* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Home -> Astronomy News -> Events -> Nova V1280 Scorpii
Post Info
TOPIC: Nova V1280 Scorpii
Blobrana


L

Posts: 131433
Date:
RE: Nova V1280 Scorpii
Permalink  
 

Title: Observational study of the extremely slow nova V1280 Scorpii
Authors: H. Naito, S. Mizoguchi, A. Arai, A. Tajitsu, S. Narusawa, M. Yamanaka, M. Fujii, T. Iijima, K. Kinugasa, M. Kurita, T. Nagayama, H. Yamaoka, K. Sadakane

We present multi-colour light curves and optical spectra of V1280 Scorpii obtained from 2007 to 2012. It is shown that V1280 Sco is the extremely slow nova and the mass of white dwarf appears to be ~ 0.6 solar masses or lower. Blue-shifted multiple absorption lines of Na{i} D, Ca{ii} HK, and He{i*} are detected on high-resolution spectra. We also discuss that an approach using metastable He absorption lines is useful to investigate structures of nova shells.

Read more (1623kb, PDF)



__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Title: Discovery of Metastable Helium Absorption Lines in V1280 Scorpii
Authors: H. Naito, A. Tajitsu, A. Arai, K. Sadakane

We report the discovery of blue-shifted metastable He I* absorption lines at 3188 A and 3889 A with multiple components on high-resolution spectra (R ~ 60,000) of V1280 Scorpii. Similar multiple absorption lines associated with Na I D doublet and Ca II H and K are observed. Na I D doublet absorption lines have been observed since 2009, while the metastable He I* absorption lines were absent in 2009 and were detected in 2011 (four years after the burst). We find different time variations in depths and velocities of blue-shifted absorption components among He I*, Na I, and Ca II. The complex time evolutions of these lines can be explained by assuming changes in density and recombination/ionisation rate when the ejecta expand and the photosphere contracts to become hotter. The multiple absorption lines originate in the ejected materials consisting of clumpy components, which obscure a significant part of the continuum emitting region. We estimate the total mass of the ejected material to be on the order of ~ 10^{-4} Mo, using metastable He I* 3188 and 3899 absorption lines.

Read more (2255kb, PDF)



__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Title: The expanding dusty bipolar nebula around the nova V1280 Sco
Authors: Olivier Chesneau (LAGRANGE), E. Lagadec (ESO), M. Otulakowska-Hypka, D. P. K. Banerjee (PRL), C.E. Woodward, E. Harvey (LAGRANGE), A. Spang (LAGRANGE), P. Kervella (LESIA), F. Millour (LAGRANGE), N. Nardetto (LAGRANGE), N. M. Ashok (PRL), M. J. Barlow (UCL), M. F. Bode (ARI, JMU), A. Evans, D.K. Lynch, T. J. O'Brien, R. J. Rudy, R. W. Russel

V1280 Sco is one of the slowest dust-forming nova ever historically observed. We performed multi-epoch high-spatial resolution observations of the circumstellar dusty environment of V1280 Sco to investigate the level of asymmetry of the ejecta We observed V1280 Sco in 2009, 2010 and 2011 using unprecedented high angular resolution techniques. We used the NACO/VLT adaptive optics system in the J, H and K bands, together with contemporaneous VISIR/VLT mid-IR imaging that resolved the dust envelope of V1280 Sco, and SINFONI/VLT observations secured in 2011. We report the discovery of a dusty hourglass-shaped bipolar nebula. The apparent size of the nebula increased from 0.30" x 0.17" in July 2009 to 0.64" x 0.42" in July 2011. The aspect ratio suggests that the source is seen at high inclination. The central source shines efficiently in the K band and represents more than 56±5% of the total flux in 2009, and 87±6% in 2011. A mean expansion rate of 0.39±0.03 mas per day is inferred from the VISIR observations in the direction of the major axis, which represents a projected upper limit. Assuming that the dust shell expands in that direction as fast as the low-excitation slow ejecta detected in spectroscopy, this yields a lower limit distance to V1280 Sco of 1kpc; however, the systematic errors remain large due to the complex shape and velocity field of the dusty ejecta. The dust seems to reside essentially in the polar caps and no infrared flux is detected in the equatorial regions in the latest dataset. This may imply that the mass-loss was dominantly polar.

Read more (945kb, PDF)



__________________
Blobrana


L

Posts: 131433
Date:
V1280 Scorpii
Permalink  
 

Title: Five-Year Optical and Near Infrared Observations of the Extremely Slow Nova V1280 Scorpii
Authors: H. Naito, S. Mizoguchi, A. Arai, A. Tajitsu, S. Narusawa, M. Yamanaka, M. Fujii, T. Iijima, K. Kinugasa, M. Kurita, T. Nagayama, H. Yamaoka, K. Sadakane

We present optical (B, V, R_{c}, I_{c} and y) and near infrared (J, H and K_{s}) photometric and spectroscopic observations of a classical nova V1280 Scorpii for five years from 2007 to 2011. Our photometric observations show a declining event in optical bands shortly after the maximum light which continues ~ 250 days. The event is most probably caused by a dust formation. The event is accompanied by a short (~ 30 days) re-brightening episode (~ 2.5 mag in V), which suggests a re-ignition of the surface nuclear burning. After 2008, the y band observations show a very long plateau at around y = 10.5 for more than 1000 days until April 2011 (~ 1500 days after the maximum light). The nova had taken a very long time (~ 50 months) before entering the nebular phase (clear detection of both [\ion{O}{iii}] 4959 and 5007) and is still continuing to generate the wind caused by H-burning. The finding suggests that V1280 Sco is going through the historically slowest evolution. The interval from the maximum light (2007 February 16) to the beginning of the nebular phase is longer than any previously known slow novae: V723 Cas (18 months), RR Pic (10 months), or HR Del (8 months). It suggests that the mass of a white dwarf in the V1280 Sco system might be 0.6 solar masses or smaller. The distance, based on our measurements of the expansion velocity combined with the directly measured size of the dust shell, is estimated to be 1.1 ± 0.5 kpc.

Read more (2275kb, PDF)



__________________
Blobrana


L

Posts: 131433
Date:
RE: Nova V1280 Scorpii
Permalink  
 

Observations by the Spitzer space telescope and the Infrared Telescope Facility (IRTF) on Mauna Kea show that significant amounts of dust is still present around  V1280 Scorpii.
The telescopes detected Unidentified InfraRed (UIR) emission features
which may indicate that a dense carbon-rich dust shell was released.

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Nova V1280 Scorpii (Nova Scorpii 2007a) was discovered by Yuji Nakamura, Kameyama, Mie, (Japan), on the 4th February 2007 in the constellation Scorpius. The nova reached magnitude 3.9 on the 17th February, 2007.

Magnitude     10.4 (min)
Magnitude     3.9 (max)

Position(2000): RA = 16h 57m 41.26s, Dec = -32° 20' 36.6"

IAUC 9046 (subscription)

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Watching a 'New Star' Make the Universe Dusty
VLTI observes for the first time how dust forms around an erupting star

Using ESO's Very Large Telescope Interferometer, and its remarkable acuity, astronomers were able for the first time to witness the appearance of a shell of dusty gas around a star that had just erupted, and follow its evolution for more than 100 days. This provides the astronomers with a new way to estimate the distance of this object and obtain invaluable information on the operating mode of stellar vampires, dense stars that suck material from a companion.

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Title: VLTI monitoring of the dust formation event of the Nova V1280 Sco
Authors: Olivier Chesneau (FIZEAU), Dipankar Banerjee (PRL), F. Millour, N. Nardetto, A. Spang (LG), S. Sacuto (FIZEAU), M. Wittkowski (ESO), N.M. Ashok (PRL), R.K. Das (PRL), Ch. Hummel (ESO), S. Kraus, Eric Lagadec (Universtiy Manchester), S. Morel (ESO), M. Petr-Gotzens (ESO), F.T. Rantakyro (ESO), M. Schöller (ESO)

We present the first high spatial resolution monitoring of the dust forming nova V1280 Sco performed with the Very Large Telescope Interferometer (VLTI). Spectra and visibilities were obtained from the onset of the dust formation 23 days after discovery till day 145, using the instruments AMBER and MIDI. These interferometric observations are complemented by near-infrared data from the 1.2m Mt. Abu Infrared Observatory, India. The observations are first interpreted with simple models but more complex models, involving a second shell, are necessary to explain the data obtained from t=110d after outburst. This behaviour is in accordance with the light curve of V1280 Sco which exhibits a secondary peak around t=106d, followed by a new steep decline, suggesting a new dust forming event. Spherical dust shell models generated with the DUSTY code are also used to investigate the parameters of the main dust shell. Using uniform disk and Gaussian models, these observations allow us to determine an apparent linear expansion rate for the dust shell of 0.35 ± 0.03 mas/day and the approximate time of ejection of the matter in which dust formed as t_ejec=10.5±7d, i.e. close to the maximum brightness. This information, combined with the expansion velocity of 500±100km/s, implies a distance estimate of 1.6±0.4kpc. The dust mass generated was typically 2-8 10^-9 solar mass per day. Considering that the dust forming event lasted at least 200-250d, the mass of the ejected material is likely to have exceeded 10^-4 solar mass.

Read more (146kb, PDF)

__________________
Blobrana


L

Posts: 131433
Date:
Nova Scorpii 2007 #1
Permalink  
 

Title: On Nova Scorpii 2007 N.1 (V1280 Sco)
Authors: Hanindyo Kuncarayakti, Desima Kristyowati, Chatief Kunjaya

We present the results of our photometric and spectroscopic observations of Nova Sco 2007 N.1 (V1280 Sco). The photometric data was represented by a single data point in the light curve since the observation was carried out only for one night. The spectra cover two different phases of the object's evolution during the outburst, i.e. pre-maximum and post-maximum. Measurements of the P-Cygni profile on Na I 'D' line (5889 \AA) was derived as the velocity of shell expansion, yielding 1567.43  ± 174.14 km s^{-1}. We conclude that V1280 Sco is a fast Fe II-type nova.

Read more  (326kb, PDF)

__________________
Blobrana


L

Posts: 131433
Date:
RE: Nova V1280 Scorpii
Permalink  
 

V1280 NOVA2007V1280

Expand (10kb, 792 x 554) ..................Expand (8kb, 792 x 554)

__________________
1 2  >  Last»  | Page of 2  sorted by
Quick Reply

Please log in to post quick replies.
Home -> Astronomy News -> Events -> Nova V1280 Scorpii


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard