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SAX J1819.3-2525 | Black Holes | Apex Andromeda | Apex Andromeda

Black Holes/SAX J1819.3-2525

ConfirmedStellar-Mass Binary

Unified black-hole record

SAX J1819.3-2525

Dynamically confirmed black hole

Also known as V4641 Sgr · XTE J1819-254

Mass6.4 M☉

Distance20.222K ly

HostNot reported by source catalogs

Drag to orbitScroll to zoomEmbedded animation playing

3D model “Blackhole” by rubykamen, licensed under CC BY 4.0.

Catalog record

Identity and classification

ID: vizier-blackcat:J/ApJS/222/15/table12:59
Canonical name: SAX J1819.3-2525
Alternate names: V4641 Sgr · XTE J1819-254
Black-hole type: Stellar-Mass Binary
Status: Confirmed
Population: Catalog
Confidence: Dynamically confirmed black hole
Host galaxy: Not reported by source catalogs

Position

Coordinates and distance

Right ascension (RA): 274.83991667°
Declination (Dec): -25.40697222°
Galactic longitude (l): 6.774°
Galactic latitude (b): -4.7891°
Distance: 20.222K light-years
Distance error: 2.283K light-years
Redshift: Not reported by source catalogs

Physical profile

Mass, spin, and system

Mass: 6.4 solar masses
Mass error, lower: 0.6 solar masses
Mass error, upper: 0.6 solar masses
Spin: Not reported by source catalogs
Companion: V4641 Sgr
Companion type: B9III
Orbital period: 2.8173 days
Inclination: 72°

Evidence

Detection and discovery

Detection method: Dynamical mass measurement in an X-ray binary
Discovery year: 1999
Discovery observatory: Be,Rx
X-ray properties: WATCHDOG source type: BH,T,R,J
Radio properties: Not reported by source catalogs
Gravitational-wave event: Not reported by source catalogs

Provenance

Sources and refresh state

Source catalog: VizieR J/ApJS/222/15 (WATCHDOG/BlackCAT)
Source reference: 2016ApJS..222...15T
Last updated: 2026-08-31T01:34:41.049Z
Source record: Open provider record ↗