HD 137010
High proper-motion star in the constellation Libra
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HD 137010 (also known as EPIC 249661074) is a solar analog star located approximately 146 light-years away in the zodiac constellation of Libra. Its apparent visual magnitude is 10.14, making it invisible to the naked eye but observable with a standard telescope[3]. It likely has an orbiting exoplanet, known as HD 137010 b, which may be a very Earth-like exoplanet in terms of orbital characteristics but cooler than Earth.[6][4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Libra[1] |
| Right ascension | 15h 24m 21.25106s[2] |
| Declination | −19° 44′ 21.6785″[2] |
| Apparent magnitude (V) | 10.14[3] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | K3.5 V[3] |
| Astrometry | |
| Radial velocity (Rv) | +27.866[3] km/s |
| Proper motion (μ) | RA: +228.536[2] mas/yr Dec.: −248.158[2] mas/yr |
| Parallax (π) | 22.2922±0.0174 mas[2] |
| Distance | 146.3 ± 0.1 ly (44.86 ± 0.04 pc) |
| Absolute magnitude (MV) | +7.2[1] |
| Details | |
| Mass | 0.726±0.017[4] M☉ |
| Radius | 0.707±0.023[4] R☉ |
| Luminosity | 0.232+0.023 −0.021[4] L☉ |
| Surface gravity (log g) | 4.60±0.03[4] cgs |
| Temperature | 4,770±90[4] K |
| Metallicity [Fe/H] | -0.22[4] dex |
| Age | 4.8-10[4] Gyr |
| Other designations | |
| BD−19 4097, HD 137010, HIP 75398, PPM 230195, EPIC 249661074[5][4], TIC 428919267 | |
| Database references | |
| SIMBAD | data |
Stellar characteristics
HD 137010 has a spectral type of K3.5 V,[7] indicating that it is a main-sequence star generating energy through the thermonuclear fusion of hydrogen in its core. This energy is radiated from its outer envelope at an effective temperature of around 4770 K, giving it an orange hue. Its age is estimated to be between 4.80 and 10.0 billion years. HD 137010 is slightly smaller than the Sun, with a mass of approximately 72.6% of the Sun's mass and a radius of 70.7% of the Sun's radius.[5][4]
Planetary system
HD 137010 was observed by the Kepler space telescope for 88 days in 2017 during the K2 mission. Its photometry shows the presence of a single transit during this period. It is possible to rule out that this detection is a false positive and it is therefore not an instrumental error, nor contamination of the light curve due to the presence, for example, of a nearby eclipsing binary.[4] This transit was therefore very likely produced by a genuine exoplanet, then designated HD 137010 b, even though it remains only a candidate in the absence of further transits or independent confirmation by another detection method.[6]
In early 2026, an analysis of archival data obtained during the 15th campaign of the K2 mission of the Kepler Space Telescope in 2017 revealed a single 10-hour transit event that occurred on the K-type dwarf star HD 137010 with an apparent magnitude of 10.1.[4] The transit was relatively shallow (225±10 ppm), but detectable with a high signal-to-noise ratio due to the exceptionally high photometric precision achieved for the target object. Analysis of K2 photometry, historical and new observations, as well as archival radial velocities and astrometry, strongly indicates that the event was astrophysical in nature, occurred directly on the target object, and is best explained by the transit of a candidate planet.[6][4]
The single observed transit implies a radius of 1.06 R🜨, a negligibly small orbital eccentricity, and an orbital period of 355 days (0.88 AU). The predicted incident flux is 0.29+0.11
−0.13 I⊕.[5][4] This means that HD 137010 b is located at the outer edge of the habitable zone.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | — | 0.88+0.3 −0.1 |
355.0+200.0 −59.0 |
0 | >89.82+0.05 −0.03° |
1.06+0.06 −0.05 R🜨 |