List of stars that have unusual dimming periods

This list contain stars that had periods when their apparent magnitude dropped in a way that is not typical of any class of variable stars. Most of these dimming events happened due to an occultation by a dust cloud or dust disk, but many remain without explanation.

Artist's concept of an "uneven ring of dust" orbiting KIC 8462852, also known as Tabby's Star

List

Tabby's Star (KIC 8462852) – Consolidated plot of all known dimmings (1 March 2020)

Star designation	Stellar class	Magnitude		Right ascension (J2000)	Declination (J2000)	Distance (light-years)	Reason for dimming
		Apparent	Absolute
ASASSN-V J193622.23+115244.1	—	14.0–15.5[1]	—	19h 36m 22.23s[1]	+11° 52′ 44.1″[1]	6592[1]	Unknown
ASASSN-V J213939.3-702817.4	F0V[2]	12.95–14.22[3]	2.5[3]	21h 39m 39.3s[3]	−70° 28′ 17.4″[3]	3630[2]	Unknown
Betelgeuse	M1-2[4]	+0.50[5]	—	05h 55m 10.30536s[6]	+07° 24′ 25.4304″[6]	—	"large-grain circumstellar dust"[7][8]
EPIC 204278916	M1[9]	13.7[10]	—	16h 02m 07.576s[11]	−22° 57′ 46.89″[11]	—	Dust disk
EPIC 204376071	M[12]	—	—	16h 04m 10.1267s[13]	−22° 34′ 45.5503″[13]	440[12]	Possibly giant planet or brown dwarf with rings
HD 139139 (EPIC 249706694)	G3/5V	9.84;[14] 9.677[15]	—	15h 37m 06.215s[15]	−19° 08′ 32.96″[15]	350[16] 572[15]	Unknown. It is possible that it didn't had a dimming event at all, and the observed dimmings were due to instrumental errors.
KH 15D	K7[17]	15.5–21.5[18]	6.226[19]	06h 41m 10.31s[20]	+09° 28′ 33.2″[20]	773[21]	Possibly circumbinary disk
KIC 4150611 (HD 181469)	Pulsator/K/M/G	—	—	19h 18m 58.21759s[22]	+39° 16′ 01.7913″[22]	—	Five-star system
PDS 110	keF6 IVeb[23]	10.422[23]	2.54[23]	05h 23m 31.008s[23]	–01° 04′ 23.68″[23]	1090[23]	Possibly eclipses by circumstellar dust[24]
RW Cephei	K2 0-Ia[25]	6.0–7.6[26]	—	22h 23m 07.01521s[27]	+55° 57′ 47.6244″[27]	11,000[28][a]	Great dimming event similar to Betelgeuse
RZ Piscium	K0 IV[29]	11.29–13.82[29]	—	01h 09m 42.056s[30]	+27° 57′ 1.95″[30]	550[31]	Substantial mass of gas and dust, possibly from disrupted planet
Tabby's Star (KIC 8462852)	F3V[32][33]	11.705[33]	3.08[32]	20h 06m 15.4527s[32]	+44° 27′ 24.791″[32]	1470[32]	Unknown
TIC 400799224	—	—	—	—	—	—	"probably from an orbiting body that periodically emits clouds of dust that occult the star"[34][35]
V1400 Centauri	K5 IV(e) Li[36]	12.31[36]	—	14h 07m 47.93s[36]	−39° 45′ 42.7″[36]	434[37]	Eclipse by a free-floating brown dwarf or rogue planet with a circumstellar disk or ring system[38]
VVV-WIT-07	—	14.35–16.164[39]	—	17h 26m 29.387s[39]	−35° 40′ 6.20″[39]	23000/?[39]	Unknown
WD 1145+017 (EPIC 201563164)	DB[40]	17.0[41]	—	11h 48m 33.63s[40]	+01° 28′ 59.4″[40]	570[42]	Dust disk
ZTF J0139+5245 (ZTF J013906.17+524536.89)	DA[43]	18.4[43]	—	01h 39m 06.17s	+52° 45′ 36.89″	564[43]	Dust disk
Gaia17bpp	M0-III	16.13–20.48[44]	—	19h 37m 23.16s	+17° 59′ 02.90″	27,600[45]	Dust disk
Gaia21bcv	K4.5V	17.70–20.12	3.2	07h 14m 33.276s	−12° 13′ 27.34″	4,508	Eclipse by a substellar companion with a 0.5 AU-radius debris disk[46]
ASASSN-21js	B[b]	12.8	1.38	11h 47m 11.754s	−62° 10′ 36.80″	9,149	Eclipse by a distant substellar companion with a 1.05 AU-radius debris disk[47]
WD 1054–226	DAZ	16.0	—	10h 56m 38.63s	−22° 52′ 56.08″	118	Debris disc[48]

See also

• BD+20°307
• Disrupted planet
• Ecliptic Plane Input Catalog (EPIC)
• Gaia16aye
• List of transiting circumsecondary disks
• Lists of astronomical objects
• List of semiregular variable stars
• Lists of stars
• List of variable stars
• Search for extraterrestrial intelligence
• WD 0145+234 (star disrupting an exoasteroid)

Notes

1. Assuming membership to Cepheus OB1
2. ASASSN-21js's temperature of 14800+4200
   −2800 K lies within the temperature range for B-type main-sequence stars.^[47]