astro.wikisort.org - Star

Elias 2-27 (2MASS J16264502-2423077)[1] is a YSO star[1] with a protoplanetary disk around it, located in the Ophiuchus Molecular Cloud (ρ Oph Cld, 5 Oph Cld, Ophiuchus Dark Cloud), a star-forming region in the Ophiuchus constellation, some 450 light-years (140 parsecs) away. This star system became the first ever observed with density waves in the disk, giving it a spiral structure. Elias 2-27 is located near the double star Rho Ophiuchi (5 Ophiuchi).[3][4]

Elias 2-27

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Ophiuchus
Right ascension	16h 26m 45.025s[1]
Declination	−24° 23′ 07.75″[1]
Apparent magnitude (V)	13.32[1]
Characteristics
Evolutionary stage	Pre-main-sequence star
Spectral type	M0[1]
Astrometry
Distance	378 ly (116+19 −10[2] pc)
Details[2]
Mass	0.46+0.02 −0.03 M☉
Radius	2.3 R☉
Temperature	3850 K
Age	0.8 Myr
Other designations
Gaia DR2 6049161819498750208, 2MASS J16264502-2423077[1]
Database references
SIMBAD	data

Disk

In 2016, it was discovered that disk perturbations from density waves organized the disk debris into a pinwheel structure, with sweeping spiral arms; using observations from the Atacama Large Millimeter Array (ALMA) radio telescope. This marks the first instance of such an observation in a protoplanetary disk, though they have been previously predicted. The spiral arms start at 100 AU (9.3×10⁹ mi; 1.5×10¹⁰ km) and extend out to 300 AU (2.8×10¹⁰ mi; 4.5×10¹⁰ km).[6][3] The disk has a 14 AU wide gap at 69 AU radius with a reduced amount of dust.[2] The disk is very massive at 0.08±0.04M_☉.[7]

The planetary system[2]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
protoplanetary disk	5–300 AU				56.2±0.8°	—

Further reading

• Laura M. Pérez; et al. (2016). "Spiral density waves in a young protoplanetary disk". Science (published 30 September 2016). 353 (6307): 1519–1521. arXiv:1610.05139. Bibcode:2016Sci...353.1519P. doi:10.1126/science.aaf8296. PMID 27708098. S2CID 38667381.

References

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