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H 1705-250 | Black Holes | Apex Andromeda | Apex Andromeda

Black Holes/H 1705-250

ConfirmedStellar-Mass Binary

Unified black-hole record

H 1705-250

Dynamically confirmed black hole

Also known as V2107 Oph · Nova Oph 1977

Mass4.9 M☉

Distance28.049K 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/table12:25
Canonical name: H 1705-250
Alternate names: V2107 Oph · Nova Oph 1977
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): 257.06466667°
Declination (Dec): -25.09170833°
Galactic longitude (l): 358.5874°
Galactic latitude (b): 9.0569°
Distance: 28.049K light-years
Distance error: 6.849K light-years
Redshift: Not reported by source catalogs

Physical profile

Mass, spin, and system

Mass: 4.9 solar masses
Mass error, lower: Not reported by source catalogs
Mass error, upper: Not reported by source catalogs
Spin: Not reported by source catalogs
Companion: N. Oph 77
Companion type: K3-M0V
Orbital period: 0.52125 days
Inclination: 48°

Evidence

Detection and discovery

Detection method: Dynamical mass measurement in an X-ray binary
Discovery year: 1977
Discovery observatory: Ar,H
X-ray properties: WATCHDOG source type: BH,T
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 ↗