HIP 99770 b

Last updated

HIP 99770 b
HIP 99770 b.png
Subaru Telescope detection of HIP 99770 b
Discovery
Discovered by Currie et al. [1]
Discovery site Subaru Telescope
Discovery dateNovember 30, 2022
Direct imaging
Orbital characteristics [2]
15.7+3.5
−1.0 AU
Eccentricity 0.31+0.06
−0.12 [3]
47+14
−4 years
Inclination 151.3+8.4
−12.0 °
279°+72°
−269°
2,465,218+3,763
−771 JD
250°+68°
−218°
Star HIP 99770
(29 Cygni)
Physical characteristics
1.056 [2] RJ
Mass 13.1+4.8
−5.2 [2] MJ
Temperature 1,300 [2] K
Spectral type
L8 [3]

    HIP 99770 b is a directly imaged planet [1] [2] [4] orbiting the A-type star HIP 99770 (29 Cygni), detected with Gaia/Hipparcos precision astrometry and high-contrast imaging. [5] HIP 99770 b is the first joint direct imaging + astrometric discovery of an extrasolar planet and the first planet discovered using precision astrometry from the Gaia mission. [1]

    Contents

    Discovery

    HIP 99770 b was discovered by a team led by Thayne Currie, Mirek Brandt, and Tim Brandt using the Subaru Telescope on Mauna Kea. The Subaru data utilized the observatory's extreme adaptive optics system, SCExAO, to correct for atmospheric turbulence and the CHARIS integral field spectrograph to detect HIP 99770 b at 22 different near-infrared wavelength passbands from 1.1 microns to 2.4 microns. It was also detected at longer wavelengths using the NIRC2 camera on the Keck Observatory. [1]

    Characteristics

    The orbit of HIP 99770 b has been measured using both absolute astrometry of 29 Cygni as measured by Gaia and Hipparcos, [1] and its relative astrometry (location with respect to the host star) from VLTI/GRAVITY [3] and SCExAO/CHARIS. [2] The most recent orbital solution give an orbital period of 47 years, a semi-major axis of 15.8  astronomical units, an orbital eccentricity of 0.29, and an inclination of 151°. [2] As the host star is significantly more luminous than the Sun, HIP 99770 b receives roughly as much light as Jupiter receives from the Sun. [1] Atmospheric modelling give a temperature of about 1,300  K and a radius of 1.056 RJ. [2] With a spectral type of L8, [3] HIP 99770 b lies at L/T transition for substellar objects, from cloudy atmospheres without methane absorption to clear atmospheres with methane absorption. The companion is likely intermediate in cloudiness and gravity between older, more massive field brown dwarfs and young L/T transition exoplanets like HR 8799 d. [1] [2]

    The mass of HIP 99770 b is directly measured from joint dynamical modeling of the planet's relative astrometry from direct imaging data and absolute astrometry of the host star. The most recent mass estimates range between 13.1 MJ and 15.0 MJ [2] . Thus HIP 99770 b likely straddles the deuterium burning limit, and as of such it has been considered a super-Jupiter [3] . While the deuterium burning limit has often been used as a mass criterion to distinguish between planets and brown dwarfs, the discovery paper showed that HIP 99770 b's mass and mass ratio (mass divided by the mass of the host star) were instead better consistent with values for planets than brown dwarfs [1] . HIP 99770 b appears to have a moderate eccentricity of e ~ 0.3: more eccentric than most directly imaged planets with well-constrained orbits but broadly consistent with the either planets or brown dwarf population. Its relatively small orbital separation and location near the system's ice line suggests it may have formed in a protoplanetary disk.

    See also

    References

    1. 1 2 3 4 5 6 7 8 Currie, Thayne; Brandt, G. Mirek; Brandt, Timothy D.; Lacy, Brianna; Burrows, Adam; Guyon, Olivier; Tamura, Motohide; Liu, Ranger Y.; Sagynbayeva, Sabina; Tobin, Taylor; Chilcote, Jeffrey; Groff, Tyler; Marois, Christian; Thompson, William; Murphy, Simon J. (April 14, 2023), "Direct imaging and astrometric detection of a gas giant planet orbiting an accelerating star", Science, 380 (6641): 198–203, arXiv: 2212.00034 , Bibcode:2023Sci...380..198C, doi:10.1126/science.abo6192, ISSN   0036-8075
    2. 1 2 3 4 5 6 7 8 9 10 Bovie, Danielle; Currie, Thayne; Morsy, Mona El; Lacy, Brianna; Kuzuhara, Masayuki; Chilcote, Jeffrey; Tobin, Taylor; Guyon, Olivier; Groff, Tyler (September 2, 2025), "Multi-band Spectral and Astrometric Characterization of the HIP 99770 b Planet with SCExAO/CHARIS and Gaia", The Astronomical Journal, arXiv: 2509.02665
    3. 1 2 3 4 5 Winterhalder, T. O.; Kammerer, J.; Lacour, S.; Mérand, A.; Nowak, M.; Stolker, T.; Balmer, W. O.; Marleau, G.-D.; Abuter, R.; Amorim, A.; Asensio-Torres, R.; Berger, J.-P.; Beust, H.; Blunt, S.; Bonnefoy, M. (June 27, 2025), "Orbit and atmosphere of HIP 99770 b through the eyes of VLTI/GRAVITY", Astronomy & Astrophysics, arXiv: 2507.00117 , doi:10.1051/0004-6361/202554766, ISSN   0004-6361
    4. ↑ "HIP 99770 Overview". NASA Exoplanet Archive.
    5. ↑ Andrew Jones (April 17, 2023), "Giant exoplanet found, imaged directly thanks to star-mapping data (photos)", Space.com

    Further reading

    This page is based on this Wikipedia article
    Text is available under the CC BY-SA 4.0 license; additional terms may apply.
    Images, videos and audio are available under their respective licenses.