EPIC 204278916 is a pre-main-sequence star, about five million years old with a spectral type of M1, implying a red dwarf. It is part of the Upper Scorpius sub-group of the Scorpius–Centaurus association, and is in the constellation Scorpius. The star is approximately the size of the Sun at 0.97 R☉, but is only half its mass (0.50 M☉) and a fraction of its luminosity (0.15 L☉).[5]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 16h 02m 07.576s[1] |
| Declination | −22° 57′ 46.89″[1] |
| Characteristics | |
| Evolutionary stage | Pre-main-sequence |
| Spectral type | M1[2] |
| Apparent magnitude (R) | 13.7[3] |
| J−H color index | 0.712 |
| J−K color index | 1.033 |
| Astrometry | |
| Proper motion (μ) | RA: -12.267±0.123 mas/yr Dec.: -24.955±0.069 mas/yr |
| Parallax (π) | 7.1285 ± 0.0633 mas[4] |
| Distance | 458 ± 4 ly (140 ± 1 pc) |
| Details | |
| Mass | 0.5[5] M☉ |
| Radius | 0.97[5] R☉ |
| Luminosity (bolometric) | 0.15[3] L☉ |
| Temperature | 3,673[3] K |
| Age | ≈5[5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This stellar object was first characterized by the 2nd USNO CCD Astrograph Catalog and the Two Micron All-Sky Survey,[1][6] and was further studied during the Kepler space telescope's extended K2 mission Campaign 2 between 23 August and 13 November 2014.
Luminosity
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In August 2016, a team of astronomers, led by Simone Scaringi of the Max Planck Institute for Extraterrestrial Physics in Germany, reported that this red dwarf star has a resolved circumstellar disc. Further, the research team observed unusual luminosity dimmings of up to 65% for 25 consecutive days (out of 79 total observation days). The variability in luminosity was highly periodic and attributed to stellar rotation. The researchers hypothesized that the irregular dimmings were caused by either a warped inner-disk edge or transiting cometary-like objects in either circular or eccentric orbits.[5]
See also
editReferences
edit- ^ a b c Zacharias, N.; Urban, S. E.; Zacharias, M. I.; et al. (2003). "VizieR Online Data Catalog: The Second U.S. Naval Observatory CCD Astrograph Catalog (UCAC2)". CDS/ADC Collection of Electronic Catalogues (1289). Bibcode:2003yCat.1289....0Z.
- ^ Bouy, H.; Martín, Eduardo L. (September 2009). "Proper motions of cool and ultracool candidate members in the Upper Scorpius OB association". Astronomy and Astrophysics. 504 (3): 981–990. arXiv:0907.0149. Bibcode:2009A&A...504..981B. doi:10.1051/0004-6361/200811088. S2CID 14150392.
- ^ a b c Preibisch, Thomas; Brown, Anthony G. A.; Bridges, Terry; Guenther, Eike; Zinnecker, Hans (July 2002). "Exploring the Full Stellar Population of the Upper Scorpius OB Association". The Astronomical Journal. 124 (1): 404–416. Bibcode:2002AJ....124..404P. doi:10.1086/341174.
- ^ 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.
- ^ a b c d e f Scaringi, S.; Manara, C. F.; Barenfeld, S. A.; Groot, P. J.; Isella, A.; et al. (August 2016). "The peculiar dipping events in the disk-bearing young-stellar object EPIC 204278916". Monthly Notices of the Royal Astronomical Society. 463 (2). stw2155. arXiv:1608.07291. Bibcode:2016MNRAS.463.2265S. doi:10.1093/mnras/stw2155. S2CID 8188464.
- ^ Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
