Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Leo |
Right ascension | 11h 33m 12.125s [1] |
Declination | +01° 08′ 24.87″ [1] |
Apparent magnitude (V) | 17.80 [2] |
Characteristics | |
Spectral type | sdB [3] |
Astrometry | |
Radial velocity (Rv) | 518 [4] km/s |
Proper motion (μ) |
RA: -1
[5]
mas/
yr Dec.: 1 [5] mas/ yr |
Distance | 180,000
ly (55,000 [6] pc) |
Details [7] | |
Mass | 3.7 M☉ |
Radius | 4.0 R☉ |
Luminosity | 300 L☉ |
Surface gravity (log g) | 3.8 cgs |
Temperature | 12,000 K |
Rotational velocity (v sin i) | 55 km/s |
Age | 150 Myr |
Other designations | |
Database references | |
SIMBAD | data |
HVS 7 -- hyper-velocity star 7, otherwise known as SDSS J113312.12+010824.9 is a rare star that has been accelerated to faster than our Milky Way Galaxy's escape velocity. [7] [8] In 2013 a team under N. Przybilla wrote that the star had a chemically peculiar photosphere, which masked its origins. [7] The star was first cataloged during the Sloan Digital Sky Survey. It was identified as a hyper-velocity star in 2006. [8]
The star has a chemically peculiar spectrum, roughly matching a B-type subdwarf. Stars in this region of the Hertzsprung–Russell diagram are expected to either be hot horizontal branch stars, low-mass helium-burning objects, or moderate mass hydrogen-burning stars slightly below the main sequence. The high rotational velocity of HVS 7 means it is likely to be a young star near the main sequence, around 150 million years old and 3.7 times the mass of the sun. [7]
Such a surface abundance pattern is caused by atomic diffusion in a possibly magnetically stabilised, non-convective atmosphere. Hence all chemical information on the star's place of birth and its evolution has been washed out. High precision astrometry is the only means to validate a GC origin for HVS 7.
Here we report the two most recently discovered HVSs: SDSS J110557.45+093439.5 and possibly SDSS J113312.12+010824, traveling with Galactic rest-frame velocities at least +508+/-12 and +418+/-10 km s-1, respectively.
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Leo |
Right ascension | 11h 33m 12.125s [1] |
Declination | +01° 08′ 24.87″ [1] |
Apparent magnitude (V) | 17.80 [2] |
Characteristics | |
Spectral type | sdB [3] |
Astrometry | |
Radial velocity (Rv) | 518 [4] km/s |
Proper motion (μ) |
RA: -1
[5]
mas/
yr Dec.: 1 [5] mas/ yr |
Distance | 180,000
ly (55,000 [6] pc) |
Details [7] | |
Mass | 3.7 M☉ |
Radius | 4.0 R☉ |
Luminosity | 300 L☉ |
Surface gravity (log g) | 3.8 cgs |
Temperature | 12,000 K |
Rotational velocity (v sin i) | 55 km/s |
Age | 150 Myr |
Other designations | |
Database references | |
SIMBAD | data |
HVS 7 -- hyper-velocity star 7, otherwise known as SDSS J113312.12+010824.9 is a rare star that has been accelerated to faster than our Milky Way Galaxy's escape velocity. [7] [8] In 2013 a team under N. Przybilla wrote that the star had a chemically peculiar photosphere, which masked its origins. [7] The star was first cataloged during the Sloan Digital Sky Survey. It was identified as a hyper-velocity star in 2006. [8]
The star has a chemically peculiar spectrum, roughly matching a B-type subdwarf. Stars in this region of the Hertzsprung–Russell diagram are expected to either be hot horizontal branch stars, low-mass helium-burning objects, or moderate mass hydrogen-burning stars slightly below the main sequence. The high rotational velocity of HVS 7 means it is likely to be a young star near the main sequence, around 150 million years old and 3.7 times the mass of the sun. [7]
Such a surface abundance pattern is caused by atomic diffusion in a possibly magnetically stabilised, non-convective atmosphere. Hence all chemical information on the star's place of birth and its evolution has been washed out. High precision astrometry is the only means to validate a GC origin for HVS 7.
Here we report the two most recently discovered HVSs: SDSS J110557.45+093439.5 and possibly SDSS J113312.12+010824, traveling with Galactic rest-frame velocities at least +508+/-12 and +418+/-10 km s-1, respectively.