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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

ProfileInputtype

What starProfile reads of a star: a Star has all of it, and so does anything built by hand (the Sun).

Import it

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

Definition

type ProfileInput = Pick<Star, "magnitude" | "colourIndex" | "spectralType" | "luminosityClass" | "parallaxMas" | "parallaxErrorMas" | "parallaxSource"> & {
    hr?: number | undefined;
};

Members

NameTypeDescription
magnitudenumber

Visual magnitude: smaller is brighter, and Sirius is -1.46.

parallaxMasnumber

The annual parallax in milliarcseconds, to a tenth where parallaxSource is "GCTP" (to a hundredth where it is "literature") and to a whole milliarcsecond otherwise; 0 where there is none (the distance is then unknown).

parallaxErrorMasnumber | undefined

The standard error of parallaxMas in milliarcseconds, or undefined where there is none: the Bright Star Catalogue states no error, so it is only given for a parallax from the Yale parallax catalogue or a published paper ("literature"). For the stars with a parallaxNote that says the error was widened, it is at least the parallax.

parallaxSource"GCTP" | "BSC" | "dynamical" | "literature" | undefined

Where the parallax is from: "GCTP" the Yale General Catalogue of Trigonometric Stellar Parallaxes (a measurement with an error), "BSC" the Bright Star Catalogue's trigonometric one, "dynamical" the Bright Star Catalogue's dynamical one (from the orbit of a binary), "literature" a distance typed from a published paper for a star whose catalogue parallax is poor (Betelgeuse, Rigel, Polaris; parallaxNote names it); undefined where there is none.

colourIndexnumber | undefined

The colour index B-V in magnitudes, or undefined where the catalogue has none. Hot blue stars are about -0.3, the Sun 0.65, cool red stars above 1.5.

spectralTypestring

The spectral type as the catalogue gives it, whole (M1-2Ia-Iab for Betelgeuse, A0Va for Vega, K1.5IIIFe-0.5); never empty for these 5,080.

luminosityClassLuminosityClass | undefined

The luminosity class in spectralType (Ia for Betelgeuse, V for Sirius and Vega): a supergiant, giant or dwarf. The first class where a range is given; undefined where the type states none (Am, K0).

hr (optional)number | undefined

Examples

import { starProfile, type ProfileInput } from "@johnmorrisdotca/hoshi-stars/profile";

const sun: ProfileInput = { magnitude: -26.74, colourIndex: 0.65, spectralType: "G2V", luminosityClass: "V", parallaxMas: 206_264_806.2, parallaxErrorMas: 1, parallaxSource: "GCTP" };
console.log(starProfile(sun).radius?.value.toFixed(2));
1.00

What it prints (run when this page was built)

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