Birbbirbbirb1

@birbbirbbirb1.bsky.social

Hello, I'm Birb! I love studying astronomy and myrmecology. [He]/him

@esa.intReposted by @birbbirbbirb1.bsky.social

Hera is approaching asteroid Didymos, where it will study the effects of NASA’s DART impact.

The initial braking manoeuvre has bee successfully completed, bringing Hera another step closer to its arrival in November.

Want to know more? Ask our Hera A Companion 👉 hera.esa.int

@astrochara.bsky.socialReposted by @birbbirbbirb1.bsky.social

Note that these use the D65 whitepoint, which is the standard, but ill-fit for space objects since it's intended for use under Earth's clear blue sky, and space doesn't have the clear blue sky.

@askaniy.bsky.social recalibrated the images to use Illuminant E, which is better.

More info in ALT!

A modified version of Figure B8 of the paper, where the whitepoint is changed from D65 to Illuminant E. The colour is shifted to be bluer relative to D65, which was orange-tinted. It shows simulations of white dwarfs with hydrogen-dominated atmospheres (DA) at 20000 K, 10000 K, and 7000 K respectively. These are hot blue ~blackbody stars, and limb darkening is barely visible for the hottest stars. As with every other image here, the left side contains spectra and limb darkening information, and the right side contains the generated image of the stars.A modified version of Figure B9 of the paper, where the whitepoint is changed from D65 to Illuminant E. The colour is shifted to be bluer relative to D65, which was orange-tinted. It shows simulations of three real white dwarfs with carbon-rich atmospheres (DQ). The topmost is pale blueish purplish, the middle is pink, and the bottom is orangish red.A modified version of Figure B10 of the paper, where the whitepoint is changed from D65 to Illuminant E. The colour is shifted to be bluer relative to D65, which was orange-tinted. It shows simulations of three real white dwarfs with metal-rich atmospheres (DZ). The topmost is cyanish white, the middle is pale greenish yellow, and the bottommost is pale lime green.A modified version of Figure B11 of the paper, where the whitepoint is changed from D65 to Illuminant E. The colour is shifted to be bluer relative to D65, which was orange-tinted. It shows simulations of three real white dwarfs with metal-rich atmospheres (DZ). The topmost is pale cyan, the middle is lime green, and the bottommost is deep sky blue, with strong limb darkening making it clearly distinct from hot DA stars.
Chara@astrochara.bsky.social

Section 4 details their visualization of these white dwarfs. Resolved stellar discs exhibits limb darkening, which affects the colour of the star as well. The results are presented in Figure B8-11.

Figure B8 of the paper. It shows simulations of white dwarfs with hydrogen-dominated atmospheres (DA) at 20000 K, 10000 K, and 7000 K respectively. These are hot blue ~blackbody stars, and limb darkening is barely visible for the hottest stars. As with every other image here, the left side contains spectra and limb darkening information, and the right side contains the generated image of the stars.Figure B9 of the paper. It shows simulations of three real white dwarfs with carbon-rich atmospheres (DQ). The topmost is pale purple, the middle is pink, and the bottom is orangish red.Figure B10 of the paper. It shows simulations of three real white dwarfs with metal-rich atmospheres (DZ). The topmost is white, the middle is pale yellow, and the bottommost is greenish yellow.Figure B11 of the paper. It shows simulations of three real white dwarfs with metal-rich atmospheres (DZ). The topmost is white, the middle is green, and the bottommost is very blue, with strong limb darkening.
@askaniy.bsky.socialReposted by @birbbirbbirb1.bsky.social

Yes, I can't recommend using D65 white point since its reference white is based on a clear sky environment, while in astronomy it's useful to compare with constant energy spectral distribution (illuminant E). D65 gives celestial bodies a consistent orange-pink hue. Result of the quick recalibration:

Photo, no descriptionPhoto, no description
@astrochara.bsky.socialReposted by @birbbirbbirb1.bsky.social

Section 4 details their visualization of these white dwarfs. Resolved stellar discs exhibits limb darkening, which affects the colour of the star as well. The results are presented in Figure B8-11.

Figure B8 of the paper. It shows simulations of white dwarfs with hydrogen-dominated atmospheres (DA) at 20000 K, 10000 K, and 7000 K respectively. These are hot blue ~blackbody stars, and limb darkening is barely visible for the hottest stars. As with every other image here, the left side contains spectra and limb darkening information, and the right side contains the generated image of the stars.Figure B9 of the paper. It shows simulations of three real white dwarfs with carbon-rich atmospheres (DQ). The topmost is pale purple, the middle is pink, and the bottom is orangish red.Figure B10 of the paper. It shows simulations of three real white dwarfs with metal-rich atmospheres (DZ). The topmost is white, the middle is pale yellow, and the bottommost is greenish yellow.Figure B11 of the paper. It shows simulations of three real white dwarfs with metal-rich atmospheres (DZ). The topmost is white, the middle is green, and the bottommost is very blue, with strong limb darkening.
Older posts