 Ross 19A (bright star) and Ross 19B (marked with a blue cross-hair) Credit:NASAWISE & unWISE (Meisner et al. 2022) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Triangulum |
| Ross 19A | |
| Right ascension | 02h 19m 03.0092s |
| Declination | +35° 21′ 18.601″ |
| Apparent magnitude (V) | 12.70[1] |
| Ross 19B | |
| Right ascension | 02h 19m 48.68s |
| Declination | +35° 18′ 45.3″ |
| Characteristics | |
| Evolutionary stage | red dwarf + brown dwarf |
| Spectral type | M3.5[1] + T9-Y0[2] |
| Astrometry | |
| Ross 19A | |
| Radial velocity (Rv) | −27.80 ± 0.14 km/s |
| Proper motion (μ) | RA: 670.532 ± 0.042mas/yr[3] Dec.: −427.412 ± 0.040mas/yr[3] |
| Parallax (π) | 57.3276±0.0398 mas[3] |
| Distance | 56.89 ± 0.04 ly (17.44 ± 0.01 pc) |
| Ross 19B | |
| Proper motion (μ) | RA: 673.2 ± 46.4 mas/yr[3] Dec.: −504.4 ± 57.0 mas/yr[3] |
| Distance | 17.58 ± 3.75[3] pc |
| Details[3] | |
| Ross 19A | |
| Mass | 0.362 ± 0.007 M☉ |
| Radius | 3.38 ± 0.03 RJup |
| Temperature | 3481 ± 49 K |
| Metallicity [Fe/H] | −0.40 ± 0.12 dex |
| Age | 7.2+3.8 −3.6 Gyr |
| Ross 19B | |
| Mass | 15–40 MJup |
| Temperature | 500+115 −100 K |
| Position (relative to Ross 19A)[3] | |
| Component | Ross 19B |
| Angular distance | 568″ |
| Projected separation | 9900AU |
| Other designations | |
| Ci 20 165,GJ 94,LHS 1388, NLTT 7619, LTT 10785,G 74-14, G 134-26, LSPM J0219+3521,2MASS J02190305+3521181, WISEA J021903.58+352114.1 | |
| Ross 19B: CWISE J021948.68+351845.3 | |
| Database references | |
| Ross 19A | |
| SIMBAD | data |
| Ross 19B | |
| SIMBAD | data |
Ross 19 is ared dwarf of spectral type M3.5.[1] In 2021 it was discovered that Ross 19 has a companion, which is a coldbrown dwarf. Ross 19B is likely the coldest brown dwarf found around amain-sequence star, as of July 2024.[3]
Ross 19A was discovered in 1925 byFrank E. Ross as a proper-motion star with the help of theYerkes Observatory and archived plates byE. E. Barnard.[4] In 1985 the first spectral information was published by W. P. Bidelman, based on observations byG. P. Kuiper, which reported the star to have a V magnitude of 12.70 and a spectral type of M3.5.[1] In 2020 the star was observed at theLick Observatory and withIRTF. Ross 19A has a mass of about 0.36M☉ and has an age between 3.6 and 11 billion years. It has a sub-solarmetallicity and has a temperature of about 3500Kelvin. InTESS andZTF light curves it does not show anyvariability and does not show anyflares.[3]
Ross 19B (also called CWISE J021948.68+351845.3) was initially found in theBackyard Worlds project by thecitizen scientists Samuel Goodman, Léopold Gramaize, Austin Rothermich, and Hunter Brooks. It was then observed by the professional astronomers of the paper led byAdam C. Schneider with theKeck Observatory in 2020, measuring a J-band magnitude of 21.14 ± 0.02. The researchers calculated that Ross 19B has a 100% probability to be bound to Ross 19A. Ross 19B has a very low temperature of about 400–615kelvins (127–342 °C; 260–647 °F), making it either a lateT-dwarf or aY-dwarf. It has a mass between 15 and 40MJ, making it a brown dwarf. Its wide separation results in an extremely lowgravitational binding energy. It is suggested that Ross 19B has a sub-solar metallicity similar to the red dwarf.[3] Later observation withGemini North showed a Y-band magnitude of 21.86 ± 0.06. This showed that the spectral type is likely between T9 and Y0.[2] AJWST program is dedicated to observe Ross 19B in Cycle 3.[5]
