# HD 137010

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High proper-motion star in the constellation Libra

HD 137010 2MASS image of HD 137010 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[4] 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[4] Mass 0.726±0.017 M☉ Radius 0.707±0.023 R☉ Luminosity 0.232+0.023 −0.021 L☉ Surface gravity (log g) 4.60±0.03 cgs Temperature 4,770±90 K Metallicity [Fe/H] -0.22 dex Age 4.8-10 Gyr Other designations BD−19 4097, HD 137010, HIP 75398, PPM 230195, EPIC 249661074, TIC 428919267[3] Database references SIMBAD data

**HD 137010** is a [K-type main-sequence star](/source/K-type_main-sequence_star) located approximately 146 light-years (44.86 parsecs) away in the [zodiac](/source/Zodiac) constellation of [Libra](/source/Libra_(constellation)).[3][4] It is a [solar analog](/source/Solar_analog), though cooler, dimmer, and smaller than the [Sun](/source/Sun), with an apparent visual magnitude of 10.14, making it invisible to the naked eye but readily observable with a telescope.[5] The star is notable for hosting the exoplanet candidate [HD 137010 b](/source/HD_137010_b),[6][7] a potential Earth-sized exoplanet detected via a single transit in archival data from [NASA](/source/NASA)'s [Kepler](/source/Kepler_space_telescope) K2 mission.[4]

## Characteristics

HD 137010 has a spectral type of K3.5 V,[8] indicating that it is a [main-sequence](/source/Main-sequence) star generating energy through the [thermonuclear fusion](/source/Thermonuclear_fusion) of hydrogen in its core. Its [effective temperature](/source/Effective_temperature) is 4,770 ± 90 K, giving the star an orange hue.[4][5] The star's mass is 0.726 ± 0.017 M☉, its radius is 0.707 ± 0.023 *R*☉, and its luminosity is 0.232+0.023 −0.021 L☉.[4] Its metallicity is slightly subsolar at [Fe/H] = −0.22 ± 0.07 dex.[5]

The star's age is estimated between 4.8 and 10 billion years (one analysis gives 7.4 ± 2.6 Gyr), consistent with its low magnetic activity.[4] Its surface gravity is log g = 4.60 ± 0.03 (cgs), and its density is 2.90+0.29 −0.26 g/cm³.[5]

## Planetary system

Inset focusing on the [transit](/source/Transit_(astronomy)) event

Artistic representation of exoplanet HD 137010 b

HD 137010 was observed by the Kepler space telescope for 88 days during K2 Campaign 15 (23 August to 19 November 2017).[4] Photometry revealed a single, shallow 10-hour transit event with a depth of 225 ± 10 parts per million (ppm) and a duration of 9.76+0.21 −0.18 hours.[5] The transit was identified through visual inspection of the light curve.[4] Analysis of the K2 photometry, high-resolution imaging (including new speckle observations), archival radial velocities, and Gaia/Hipparcos astrometry ruled out all conventional false-positive scenarios, such as background [eclipsing binaries](/source/Eclipsing_binaries), hierarchical triples, or instrumental artifacts. The event is best explained by a transiting planet candidate, designated HD 137010 b.[4][7]

The candidate has a radius of 1.06+0.06 −0.05 R🜨, consistent with a rocky [Super-Earth](/source/Super-Earth) or [Earth analog](/source/Earth_analog). Assuming negligible orbital eccentricity, the orbital period is estimated at 355+200 −59 days, with a semi-major axis of 0.88+0.32 −0.10 AU.[5] The planet receives an incident stellar flux of 0.29+0.11 −0.13 times that of Earth, placing it near the outer edge of the [habitable zone](/source/Habitable_zone).[4]

Size comparison of HD 137010 b with Earth and Mars

Its equilibrium temperature is approximately 205+17 −28 K (for a albedo of 0), potentially as low as 173 K for a higher albedo, this is colder than the average surface temperature of [Mars](/source/Mars).[4] Models suggest a 40% probability of lying in the conservative habitable zone and 51% in the optimistic habitable zone, a thick CO₂-rich atmosphere could potentially allow liquid water despite the low insolation.[4]

As of early 2026, HD 137010 b remains a planet candidate because only one transit has been observed, confirmation requires a second transit or supporting radial-velocity data.[4] The host star's brightness (V = 10.14) makes it an excellent target for future follow-up observations.[4]

The HD 137010 planetary system[6][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🜨

## References

1. ^ [***a***](#cite_ref-xhip_1-0) [***b***](#cite_ref-xhip_1-1) Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". *[Astronomy Letters](/source/Astronomy_Letters)*. **38** (5): 331. [arXiv](/source/ArXiv_(identifier)):[1108.4971](https://arxiv.org/abs/1108.4971). [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..331A](https://ui.adsabs.harvard.edu/abs/2012AstL...38..331A). [doi](/source/Doi_(identifier)):[10.1134/S1063773712050015](https://doi.org/10.1134%2FS1063773712050015). [XHIP record for this object](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-ref=VIZ681510a8389ecb&-out.src=V%2F137D%2FXHIP&-nav=cat%3AV%2F137D%26tab%3A{V%2F137D%2FXHIP}%26key%3Asource%3DV%2F137D%2FXHIP%26HTTPPRM%3A&-source=V%2F137D%2FXHIP&-out=HIP&HIP=75398&-out=Comp&-out=Gr&-out=RAJ2000&-out=DEJ2000&-out=Dist&-out=X&-out=Y&-out=Z&-out=SpType&-out=Simbad&-out=Hpmag&-out=Lum&-out=Cst) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-dr3_2-0) [***b***](#cite_ref-dr3_2-1) [***c***](#cite_ref-dr3_2-2) [***d***](#cite_ref-dr3_2-3) [***e***](#cite_ref-dr3_2-4) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D6254679341809369088%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-SIMBAD_3-0) [***b***](#cite_ref-SIMBAD_3-1) [***c***](#cite_ref-SIMBAD_3-2) [***d***](#cite_ref-SIMBAD_3-3) [***e***](#cite_ref-SIMBAD_3-4) ["HD 137010"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+137010). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2026-01-27.

1. ^ [***a***](#cite_ref-Alexander_Venner_et_al_(2026)_4-0) [***b***](#cite_ref-Alexander_Venner_et_al_(2026)_4-1) [***c***](#cite_ref-Alexander_Venner_et_al_(2026)_4-2) [***d***](#cite_ref-Alexander_Venner_et_al_(2026)_4-3) [***e***](#cite_ref-Alexander_Venner_et_al_(2026)_4-4) [***f***](#cite_ref-Alexander_Venner_et_al_(2026)_4-5) [***g***](#cite_ref-Alexander_Venner_et_al_(2026)_4-6) [***h***](#cite_ref-Alexander_Venner_et_al_(2026)_4-7) [***i***](#cite_ref-Alexander_Venner_et_al_(2026)_4-8) [***j***](#cite_ref-Alexander_Venner_et_al_(2026)_4-9) [***k***](#cite_ref-Alexander_Venner_et_al_(2026)_4-10) [***l***](#cite_ref-Alexander_Venner_et_al_(2026)_4-11) [***m***](#cite_ref-Alexander_Venner_et_al_(2026)_4-12) [***n***](#cite_ref-Alexander_Venner_et_al_(2026)_4-13) [***o***](#cite_ref-Alexander_Venner_et_al_(2026)_4-14) [***p***](#cite_ref-Alexander_Venner_et_al_(2026)_4-15) Venner, Alexander; Vanderburg, Andrew; X. Huang, Chelsea; Dholakia, Shishir; Schwengeler, Hans Martin; Howell, Steve B.; Wittenmyer, Robert A.; Kristiansen, Martti H.; Omohundro, Mark; Terentev, Ivan A. (2026). ["A Cool Earth-sized Planet Candidate Transiting a Tenth Magnitude K-dwarf From K2"](https://doi.org/10.3847%2F2041-8213%2Fadf06f). *The Astrophysical Journal*. **997** (2): L38. [arXiv](/source/ArXiv_(identifier)):[2601.19870](https://arxiv.org/abs/2601.19870). [Bibcode](/source/Bibcode_(identifier)):[2026ApJ...997L..38V](https://ui.adsabs.harvard.edu/abs/2026ApJ...997L..38V). [doi](/source/Doi_(identifier)):[10.3847/2041-8213/adf06f](https://doi.org/10.3847%2F2041-8213%2Fadf06f).

1. ^ [***a***](#cite_ref-:EPA_5-0) [***b***](#cite_ref-:EPA_5-1) [***c***](#cite_ref-:EPA_5-2) [***d***](#cite_ref-:EPA_5-3) [***e***](#cite_ref-:EPA_5-4) [***f***](#cite_ref-:EPA_5-5) ["HD 137010 | NASA Exoplanet Archive"](https://exoplanetarchive.ipac.caltech.edu/overview/HD%20137010). *exoplanetarchive.ipac.caltech.edu*. Retrieved 2026-03-29.

1. ^ [***a***](#cite_ref-Martin-2026_6-0) [***b***](#cite_ref-Martin-2026_6-1) Martin, Pierre-Yves (2026). ["Planet HD 137010 b"](https://exoplanet.eu/catalog/hd_137010_b--11844/). *exoplanet.eu*. Retrieved 2026-01-28.

1. ^ [***a***](#cite_ref-Discovery-Alert-2026_7-0) [***b***](#cite_ref-Discovery-Alert-2026_7-1) ["Discovery Alert: An Ice-Cold Earth? - NASA Science"](https://science.nasa.gov/universe/exoplanets/discovery-alert-an-ice-cold-earth/). 2026-01-27. Retrieved 2026-01-27.

1. **[^](#cite_ref-8)** Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (July 2006). ["Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample"](https://iopscience.iop.org/article/10.1086/504637). *The Astronomical Journal*. **132** (1): 161–170. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0603770](https://arxiv.org/abs/astro-ph/0603770). [doi](/source/Doi_(identifier)):[10.1086/504637](https://doi.org/10.1086%2F504637). [ISSN](/source/ISSN_(identifier)) [0004-6256](https://search.worldcat.org/issn/0004-6256).

v t e Constellation of Libra List of stars in Libra Libra in Chinese astronomy Stars Bayer α1 α2 (Zubenelgenubi) β (Zubeneschamali) γ (Zubenelhakrabi) δ ε ζ1 ζ2 ζ3 ζ4 η θ ι1 ι2 κ λ μ ν ξ1 ξ2 ο σ (Brachium) τ υ Flamsteed 2 3 4 5 10 11 12 16 17 18 22 23 26 28 30 36 37 41 42 47 48 49 50 Variable HN HO KU KX HR 5504 5455 HD 133131 134439 134440 135485 137010 139139 140283 141569 141937 Other 2M1510 2MASS 1507−1627 CWISEP J1446−2317 HE 1523−0901 WASP-57 WISE 1534−1043 WISE 1541−2250 Exoplanets 23 Librae b c Gliese 581b c e HD 137010 b (unconfirmed) K2-315b WASP-189b Star clusters NGC 5897 Galaxies NGC 5597 5605 5716 5728 5792 5793 5861 5885 5890 5898 5915 5917 Other AP Librae IC 1059 IRAS 14348−1447 PKS 1510−089 PKS 1519−273 QSO B1524−136 RXC J1504.1−0248 BCG Category

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Adapted from the Wikipedia article [HD 137010](https://en.wikipedia.org/wiki/HD_137010) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/HD_137010?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.