HIP 57050

HIP 57050 (GJ 1148 / LHS 2443 / G 122-40 / Ross 1003) is a red dwarf 36 light-years from the Sun with a planetary companion HIP 57050 b.[2][7]

HIP 57050
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension  11h 41m 44.6360s[1]
Declination +42° 45′ 07.1048″[1]
Apparent magnitude (V) 13.795[2]
Characteristics
Spectral type M4.0Ve[3]
U−B color index +1.52[4]
B−V color index +1.13[4]
V−R color index +1.19[4]
Astrometry
Radial velocity (Rv)−9.10[5] km/s
Proper motion (μ) RA: −575.654±0.066[1] mas/yr
Dec.: −89.974±0.070[1] mas/yr
Parallax (π)90.7623 ± 0.0527[1] mas
Distance35.94 ± 0.02 ly
(11.018 ± 0.006 pc)
Absolute magnitude (MV)11.61[4]
Details[6]
Mass0.34 ± 0.03 M☉
Radius0.4 R☉
Luminosity0.01486 L☉
Surface gravity (log g)4.67 cgs
Temperature3190 K
Rotation98
Other designations
GJ 1148, LTT 13210, Ross 1003, 2MASS J11414471+4245072[2]
Database references
SIMBADdata
ARICNSdata

HIP 57050 has a metallicity twice that of the Sun and is among the highest in the immediate solar neighborhood.[6]

Planetary system

A team led by astronomer Nader Haghighipour reported the discovery of a Saturn-sized planet in the habitable zone of the star in 2010. According to Haghighipour, the detection is important because it "indicates that observational techniques are on the right track for finding habitable low-mass rocky planets similar to Earth."[7]

According to its discoverers, HIP 57050 b provides support for the proposition that planet-bearing M-class stars tend to be metal-rich, a correlation already observed in F, G and K-class stars.[6]

At the expected planetary effective temperature, the atmosphere may contain water clouds, potentially detectable by the Hubble Space Telescope if it could capture a planetary transit.[6]

The planet's discoverers speculated about the possibility of a habitable moon:

"By analogy with our own solar system, whose gas giants all have dozens of moons, one might expect HIP 57050 b to also harbor such moons. In our solar system, ∼0.02% of the masses of the gas giants are assigned to their satellites. This would translate to a satellite with ∼2% of Earth's mass (similar to Titan) orbiting HIP 57050 b. While it is not out of the question that HIP 57050 b could harbor a moon, and that moon would thus be in the liquid water HZ of the parent star, an object with only 1/5th of the mass of Mars in the liquid water HZ is probably not a particularly good prospect for habitability from various standpoints. In any case, direct detection of such a moon would be extremely challenging."[6]

Paul Gilster of the Tau Zero Foundation has commented:

"Based on our knowledge of the gas giants in our own Solar System, it’s a natural supposition that this is a world with moons, and if so, their location in the habitable zone draws inevitable comparisons with fictional worlds like Pandora."[8]

Gilster suggested that an Earth-sized moon could exist around the planet if it were captured after forming independently.[8]

A second planet was suspected based on additional radial velocity measurements made at W. M. Keck Observatory, this was confirmed by measurements taken at Calar Alto Observatory.[9]

The HIP 57050 planetary system[9]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥96.70+1.41
−1.02 M⊕		 0.166±0.01 41.380+0.002
−0.001		 0.380+0.010
−0.012		 — —
c ≥68.06+4.91
−2.19 M⊕		 0.912+0.005
−0.002		 532.58+4.14
−2.52		 0.342+0.050
−0.062		 — —
gollark: We use it to get security updates early.
gollark: Oh, they must be using something like the osmarks.tk™ closed timelike curve.
gollark: But they're government-funded-ish, which adds new ones.
gollark: They don't have to make ad revenue, which removes some of the bad incentives.
gollark: Well, the BBC's *allegedly* impartial.

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. "HIP 57050". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-11.
  3. Lépine, Sébastien; et al. (2013). "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky". The Astronomical Journal. 145 (4). arXiv:1206.5991. Bibcode:2013AJ....145..102L. doi:10.1088/0004-6256/145/4/102.
  4. "ARICNS 4C02126". ARICNS. Retrieved 22 January 2017.
  5. Nidever, David L.; et al. (2013). "Radial Velocities for 889 Late-Type Stars". The Astrophysical Journal Supplement Series. 141 (2): 503–522. arXiv:astro-ph/0112477. Bibcode:2002ApJS..141..503N. doi:10.1086/340570.
  6. Nader Haghighipour; Steven S. Vogt; R. Paul Butler; Eugenio J. Rivera; Greg Laughlin; Stefano Meschiari; Gregory W. Henry (2001). "The Lick-Carnegie Exoplanet Survey: A Saturn-Mass Planet in the Habitable Zone of the Nearby M4V Star HIP 57050,". The Astrophysical Journal. 715: 271–276. arXiv:1004.4608. Bibcode:2010ApJ...715..271H. doi:10.1088/0004-637X/715/1/271.
  7. Louise Good (2010). "Planet Detected in Habitable Zone of Nearby Star". Na Kilo Hoku "The Ones Who Look to the Stars", A Newsletter from the Institute of Astronomy. University of Hawai'i.
  8. "Warm 'Saturns' and Their Moons". Centauri Dreams. 11 May 2010.
  9. Trifonov, T.; et al. (2018). "The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems". Astronomy and Astrophysics. 609. A117. arXiv:1710.01595. Bibcode:2018A&A...609A.117T. doi:10.1051/0004-6361/201731442.
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