Astronomy:HAT-P-26

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Short description: Star in the constellation Virgo
HAT-P-26 / Guahayona
Observation data
Equinox J2000.0]] (ICRS)
Constellation Virgo
Right ascension  14h 12m 37.53311s[1]
Declination +04° 03′ 36.1166″[1]
Apparent magnitude (V) 11.76[2]
Characteristics
Spectral type K1V
Astrometry
Radial velocity (Rv)14.10±0.39[1] km/s
Proper motion (μ) RA: 37.735[1] mas/yr
Dec.: -142.816[1] mas/yr
Parallax (π)6.9985 ± 0.0204[1] mas
Distance466 ± 1 ly
(142.9 ± 0.4 pc)
Details[3]
Mass0.81 M
Radius0.78 R
Temperature5079±88 K
Metallicity-0.04±0.08[4]
Rotational velocity (v sin i)1.8 km/s
Other designations
Guahayona, Gaia DR2 3668036348641580288, TYC 320-1027-1, GSC 0320-01027, 2MASS J14123753+0403359[2]
Database references
SIMBADdata

HAT-P-26 is a K-type main-sequence star about 466 light-years (143 parsecs) away. A survey in 2015 did not find any stellar companions in orbit around it,[5] although a red dwarf companion with a temperature 4000+100−350 K is suspected on wide orbit.[6]

Nomenclature

The designation HAT-P-26 indicates that this was the 26th star found to have a planet by the HATNet Project.

In August 2022, this planetary system was included among 20 systems to be named by the third NameExoWorlds project.[7] The approved names, proposed by a team from Puerto Rico, were announced in June 2023. HAT-P-26 is named Guahayona and its planet is named Guataubá, after figures from Taíno mythology.[8]

Planetary system

In 2010 a transiting hot Neptune like planet was detected.[4] The transiting planet HAT-P-26b was detected by the HATNet Project using telescopes located in Hawaii and Arizona. The planet is likely formed by pebble accretion mechanism.[9] The transmission spectrum of HAT-P-26b was taken in 2015, with the best fit favouring either a cloudless atmosphere or an atmosphere with a low-lying cloud deck.[10] The atmospheric composition of the planet was measured in 2019, and a water vapor volume fraction of 1.5+2.1−0.9% was detected. HAT-P-26 is carbon depleted, with a C/O ratio constrained to less than 0.33. Also, the planet's atmosphere contains light metal hydrides.[11] The measured planetary temperature is equal to 563+58−54 K.

In 2019, a transit timing variation analysis of HAT-P-26b indicated the possible presence of a second planet in the system on a wide, 1141-days orbit.[12]

In 2023, the atmosphere of the planet was confirmed to contain 12±2% steam at 590+20−30K.[13]

The HAT-P-26 planetary system[14][12]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b / Guataubá >0.0585±0.00717 MJ 0.0479±0.0006 4.234516±0.000015 0.124±0.060 88.6±0.9° 0.5647±0.0517 RJ
c (unconfirmed) 1141

References

  1. 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. 2.0 2.1 HAT-P-26 -- High proper-motion Star
  3. D. Ehrenreich and J.-M. Désert, "Mass-loss rates for transiting exoplanets", A&A 529, A136 (2011)
  4. 4.0 4.1 Hartman, J. D.; Bakos, G. Á.; Kipping, D. M.; Torres, G.; Kovács, G.; Noyes, R. W.; Latham, D. W.; Howard, A. W. et al. (2010), "HAT-P-26b: A LOW-DENSITY NEPTUNE-MASS PLANET TRANSITING A K STAR", The Astrophysical Journal 728 (2): 138, doi:10.1088/0004-637X/728/2/138 
  5. Wöllert, Maria; Brandner, Wolfgang; Bergfors, Carolina; Henning, Thomas (2015), "A Lucky Imaging search for stellar companions to transiting planet host stars", Astronomy & Astrophysics 575: A23, doi:10.1051/0004-6361/201424091, Bibcode2015A&A...575A..23W 
  6. Piskorz, Danielle; Knutson, Heather A.; Ngo, Henry; Muirhead, Philip S.; Batygin, Konstantin; Crepp, Justin R.; Hinkley, Sasha; Morton, Timothy D. (2015), "Friends of Hot Jupiters. III. An Infrared Spectroscopic Search for Low-Mass Stellar Companions", The Astrophysical Journal 814 (2): 148, doi:10.1088/0004-637X/814/2/148, Bibcode2015ApJ...814..148P 
  7. "List of ExoWorlds 2022". IAU. 8 August 2022. https://www.nameexoworlds.iau.org/2022exoworlds. 
  8. "2022 Approved Names". IAU. https://www.nameexoworlds.iau.org/2022approved-names. 
  9. Mohamad Ali-Dib, Gunjan Lakhlani, "Possible formation pathways for the low-density Neptune-mass planet HAT-P-26b"
  10. Stevenson, Kevin B.; Bean, Jacob L.; Seifahrt, Andreas; Gilbert, Gregory J.; Line, Michael R.; Désert, Jean-Michel; Fortney, Jonathan J. (2015), "A SEARCH FOR WATER IN THE ATMOSPHERE OF HAT-P-26b USING LDSS-3C", The Astrophysical Journal 817 (2): 141, doi:10.3847/0004-637X/817/2/141 
  11. MacDonald, Ryan J.; Madhusudhan, Nikku (2019), "The Metal-Rich Atmosphere of the Neptune HAT-P-26b", Monthly Notices of the Royal Astronomical Society 486: 1292–1315, doi:10.1093/mnras/stz789 
  12. 12.0 12.1 von Essen, C.; Wedemeyer, S.; Sosa, M. S.; Hjorth, M.; Parkash, V.; Freudenthal, J.; Mallonn, M.; Miculán, R. G. et al. (2019), "Indications for transit timing variations in the exo-Neptune HAT-P-26b", Astronomy & Astrophysics 628: A116, doi:10.1051/0004-6361/201731966, Bibcode2019A&A...628A.116V 
  13. A-thano, Napaporn; Awiphan, Supachai; Jiang, Ing-Guey; Kerins, Eamonn; Priyadarshi, Akshay; McDonald, Iain; Joshi, Yogesh C.; Chulikorn, Thansuda et al. (2023), "Revisiting the Transit Timing and Atmosphere Characterization of the Neptune-mass Planet HAT-P-26 b", The Astronomical Journal 166 (6): 223, doi:10.3847/1538-3881/acfeea, Bibcode2023AJ....166..223A 
  14. Planet HAT-P-26 b on exoplanet.eu

Coordinates: Sky map 14h 12m 37.5330s, +04° 03′ 36.1177″