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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 · Black holes: 301 with a place, a mass and distance with ranges, how each was found and the paper behind each fact

BlackHoletype

One black hole. Positions are J2000 (equator and equinox of 2000), the same frame as Star and DeepSkyObject.

Import it

import type { BlackHole } from "@johnmorrisdotca/hoshi-stars/black-holes";

Definition

interface BlackHole {
    id: string;
    name: string;
    otherNames: string[];
    kind: BlackHoleKind;
    status: "confirmed" | "candidate";
    constellation: string;
    rightAscension: number;
    declination: number;
    massSuns: BlackHoleMeasure | undefined;
    distanceParsecs: BlackHoleMeasure | undefined;
    companion: string | undefined;
    companionType: string | undefined;
    foundBy: BlackHoleFound;
    year: number | undefined;
    sources: BlackHoleSources;
    note: string | undefined;
}

Members

NameTypeDescription
idstring

A short unique id made of lower-case letters, digits and hyphens (cygnus-x-1, m87).

namestring

The name: the object's usual name (Cygnus X-1), or for a supermassive black hole its galaxy's name with a star after it (M87*, NGC 4258*), as astronomers write Sagittarius A*.

otherNamesstring[]

Other names that blackHole finds too (Cyg X-1, HDE 226868; for M87*, M87 and NGC 4486). Usually a few, sometimes none.

kind"stellar" | "quiet" | "supermassive"

The kind: stellar, quiet or supermassive.

status"confirmed" | "candidate"

confirmed where the mass of the invisible object is measured above what a neutron star can have, from its pull on a companion, on stars, gas or masers around it, or from an image; else candidate: a source that acts like a black hole.

constellationstring

The IAU three-letter constellation abbreviation (Cyg), the same text as Star.constellation.

rightAscensionnumber

Right ascension in degrees at J2000, 0 up to 360. Given to 0.0001 degree (0.36 arc-second).

declinationnumber

Declination in degrees at J2000, -90 to 90. Given to 0.0001 degree.

massSunsBlackHoleMeasure | undefined

The mass in Suns (solar masses) with its range, or undefined where there is no measure.

distanceParsecsBlackHoleMeasure | undefined

The distance in parsecs (1 parsec is 3.2616 light-years) with its range, or undefined.

companionstring | undefined

The companion star's designation (HDE 226868, V404 Cyg), or undefined where it has none or the black hole has no companion.

companionTypestring | undefined

The companion star's spectral type or kind (O supergiant, K3 III, red giant), or undefined.

foundBy"image" | "x-rays" | "orbit" | "microlensing" | "stars" | "gas" | "masers" | "echoes"

How it was found.

yearnumber | undefined

The year: for a stellar black hole when its X-ray source was discovered, for a quiet one the year of its discovery paper, for a supermassive one the year of the mass measurement used. undefined where unknown.

sourcesBlackHoleSources

The papers behind each fact.

notestring | undefined

A short English note where the facts need one (a disputed mass, an unusual place), else undefined.

Examples

import { blackHole, type BlackHole } from "@johnmorrisdotca/hoshi-stars/black-holes";

const cygnus: BlackHole = blackHole("Cygnus X-1")!;
console.log(cygnus.id, cygnus.kind, cygnus.massSuns?.value, cygnus.companion, cygnus.year);
cygnus-x-1 stellar 21.2 HDE 226868 1964

What it prints (run when this page was built)

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