RW Hya

Constellation
Hydra

Equatorial coordinates
α = 13 34 18.108
δ = -25 22 48.670

Galactic coordinates
l = 314.9926°
b = 36.4857°

Suspected	1932^Ref
Confirmed	1950^Ref
Symbiotic IR type	S^Ref
Hot component type	shell-burning^Ref
Outbursts	-

Identifiers

RW Hya	IRAS 13315-2507	GSC2.4.2 S6KH000359	AAVSO 000-BCW-104
SIMBAD V* RW Hya	Pan-STARRS 77542035755084069	SAO 81760	VSX 15974
GAIA DR3 6191401382471531264	SkyMapper -	WRAY -	GCVS RW Hya
2MASS J13341813-2522489	HIP -	Hen 3-917	BD -
WISE J133418.11-252248.6	TYC 6718-1146-1	ESO -	HD 117970

Symbiotic Catalogs

Bidelman (1954)	RW Hya (Conf.)	Allen (1984)	RW Hya (Conf.)	Belzcyński et al. (2001)	RW Hya (Conf.)
Gaposchkin (1957)	RW Hya (Conf.)	Kenyon (1986)	RW Hya (Conf.)	Akras et al. (2019)	RW Hya (Conf.)
Boyarchuk (1969)	RW Hya (Conf.)	Vaidis (1988, 1991)	RW Hya (Conf.)

Position

Right ascension (°)	203.5754^Ref	Parallax (mas)	0.648±0.035^Ref	Reddening E(B-V) (mag)	0.06±0.0^Ref ^{, Note}
Declination (°)	-25.3802^Ref	Distance (kpc)	1.3^Ref, 0.6^Ref, 1.0^Ref, 0.67^Ref, 0.82±0.112^Ref 1.48^Ref ^{, Note}, 1.49^Ref ^{, Note}
Galactic longitude (°)	314.9926^Ref	Proper motion in α (mas/yr)	-17.83±0.03^Ref
Galactic latitude (°)	36.4857^Ref	Proper motion in δ (mas/yr)	13.21±0.02^Ref

Observations

X-Ray	No^Ref	IR type	S^Ref	Radio	Yes^Ref
X-Ray type	-	J (mag)	5.73^Ref	Flickering	No^Ref
GALEX FUV (mag)	-	H (mag)	4.92^Ref	Outbursts	-
GALEX NUV (mag)	13.64^Ref	K (mag)	4.61^Ref	Outburst type	-
IUE	Yes^Ref	WISE W1 (mag)	4.57^Ref	Jets	-
FUSE	Yes^Ref	WISE W2 (mag)	4.34^Ref	Resolved nebula	No^Ref
U (mag)	-	WISE W3 (mag)	4.28^Ref	IPmax (eV)	54.4^Ref, 77.5 (UV)^Ref
B (mag)	10.31^Ref	WISE W4 (mag)	3.73^Ref	[O III] lines	Yes^Ref
V (mag)	10.00^Ref	IRAS 12μm (Jy)	0.88^Ref	He II lines	Yes^Ref
R (mag)	-	IRAS 25μm (Jy)	0.45^Ref	[Fe VII] lines	No^Ref
I (mag)	-	IRAS 60μm (Jy)	0.40^Ref	O VI lines	No^Ref
BP (mag)	9.04^Ref	IRAS 100μm (Jy)	1.06^Ref
G (mag)	8.12^Ref	AKARI S09 (Jy)	0.94^Ref
RP (mag)	7.14^Ref	AKARI S18 (Jy)	0.29^Ref

Orbit

Orbital period (days)	372.45±0.3^Ref, 370.2±0.9^Ref, 370.4±0.8^Ref	γ velocity (km/h)	12.4±0.3^Ref, 12.9±0.4^Ref	Size of giant’s orbit (AU)	0.3^Ref
Eccentricity	0±-^Ref	RV of giant (km/h)	8.8±0.5^Ref, 8.8±0.4^Ref	Separation (AU)	1.29±0.08^Ref
Inclination (°)	90^Ref	Inferior conj. of giant (JD)	2445071.6	Mass function	0.019^Ref, 0.026^Ref, 0.026^Ref
Eclipses	Yes^Ref			Mass ratio	3.3^Ref
Orbital ephemeris	Max (pg) = 2421519.2±4.2 + 372.45±0.3 x E^Ref

Cool component

Spectral type	M2 III^Ref, M0 III^Ref, M1.1 III^Ref, M2 III^Ref	Mass (M_⊙)	0.5-2^Ref, 1.6±0.3^Ref, 3.4^Ref	Pulsation	-
Eff. temperature (K)	3770±50^Ref, 3800^Ref, 3655±80^Ref, 3900^Ref	Radius (R_⊙)	83^Ref, 70^Ref, 58.5±8^Ref, 145^Ref	Type	-
IR type	S^Ref	Luminosity (L_⊙)	602^Ref, 1000^Ref, 625±200^Ref, 650±180^Ref	Pulsation period (days)	-
Metallicity [Fe/H]	-0.76±0.06^Ref, -0.64±0.14^Ref, -0.77±0.08^Ref			Pulsation ephemeris	-

Hot component

Type/Spectral type	WD^Ref	Mass (M_⊙)	0.3-0.6^Ref, 0.48±0.06^Ref	Spin period (min)	-
Shell-burning/Accreting-only	shell-burning^Ref	Radius (R_⊙)	0.12-0.13^Ref, 0.10^Ref, 0.036±0.01^Ref, 0.066^Ref	Accretion disk	-
Eff. temperature (K)	50000-100000^Ref, 70000-90000^Ref, 75000^Ref, 110000±30000^Ref, 160000±10000^Ref	Luminosity (L_⊙)	100-1250^Ref, 200^Ref, 290^Ref, 2000-3300^Ref
Lower limit (K)	-
Upper limit (K)	-

Links

SIMBAD CDS Portal ARAS Database

Notes

Discovered by Merrill & Humason (1932), this star exhibited an "anomalous combination in a single spectrum of features which ordinarily occur near opposite ends of the sequence of stellar temperatures." Subsequent observations by Merrill & Burwell (1933) revealed the presence of TiO bands and a strong He II line. No outburst of this star has been recorded to date (Kenyon & Mikołajewska, 1995). Further investigations by Sion et al. (2002) reported possible outflows associated with the white dwarf component.

References

Allen, D. A., 1980, MNRAS, 192, 521, 1980MNRAS.192..521A
Dumm, T., Folini, D., Nussbaumer, H. et al., 2000, A&A, 354, 1014, 2000A&A...354.1014D
Dumm, T., Schmutz, W., Schild, H. et al., 1999, A&A, 349, 169, 1999A&A...349..169D
Garcia, M. R., 1986, AJ, 91, 1400, 1986AJ.....91.1400G
Gromadzki, M., Mikołajewska, J., Soszyński, I., 2013, AcA, 63, 4, 405, 2013AcA....63..405G
Kafatos, M., Michalitsianos, A. G., Hobbs, R. W., 1980, ApJ, 240, 114, 1980ApJ...240..114K
Kenyon, S. J., Fernandez-Castro, T., 1987, AJ, 93, 938, 1987AJ.....93..938K
Kenyon, S. J., Fernandez-Castro, T., 1987, ApJ, 316, 427, 1987ApJ...316..427K
Kenyon, S. J., Mikołajewska, J., 1995, AJ, 110, 391, 1995AJ....110..391K
Merc, J., Beck, P. G., Mathur, S. et al., 2023, arXiv, arXiv:2312.16126, 2023arXiv231216126M
Merrill, P. W., Burwell, C. G., 1933, ApJ, 78, 87, 1933ApJ....78...87M
Merrill, P. W., Humason, M. L., 1932, PASP, 44, 257, 56, 1932PASP...44...56M
Merrill, P. W., 1944, ApJ, 99, 15, 1944ApJ....99...15M
Michalitsianos, A. G., Kafatos, M., Hobbs, R. W. et al., 1980, Nature, 284, 5752, 148, 1980Natur.284..148M
Mikołajewska, J., Gałan, C., Hinkle, K. H. et al., 2014, MNRAS, 440, 4, 3016, 2014MNRAS.440.3016M
Mürset, U., Schmid, H. M., 1999, A&AS, 137, 473, 1999A&AS..137..473M
Schild, H., Mürset, U., Schmutz, W., 1996, A&A, 306, 477, 1996A&A...306..477S
Sion, E. M., Godon, P., Mikołajewska, J. et al., 2017, AJ, 153, 4, 160, 2017AJ....153..160S
Sion, E. M., Mikołajewska, J., Bambeck, D. et al., 2002, AJ, 123, 2, 983, 2002AJ....123..983S
Skopal, A., 2005, A&A, 440, 3, 995, 2005A&A...440..995S
Sokoloski, J. L., Bildsten, L., Ho, W. C. G., 2001, MNRAS, 326, 2, 553, 2001MNRAS.326..553S