Hen 2-251

CONFIRMED MILKY WAY

Constellation
Ophiucus

Equatorial coordinates
α = 17 35 22.232
δ = -29 45 19.894

Galactic coordinates
l = 358.1205°
b = 1.4588°

Suspected	1987^Ref
Confirmed	1987^Ref
Symbiotic IR type	D^Ref
Hot component type	shell-burning^Ref
Outbursts	-

Identifiers

Hen 2-251	IRAS 17321-2943	GSC2.4.2 S8H0265936	AAVSO 000-BLC-802
SIMBAD PN H 1-25	Pan-STARRS 72292638426293651	SAO -	VSX 61207
GAIA DR3 4058561820720486272	SkyMapper 173522.23-294519.6	WRAY 16-289	GCVS -
2MASS J17352223-2945198	HIP -	Hen 2-251	BD -
WISE J173522.22-294519.7	TYC -	ESO 455-22	HD -

Symbiotic Catalogs

Bidelman (1954)	-	Allen (1984)	-	Belzcyński et al. (2001)	Hen 2-251 (Conf.)
Gaposchkin (1957)	-	Kenyon (1986)	-	Akras et al. (2019)	Hen 2-251 (Conf.)
Boyarchuk (1969)	-	Vaidis (1988, 1991)	H-1-25 (Susp.)

Position

Right ascension (°)	263.8426^Ref	Parallax (mas)	0.043±0.075^Ref	Reddening E(B-V) (mag)	2.15±0.13^Ref ^{, Note}
Declination (°)	-29.7555^Ref	Distance (kpc)	8.5^Ref 8.86^Ref ^{, Note}, 5.74^Ref ^{, Note}
Galactic longitude (°)	358.1205^Ref	Proper motion in α (mas/yr)	-6.03±0.09^Ref
Galactic latitude (°)	1.4588^Ref	Proper motion in δ (mas/yr)	0.87±0.06^Ref

Observations

X-Ray	No^Ref	IR type	D^Ref	Radio	No^Ref
X-Ray type	-	J (mag)	10.42^Ref	Flickering	-
GALEX FUV (mag)	-	H (mag)	8.63^Ref	Outbursts	-
GALEX NUV (mag)	-	K (mag)	6.95^Ref	Outburst type	-
IUE	No^Ref	WISE W1 (mag)	4.63^Ref	Jets	-
FUSE	No^Ref	WISE W2 (mag)	3.61^Ref	Resolved nebula	-
U (mag)	-	WISE W3 (mag)	1.72^Ref	IPmax (eV)	114^Ref
B (mag)	-	WISE W4 (mag)	0.30^Ref	[O III] lines	Yes^Ref
V (mag)	15.70^Ref	IRAS 12μm (Jy)	7.33^Ref	He II lines	Yes^Ref
R (mag)	-	IRAS 25μm (Jy)	7.46^Ref	[Fe VII] lines	Yes^Ref
I (mag)	-	IRAS 60μm (Jy)	2.54^Ref	O VI lines	Yes^Ref
BP (mag)	16.87^Ref	IRAS 100μm (Jy)	75.30^Ref
G (mag)	15.81^Ref	AKARI S09 (Jy)	-
RP (mag)	14.59^Ref	AKARI S18 (Jy)	5.69^Ref

Orbit

Orbital period (days)	-	γ velocity (km/h)	-	Size of giant’s orbit (AU)	-
Eccentricity	-	RV of giant (km/h)	-	Separation (AU)	-
Inclination (°)	-	Inferior conj. of giant (JD)	-	Mass function	-
Eclipses	-			Mass ratio	-
Orbital ephemeris	-

Cool component

Spectral type	K5^Ref, late M^Ref	Mass (M_⊙)	-	Pulsation	-
Eff. temperature (K)	-	Radius (R_⊙)	-	Type	-
IR type	D^Ref	Luminosity (L_⊙)	-	Pulsation period (days)	-
Metallicity [Fe/H]	-			Pulsation ephemeris	-

Hot component

Type/Spectral type	WD^Ref	Mass (M_⊙)	-	Spin period (min)	-
Shell-burning/Accreting-only	shell-burning^Ref	Radius (R_⊙)	-	Accretion disk	-
Eff. temperature (K)	-	Luminosity (L_⊙)	5700^Ref
Lower limit (K)	114000^Ref
Upper limit (K)	-

Links

SIMBAD CDS Portal

Notes

Initially suspected in Acker et al. (1992), the symbiotic nature of this star was confirmed by the detection of strong O VI lines by Stenholm & Acker (1987) and Cieslinski et al. (1994).

References

Acker, A., Marcout, J., Ochsenbein, F. et al., 1992, The Strasbourg-ESO Catalogue of Galactic Planetary Nebulae. Parts I, 1, 1992secg.book.....A
Cieslinski, D., Elizalde, F., Steiner, J. E., 1994, A&AS, 106, 243, 1994A&AS..106..243C
Mikołajewska, J., Acker, A., Stenholm, B., 1997, A&A, 327, 191, 1997A&A...327..191M
Stenholm, B., Acker, A., 1987, A&AS, 68, 51, 1987A&AS...68...51S

Last updated: April 14, 2022