HVS 7
Hyper-velocity star in the constellation Leo
From Wikipedia, the free encyclopedia
HVS 7 or 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]
| 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 | |
| SDSS J113312.12+010824.9, EPIC 201540171 | |
| Database references | |
| SIMBAD | data |
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]