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Globular Cluster M31 G1
About the Object
- R.A. PositionR.A. PositionRight ascension – analogous to longitude – is one component of an object's position.00h 32m 46.9m
- Dec. PositionDec. PositionDeclination – analogous to latitude – is one component of an object's position.+39° 34' 42"
- ConstellationConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.Andromeda
- DistanceDistanceThe physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.G1's distance to Earth is about 2.2 million light-years (675,000 parsecs). Its distance to the galactic center of M31 is about 120,000 light-years (36.8 kiloparsecs).
- DimensionsDimensionsThe physical size of the object or the apparent angle it subtends on the sky.The image is about 24 arcseconds (770 parsecs or 2500 light-years) in the horizontal dimension. Mass of the black hole: 20,000 times the mass of the Sun
About the Data
- Data DescriptionData DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.WFPC2 Data Principal Astronomers: M. Rich (UCLA), K. Mighell (NOAO), and J. Neill (Columbia U.), and W. Freedman (Carnegie Observatories) STIS Data Principal Astronomers: M. Rich (UCLA), K. Gebhardt (U. Texas at Austin), and L. Ho (Carnegie Inst. of Washington) - InstrumentInstrumentThe science instrument used to produce the data.HST>WFPC2 and HST>STIS
- Exposure DatesExposure DatesThe date(s) that the telescope made its observations and the total exposure time.July 1994, Exposure Time: 1.9 hours (WFPC2), and October - November 2001, Exposure Time: 8.3 hours (STIS)
- FiltersFiltersThe camera filters that were used in the science observations.WFPC2: F555W (V) and F814W (I) STIS: G430L, G750M
- Object NameObject NameA name or catalog number that astronomers use to identify an astronomical object.G1 in M31, Mayall II
- Object DescriptionObject DescriptionThe type of astronomical object.Globular Cluster in the Milky Way Galaxy
- Release DateSeptember 17, 2002
- Science ReleaseHubble Discovers Black Holes in Unexpected Places
- CreditsNASA and Michael Rich (UCLA)
Compass and Scale
Compass and ScaleAn astronomical image with a scale that shows how large an object is on the sky, a compass that shows how the object is oriented on the sky, and the filters with which the image was made.
Related Images & Videos
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Last Updated
Mar 14, 2025
Contact
Media
Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
