Reference · The 73 star systems within 20 light-years, with names in English and Japanese, place, distance, companions and the source of each value

`NearStar`type

One star system within 20 light-years: a single star or a group, at a place on the sky, with its distance and where each value comes from. Positions are J2000.

Import it

import type { NearStar } from "@johnmorrisdotca/hoshi-stars/near-stars";

Definition

interface NearStar {
    id: string;
    name: string;
    nameJa: string | undefined;
    designation: string;
    aliases: readonly string[];
    constellation: string;
    starsAtLeast: number;
    rightAscension: number;
    declination: number;
    positionErrorArcsec: number | undefined;
    parallaxMas: number;
    parallaxErrorMas: number | undefined;
    lightYears: number;
    lightYearsError: number | undefined;
    spectralType: string | undefined;
    luminosityClass: LuminosityClass | undefined;
    magnitude: number | undefined;
    properMotionRaMas: number;
    properMotionDecMas: number;
    members: readonly NearStarMember[];
    flags: NearStarFlags;
    sources: NearStarSources;
}

Members

Name	Type	Description
`id`	`string`	A key that stays the same: `alpha-centauri`, `barnards-star`.
`name`	`string`	The system's name (`Alpha Centauri`, `Barnard's Star`, `Wolf 359`).
`nameJa`	`string \| undefined`	The name in Japanese where known, else `undefined`.
`designation`	`string`	The Bayer letter and constellation, the catalogue's name or its number (`α Cen`, `L 726-8A`).
`aliases`	`readonly string[]`	Other names the sources give it, for `nearStarByName`.
`constellation`	`string`	The IAU three-letter constellation abbreviation the system lies in (`Cen`).
`starsAtLeast`	`number`	The number of stars in the system as published for the well-known multiples, at least: 3 for Alpha Centauri, 1 for a star with no known companion.
`rightAscension`	`number`	Right ascension of the primary star in degrees at J2000, 0 up to 360.
`declination`	`number`	Declination of the primary star in degrees at J2000, -90 to 90.
`positionErrorArcsec`	`number \| undefined`	The error of the position in arc-seconds where the table gives one (2MASS and Yale positions), else `undefined`.
`parallaxMas`	`number`	The annual parallax of the primary in milliarcseconds.
`parallaxErrorMas`	`number \| undefined`	The standard error of `parallaxMas`, or `undefined`.
`lightYears`	`number`	The distance in light-years: 3,261.56 divided by the parallax in milliarcseconds.
`lightYearsError`	`number \| undefined`	The error of `lightYears`, or `undefined`: the distance times the parallax's relative error.
`spectralType`	`string \| undefined`	The spectral type of the primary, or `undefined` where the source gives none (LPP 731-58).
`luminosityClass`	`LuminosityClass \| undefined`	The luminosity class in `spectralType`, or `undefined`.
`magnitude`	`number \| undefined`	The V magnitude of the primary, or `undefined`.
`properMotionRaMas`	`number`	Proper motion in right ascension in milliarcseconds a year, already multiplied by cos(declination); 0 where there is none (`sources.properMotion` is then `undefined`).
`properMotionDecMas`	`number`	Proper motion in declination in milliarcseconds a year; 0 where there is none.
`members`	`readonly NearStarMember[]`	The stars of the system, the primary first, then the companions the sources give; a companion typed in has no position of its own.
`flags`	`NearStarFlags`	What to be careful about.
`sources`	`NearStarSources`	Where each value comes from.

Examples

import { nearStarByName, type NearStar } from "@johnmorrisdotca/hoshi-stars/near-stars";

const proxima: NearStar = nearStarByName("Proxima Centauri")!;
console.log(proxima.name, proxima.nameJa, proxima.lightYears.toFixed(2), proxima.sources.distance);

Alpha Centauri ケンタウルス座α星 4.35 GCTP

What it prints (run when this page was built)

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

NearStartype

Definition

Members

Examples

`NearStar`type