Astronomy:EPIC 204376071

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Short description: Star noted for unusual dimming events
EPIC 204376071
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Context star field of EPIC 204376071
Observation data
Equinox J2000.0]] (ICRS)
Constellation Scorpius[1]
Right ascension  16h 04m 10.1267s[2]
Declination −22° 34′ 45.550″[2]
Apparent magnitude (V) 18.0[3]
Characteristics
Evolutionary stage M[4]
Astrometry
Proper motion (μ) RA: −11.544[2] mas/yr
Dec.: −24.892[2] mas/yr
Parallax (π)7.3908 ± 0.1944[2] mas
Distance440 ± 10 ly
(135 ± 4 pc)
Details
Mass0.161±0.028[4][5] M☉
Radius0.631±0.042[5] R☉
Luminosity (bolometric)0.0273±0.0020[4] L☉
Temperature2960±75[4] K
Rotation1.63 days[6]
Age10[7] Myr
Other designations
UScoCTIO 48, 2MASS J16041012-2234453[2]
Database references
SIMBADdata

EPIC 204376071 is an M-type star in the constellation of Scorpius. Parallax measurements by the Gaia space observatory put the star at a distance of about 440 light-years (130 parsecs) from Earth.[4][5][7] It is likely a member of the Upper Sco association, and is young enough that it has not yet become a main-sequence star.[4]

A light curve for EPIC 204376071, adapted from Rappaport et al. (2019).[5] The inset plot shows the time around the dimming with an expanded scale.

Unusual light fluctuations of the star, including up to an 80% dimming in brightness (i.e., "single 80% deep occultation of 1-day duration"), were observed by astronomers.[5][7] The unusual dimming was not only extremely deep, but also substantially asymmetric, with an egress about twice as long as the ingress.[6] Nonetheless, such an unusual dimming for EPIC 204376071 is much greater than the 22% dimming observed for Tabby's star.[8][9] Several explanations have been presented to explain the unusual dimming of the EPIC 204376071 star: one, orbiting dust or small particles; or two, a "transient accretion event of dusty material near the corotation radius of the star".[5] The unusual light curve of the star is similar to the light curve of a candidate exoplanet, KIC 10403228 b, which may have been caused by a "tilted ring system" orbiting the planet. In the case of EPIC 204376071, an orbiting brown dwarf or large planet, with a ring system, could cause a similar light curve, according to the researchers.[7]

Artist's concept of dust or small particles orbiting a star.

See also

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R  Constellation record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Staff (2019). "EPIC 204376071 -- Star in Association". SIMBAD. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=EPIC%20204376071. 
  3. ↑ Girard, Terrence M.; Van Altena, William F.; Zacharias, Norbert; Vieira, Katherine; Casetti-Dinescu, Dana I.; Castillo, Danilo; Herrera, David; Lee, Young Sun et al. (2011). "The Southern Proper Motion Program. IV. The SPM4 Catalog". The Astronomical Journal 142 (1): 15. doi:10.1088/0004-6256/142/1/15. Bibcode: 2011AJ....142...15G. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Rappaport, S. (22 February 2019). "Deep Long Asymmetric Occultation in EPIC 204376071". Monthly Notices of the Royal Astronomical Society 485 (2): 2681–2693. doi:10.1093/mnras/stz537. Bibcode: 2019MNRAS.485.2681R. http://orbit.dtu.dk/files/169254901/stz537.pdf. Retrieved 6 March 2019. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Rappaport, S. (22 February 2019). "Deep Long Asymmetric Occultation in EPIC 204376071". Monthly Notices of the Royal Astronomical Society 485 (2): 2681–2693. doi:10.1093/mnras/stz537. Bibcode: 2019MNRAS.485.2681R. 
  6. ↑ 6.0 6.1 Nowakowski, Tomasz (5 March 2019). "Astronomers detect deep, long asymmetric occultation in a newly found low-mass star". Phys.org. https://phys.org/news/2019-03-astronomers-deep-asymmetric-occultation-newly.html. 
  7. ↑ 7.0 7.1 7.2 7.3 Starr, Michelle (6 March 2019). "Astronomers Have Discovered Another Mysterious Dimming Star, And It's Even More Epic". ScienceAlert.com. https://www.sciencealert.com/tabby-s-star-has-a-friend-there-s-another-weird-mystery-star-in-town. 
  8. ↑ Carpineti, Alfredo (6 March 2019). "We've Just Found Another Mysteriously Dimming Star In The Galaxy". IFLScience.com. https://www.iflscience.com/space/weve-just-found-another-mysteriously-dimming-star-in-the-galaxy/. 
  9. ↑ Valdez, Rubi (8 March 2019). "Another Dimming EPIC Star Is Likely An Alien Planet, Astronomers Say". Tech Times. https://www.techtimes.com/articles/239240/20190308/another-dimming-epic-star-is-likely-an-alien-planet-astronomers-say.htm. 

Coordinates: Sky map 16h 04m 10.1267s, −22° 34′ 45.5503″



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