 This artist's impression shows a dramatic close-up of the extrasolar planet XO-1b passing in front of a Sun-like star 600 light-years from Earth. The Jupiter-sized planet is in a tight four-day orbit around the star. Credit:NASA, ESA and G. Bacon (STScI) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Corona Borealis[1] |
| Right ascension | 16h 02m 11.8462s[2] |
| Declination | +28° 10′ 10.420″[2] |
| Apparent magnitude (V) | 11.19 ± 0.03[3] |
| Characteristics | |
| Spectral type | G1V[3] |
| Apparent magnitude (B) | 11.85 ± 0.04[3] |
| Apparent magnitude (V) | 11.19 ± 0.03[3] |
| Apparent magnitude (J) | 9.939 ± 0.022[4] |
| Apparent magnitude (H) | 9.601 ± 0.017[4] |
| Apparent magnitude (K) | 9.527 ± 0.015[4] |
| Variable type | Planetary transit variable[3] |
| Astrometry | |
| Radial velocity (Rv) | 2.49±0.32[2] km/s |
| Proper motion (μ) | RA: −17.349(12)mas/yr[2] Dec.: 14.780(15)mas/yr[2] |
| Parallax (π) | 6.1489±0.0136 mas[2] |
| Distance | 530 ± 1 ly (162.6 ± 0.4 pc) |
| Absolute magnitude (MV) | 5.02+0.14 −0.16[5] |
| Details | |
| Mass | 1.027+0.057 −0.061[5] M☉ |
| Radius | 0.94 ± 0.02[6] R☉ |
| Luminosity | 0.86+0.12 −0.10[5] L☉ |
| Surface gravity (log g) | 4.50 ± 0.01[7] cgs |
| Temperature | 5738 ± 65[7] K |
| Metallicity[Fe/H] | −0.06 ± 0.07[7] dex |
| Rotational velocity (v sin i) | 1.1 ± 1.0[7] km/s |
| Age | 1.0+3.1 −0.9[5] Gyr |
| Other designations | |
| Moldoveanu,BD+28 2507,TOI-2021,TIC 236312126,TYC 2041-1657-1,GSC 02041-01657,2MASS J16021184+2810105[8] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
XO-1 is amagnitude 11G-type main-sequence star located approximately 530light-years away[2] in theconstellationCorona Borealis. XO-1 has amass andradius similar to theSun.In 2006 theextrasolar planetXO-1b was discovered orbiting XO-1 by thetransit method using theXO Telescope.[3]
The star XO-1 is namedMoldoveanu. The name was selected in theNameExoWorlds campaign byRomania, during the 100th anniversary of theIAU.Moldoveanu is the highest peak in Romania.[9][10][11]
TheXO Project is an international team of professional and amateurastronomers which discovered theJupiter-sized planet orbiting around XO-1. The team, led byPeter R. McCullough of the Space Telescope Science Institute in Baltimore, includes four amateur astronomers from North America and Europe. The planet was confirmed using theHarlan J. Smith Telescope andHobby-Eberly Telescope atMcDonald Observatory of theUniversity of Texas.[3] An independent confirmation of the planet was made by theWide Angle Search for Planets project.[12] In 2019, the planet was namedNegoiu, afterNegoiu Peak inRomania.
Further observations with theNICMOS instrument on board theHubble Space Telescope detected the presence of water vapor,methane, andcarbon dioxide in the atmosphere of XO-1b.[13] However an independent reinvestigation of the same data was unable to reproduce these results.[14]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Negoiu | 0.907±0.022 MJ | 0.04914±0.00045 | 3.94150514(20) | <0.019 | 88.84±0.22° | 1.199±0.017 RJ |
