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Hoshi Stars星

The stars you can see without a telescope, with names, colours and distances; the 88 constellations with their lines and boundaries; the Messier objects; and seven map projections to draw them on.

Hoshi is the Japanese word 星 for a star. About the name

Contents

Reference · A star's profile: temperature, size, luminosity and disc size with their uncertainty, limb darkening, and the measured shapes of Altair, Regulus and Vega

StarShapetype

The shape of a star that was measured and is not a ball: Altair and Regulus are flattened by their spin, and Vega is seen from over its pole. Every number is a published measurement, named in source.

Import it

import type { StarShape } from "@johnmorrisdotca/hoshi-stars/profile";

Definition

interface StarShape {
    kind: "oblate" | "pole-on";
    equatorialRadius: number;
    polarRadius: number;
    polarTemperatureK: number;
    equatorialTemperatureK: number;
    inclinationDegrees: number;
    positionAngleDegrees: number;
    rotationPeriodDays: number | undefined;
    source: string;
}

Members

NameTypeDescription
kind"oblate" | "pole-on"

"oblate": flattened by its spin and seen well off the pole; "pole-on": spinning fast and seen almost along its axis, so it looks round.

equatorialRadiusnumber

The equatorial radius in solar radii.

polarRadiusnumber

The polar radius in solar radii.

polarTemperatureKnumber

The temperature at the poles in kelvin (the poles are hotter: gravity darkening).

equatorialTemperatureKnumber

The temperature at the equator in kelvin.

inclinationDegreesnumber

The angle between the spin axis and the line of sight, in degrees: 0 is pole-on, 90 edge-on.

positionAngleDegreesnumber

The direction of the spin axis on the sky, in degrees from north through east.

rotationPeriodDaysnumber | undefined

The spin period in days where the source gives one.

sourcestring

The published measurement the numbers are from.

Examples

import { starShape, type StarShape } from "@johnmorrisdotca/hoshi-stars/profile";

const altair: StarShape | undefined = starShape(7557);
console.log(altair?.equatorialRadius, altair?.polarRadius, altair?.source);
2.029 1.634 Monnier et al. 2007, Science 317, 342 (CHARA)

What it prints (run when this page was built)

View sourceEdit on GitHubMade from the source of @johnmorrisdotca/hoshi-stars 0.47.0.