Center

A wireframe of the spot-and-crescent J0030 model, seen 144 degrees from the spin axis.

Credit: NASA’s Goddard Space Flight Center

Another team, led by a researcher at the University of Maryland, found that J0030 is 1.4 times the Sun’s mass, about 16.2 miles (26 kilometers) wide and has two or three oval hot spots. This visualization shows the three-oval model from the equator, 90 degrees from the spin axis.

Credit: NASA’s Goddard Space Flight Center/CI Lab

The three-oval J0030 visualization, show 144 degrees from the spin axis.

Credit: NASA’s Goddard Space Flight Center/CI Lab

The Maryland-led team calculated that NICER views J0030 58 degrees from its spin axis, as shown in this wireframe. The two teams determined slightly different viewing angles based on their independent modeling methods.

Credit: NASA’s Goddard Space Flight Center

This wireframe shows the three-oval J0030 model from the equator.

Credit: NASA’s Goddard Space Flight Center

This wireframe shows the three-oval J0030 model, 144 degrees from the spin axis.

Credit: NASA’s Goddard Space Flight Center

This visualization shows the spot-and-crescent and three-oval models side by side. J0030 challenges the traditional textbook image of pulsars. Scientists are still trying to understand what caused the shape and arrangement of its hot spots.

Credit: NASA’s Goddard Space Flight Center/CI Lab

NICER is an X-ray telescope aboard the International Space Station.

Credit: NASA

Simulation of a possible quadrupole magnetic field configuration for a pulsar with hot spots in the only the southern hemisphere.

Credit: NASA's Goddard Space Flight Center