ASASSN-V J213939.3-702817.4

Star in the constellation Indus

ASASSN-V J213939.3-702817.4
Observation data Epoch J2000 Equinox J2000
Context star field of ASASSN-V J213939.3-702817.4
Constellation	Indus^[1]
Right ascension	21^h 39^m 39.3^s^[2]
Declination	−70° 28′ 17.4″^[2]
Characteristics
Spectral type	F0V^[3]
Astrometry

Distance	3630±110^[3] ly (1113±33^[3] pc)
Absolute magnitude (M_V)	2.5^[2]

Details

Temperature	6800±110^[3] K

Other designations
2MASS ASAS-SN-V J213939.3-702817.4, J213939.3-702817.4
Database references
SIMBAD	data

ASASSN-V J213939.3-702817.4 (also known as ASAS-SN-V J213939.3-702817.4 and J213939.3-702817.4) is a star, previously non-variable, found to be associated with an unusual, deep dimming event that was uncovered by the All Sky Automated Survey for SuperNovae (ASAS-SN) project, and first reported on 4 June 2019 in The Astronomer's Telegram.^[2]^[3]^[4]

The star, in the constellation of Indus, about 3,630 ± 110 light-years (1,113 ± 33 pc)^[3]^[5] away, was first observed on 15 May 2014 (UT) by ASAS-SN, and, as of 4 June 2019, has resulted in more than 1780 data points, including a quiescent mean magnitude of g~12.95.^[2] On 4 June 2019, the star was reported to have dimmed gradually from g~11.96 at HJD 2458635.78, to g~14.22 at 4458837.45, and, as of 4 June 2019, seems to be returning to its quiescent state of g~13.29 at HJD 2851634.89.^[2] According to astronomer Tharindu Jayasinghe, one of the discoverers of the deep dimming event, "[The star has] been quiescent for so long and then suddenly decreased in brightness by a huge amount ... Why that happened, we don't know yet."^[4]

References

^ Staff (2 August 2008). "Finding the constellation which contains given sky coordinates". DJM.cc. Retrieved 8 June 2019.
^ ^a ^b ^c ^d ^e ^f Jayasinghe, T.; et al. (4 June 2019). "ASAS-SN Discovery of an Unusual, Deep Dimming Episode of a Previously Non-Variable Star". The Astronomer's Telegram. Retrieved 8 June 2019.
^ ^a ^b ^c ^d ^e ^f McCollum, B.; Laine, S. (8 June 2019). "Spectral Type of the Unusual Variable ASASSN-V J213939.3-702817.4". The Astronomer's Telegram. Retrieved 8 June 2019.
^ ^a ^b Seidel, Jamie (6 June 2019). "A suddenly dimming star has caught the attention of alien hunters". The Advertiser. Retrieved 8 June 2019.
^ Gilster, Paul (5 June 2019). "HD 163296: Emerging Insights into Circumstellar Disks - Comment (Harry R Ray on 5 June 2019, 9:56)". Centauri-Dreams.org. Retrieved 8 June 2019.

External links

Video (13:46) − "Tabby's Star" on YouTube, a presentation by Tabetha S. Boyajian (2016).
Video (31:00) − "Tabby's Star" on YouTube, a presentation by Issac Arthur (2016).
Video (01:00) − RZ Piscium on YouTube, star with unusual light fluctuations (2017).
Video (00:13) – EPIC 204376071 on YouTube, up to 80% dimming (2019).

Constellation of Indus

Stars

Bayer	α (the Persian) β γ δ ε ζ η θ ι κ¹ κ² μ ο π ρ
Variable	T
HR	8269 8331
Other	ASASSN-V J213939.3-702817.4 LHS 3844 WASP-46 WASP-88