ROXs 42Bb

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ROXs 42Bb
Exoplanet List of exoplanets
ROXs42Bb image.jpeg
Discovery image for ROXs 42Bb.
Parent star
Star ROXs 42B
Constellation Ophiuchus
Right ascension (α) 16h 31m 15.0s
Declination (δ) −24° 32′ 43.7″
Apparent magnitude (mV) 14.27
Distance 440 ± 16 ly
(135 ± 5 pc)
Spectral type M0V
Age 0.002+.002
Observed separation
Observation epoch 2011 Jun 22
Angular separation (ρ) 1169 ± 5 mas
Position angle (θ) 269.25 ± 0.25°
Projected separation (d) 157 AU
Physical characteristics
Mass (m) 9.0+6
Radius (r) 2.5 RJ
Surface gravity (g) 3.8 ± 0.2 g
Temperature (T) 1,950-2,000 K
Discovery information
Discovery date October 17, 2013
Discoverer(s) Currie et al.[1]
Discovery method Direct imaging
Discovery site Keck Telescope, Very Large Telescope, Subaru Telescope
Discovery status Published[1]

ROXs 42Bb is a directly imaged planetary-mass companion[1] to the binary M star ROXs 42B,[2] a likely member of the Rho Ophiuchi cloud complex. The companion was announced/discovered on October 17, 2013 by University of Toronto astronomer Thayne Currie.

The object has an estimated mass between 6 and 15 Jupiter masses, depending on the age of the star,[1] similar to the masses of directly imaged planets around HR 8799 and beta Pictoris. However, it is unclear whether ROXs 42Bb formed like these planets via core accretion, formed by disk (gravitational) instability, or formed more like a binary star. Preliminary fits of the spectra and broadband photometry to atmospheric models imply an effective temperature of about 2000 K.[3] Like Beta Pictoris b, ROXs 42Bb's atmosphere is likely very cloudy and dusty.[3]


  1. ^ a b c d Currie, Thayne; Daemgen, Sebastian; Debes, John; Lafreniere, David; Itoh, Yoichi; Jayawardhana, Ray; Ratzka, Thorsten; Correia, Serge (2014). "Direct Imaging and Spectroscopy of a Candidate Companion Below/Near the Deuterium-Burning Limit In The Young Binary Star System, ROXs 42B". The Astrophysical Journal Letters. 780: 30. Bibcode:2014ApJ...780L..30C. arXiv:1310.4825Freely accessible. doi:10.1088/2041-8205/780/2/L30. 
  2. ^ Simon, Michael; Ghez, A. M.; Leinert, Ch.; Cassar, L.; Chen, W. P.; Howell, R. R.; Jameson, R. F.; Matthews, K.; Neugebauer, G.; Richichi, A. (1995). "A lunar occultation and direct imaging survey of multiplicity in the Ophiuchus and Taurus star-forming regions". The Astrophysical Journal. 443: 625. Bibcode:1995ApJ...443..625S. doi:10.1086/175554. 
  3. ^ a b Currie, Thayne; Burrows, Adam; Daemgen, Sebastian (2014). "A First-Look Atmospheric Modeling Study of the Young Directly-Imaged Planet-Mass Companion, ROXs 42Bb". arXiv:1404.0131Freely accessible [astro-ph.SR].